The coffee's pH will be 10.
What does pH refer to?
An aqueous solution's acidity or basicity can be determined using the pH scale, which previously stood for "potential of hydrogen." In comparison to basic or alkaline solutions, acidic solutions are measured to have lower pH values.pH = pH3O+because hydrogen ions attach to water molecules for form hydronium ions.
To calculate the pH of a solution, use the equation
pH = − log [H3O+]
Since we are given the hydronium ion (H3O+) concentration of the solution, we can plug this value into the formula.
pH = −log[ 1.00 × 10^−10M]
pH = 10
Hence, The pH of this solution is 10
To learn more about ion concentration here :
brainly.com/question/4617925
#SPJ4
If metals and non-metals make bonds and non-metals and non-metals make bonds, can metals and metals do the same? how?
ASAP PLEASE
Answer:
Yes
Explanation:
Metals can bond with each other, both on a macroscopic level and on a molecular level. The former is found in any piece of metal, which is held together by metallic bonding. This can be more than one metal in the case of alloys, which are an intimate mixture of two or more different metals.
What is the heat capacity of 185g of liquid water?
The heat capacity of 185g of liquid water is 4.421 J/g°C
Heat capacity is defined as the amount of heat energy required to raise the temperature of a given quantity of matter by one degree Celsius
Here given data is
Mass = 185g
We have to calculate the heat capacity = ?
So the formula is
q = m×c×ΔT
c = ?
q = 4.184 J
m = 185g
ΔT = 100°C
c = m× ΔT/q
c = 185g ×100°C/ 4.184 J
c = 4.421 J/g°C
Heat capacity of 185g of liquid water is 4.421 J/g°C
Know more about heat capacity
https://brainly.com/question/13411214
#SPJ1
After transformation of e. Coli with pglo, why are the cells grown in lb broth for 20 minutes before plating on amp plates?.
The main purpose of spreading pGLO on the LB plate is to help bacteria to grow, otherwise the ampicillin would kill them. In case ,pGLO is not spread, then the cells would be killed by the ampicillin.
The Green Fluorescent Protein takes around 20 minutes to be transcribed and translated , on the other hand Arabinose promoter needs at least 20 minutes before RNA polymerase can bind to the promoter .
In general they have phenotypic lag of 20 minutes before the b-lactamase gene for Amp resistance can be expressed . we observe no growth of bacteria because it was not exposed to pGLO plasmid and lacked ampicillin resistance. If They were exposed to AMP and arabinose sugar, this cause bacteria to grow with ampicillin resistance.
therefore, The purpose of the cells grown on the LB plate is to help bacteria to grow, otherwise the ampicillin would kill them. In case ,pGLO is not spread, then the cells would be killed by the ampicillin.
To learn more about ampicillin resistance ,here
brainly.com/question/14546363
#SPJ4
Arrange the following solutions by increasing chloride ion molarity.
a. 1 M NaCl
b. 1 M FeCl3
c. 5 M NaCl
d. 1 M CaCl2
e. 2 M FeCl3
f. 2 M CaCl2
Arrangement of the solution By increasing order of molarity, is
option (a) < option (d) < option (b) < option (f) < option (c) < option (e)
Molarity is the amount of a substance in a certain volume of a solution. It is expressed as mole of the solute per liter of the solution. It is also known as molar concentration of the solution.
1M NaCl has, (1M Nacl/1L) . (1 molcl/1 mol) =1M.so the molarity of the Nacl is 1M.
1M FeCl3 have, ( 1M FeCl3 /1L ). (3 mol Cl /1 mol) = 3M. So. the molarity of the 1M Fecl3 is 3M.
5 m Nacl has, (5m Nacl/1l) . (1 mol cl/1 mole) =5M it has the molariry of 5M.
1M Cacl2 has, (1M Cacl2/1L) . (2mol cl/1 mole) = 2 mol. so it has the molarity of 2M.
2M Fecl3 has, (2M Fecl3 /1L) . (3mol cl/1 mole) = 6M. it has the molarity of 6M.
2M Cacl2 has, (2M Cacl2/1L) . (2mol cl /1 mole)=4M.The molar concentration of this is 4M.
hence, the solutions are arranged in increasing order.
To learn more about molar concentration please visit:
https://brainly.com/question/26255204
#SPJ4
If an atom has zero net charge, with 8 protons and 10 neutrons, how many electrons does
the atom have?
decide which element probably has a melting point most and least similar to the melting point of rubidium.
Florine is our least similar and cesium is our most similar in melting point.
Melting point is the temperature at which the solid and liquid forms of a pure substance will exist in equilibrium. As heat is applied to a solid, its temperature will increase till the melting point is reached.
If we apply more heat then it will convert the solid into a liquid with no temperature change. Now when all the solid has melted, additional heat will raise the temperature of the liquid. The melting temperature of crystalline solids is a very characteristic figure and it is used to identify pure compounds and elements.
From the melting point data we can say that florine will be least similar to rubidium and cesium will be most similar to rubidium.
To know more about melting point.
https://brainly.com/question/28902417
#SPJ4
the concentration of a solution expressed in moles of solute per 1 l of solution is called either the or the concentration, and is given the symbol m.
The concentration of a solution expressed in moles of solute per 1L of solution is called either the molarity or the molar concentration.
A solution is a homogenous mixture of one or more solutes dissolved in solvent. An example of solution is salt and water.
The most common way to express solution concentration is molarity(M) which is defined as the amount of solute in moles divided by the volume of solution in liters.
Molar concentration is a measure of the concentration of a chemical species.
To know more about molarity click here:
https://brainly.com/question/16727614
#SPJ4
Predict the products of the reactions, then balance the equation and identify the type of reaction.
(48 points: 8 points each= 2 points for reaction type, 4 points for products, 2 points for coefficients)
a. ___C3H8 + ___O2 → Reaction Type:
b. ___Ca + ___ Mg(NO3)2 → Reaction Type:
c. ___KOH + ___ HBr → Reaction Type:
d. ___Na + ___ O2 → Reaction Type:
e. ___ MgO → Reaction Type:
f. ___ K + ___Cl2 → Reaction Type:
The balanced equation of the reaction and the reaction types are given below as follows:
a. C₃H₈ + 5 O₂ → 3 CO₂ + 4 H₂O Reaction Type: Combustion
b. Ca + Mg(NO₃)₂ → Mg + Ca(NO₃)₂ Reaction Type: Single replacement
d. 4 Na + O₂ → 2 Na₂O Reaction Type: Oxidation or combination
e. 2 MgO → 2 Mg + O₂ Reaction Type: Decomposition
f. 2 K + Cl₂ → 2 KClReaction Type: Synthesis
What are chemical reactions?Chemical reactions are reactions in which chemical changes occur in one or more substances resulting in the formation of new substances.
Chemical changes that occur during chemical reactions are not easily reversible.
There are several types of chemical reactions and they include the following:
Double replacement or displacement reactionSingle replacement reactionsSynthesis reactionsCombustion reactionsLearn more about chemical reactions at: https://brainly.com/question/16416932
#SPJ1
which of the following chemical bonds is expected to be most polar? group of answer choices c-h p-f c-br br-br cl-br
The chemical bond that is most polar is, p-f. Correct answer: letter B.
The p-f bond is the most polar bond because it has the largest electronegativity difference between the two atoms. This means that the p-f bond will have a higher dipole moment than any other type of bond.
How is the p-f bond formed?The p-f bond is formed when the p orbitals of two atoms overlap. The p orbitals are larger than the s orbitals, so the p-f bond is larger than the s-f bond. The p-f bond is also stronger than the s-f bond because the p orbitals are closer to the nucleus than the s orbitals.
Learn more about chemical bonds polares:
https://brainly.com/question/25150590
#SPJ4
Why are the products of an exothermic reaction likely to be warmer than the reactants?.
The products of an exothermic reaction likely to be warmer than the reactants because in this reaction energy produced is released as heat.
An exothermic reaction is a reaction in which energy is released in the form of light or heat. So, in an exothermic reaction, energy is transferred into the surroundings rather than taking energy from the surroundings as in the case of endothermic reaction.
We can also say that the exothermic reactions are the ones that actually release heat after the chemical reactions. For example matching a light using a matchstick is one example of this type of reaction where the release of energy is in the form of both heat and light.
So, in these kinds of reaction the products of these reactions are more likely to me warmer than the reactants.
To know more about exothermic reaction
https://brainly.com/question/17022982
#SPJ4
Which of the following is FALSE * 1 point
for mixtures and compounds?
Mixtures have variable composition,
compounds have fixed compositions
The properties of a mixture is
different to the properties of its
constituent elements
Mixtures are easy to separate,
compounds are difficult to separate
There is no change in energy when a
compound is made
The compounds are not easy to separate and mixtures are easy to separate.
Compounds are substances formed by the chemical combination of two or more elements. Mixtures are substances formed by physically mixing two or more substances together.Mixtures are substances made up of two or more different types of materials. Physical means can be used to separate them. A mixture of salt and water, a mixture of sugar and water, various gases, air, and so on are examples. A mixture doesn't require a chemical process to form. It is formed by simple physical processes where two or more mutually non-reactive substances are mixed, in not necessarily fixed proportions. So it is different than separating a mixture of compounds.To learn more about mixture visit:
brainly.com/question/24898889
#SPJ1
help me please write the correct formula
The formulas of each of the compounds are;
1) AlN
2) [tex]NH_{4} ^+[/tex]
3) [tex]C_{3} H_{8}[/tex]
What is a chemical formula?The term chemical formula has to do with the representation of a compound. We know that the way that a compound is represented would help us to be able to identify the compound.
We have various compounds that have been shown in the image and we are asked to find the correct formula of the compound. We now look at the number of atoms that we have in each of the diagrams and by means of the number of atoms, we would look to see how we can be able to find the chemical formula of the compound.
By the octet rule, aluminum can combine with nitrogen to form aluminum nitride. The combination of nitrogen with four hydrogen atoms would only lead to the formation of a charged ammonium specie. A structure that contains three carbon atoms and eight hydrogen atoms can only be propane as shown.
Thus, when we see the arrangement of the atoms we now have to look at the possible compound that could be found from the arrangement shown and then write down the formula of the compound as shown.
Learn more about chemical formula:https://brainly.com/question/29031056
#SPJ1
In a reaction a + b ----> c, reactant a has 5g and product c has 9g. How many grams does reactant b should have?.
Answer:
b = 4g
Explanation:
1. Subtract 5 from both sides of the equation.
b = 9g - 5g
2. Subtract 5 from 9.
b = 4g
which of the following molecules is thought to have been absent from the primitive reducing atmosphere of early earth?
The following molecules is thought to have been absent from the primitive reducing atmosphere of early earth is oxygen , O₂.
The primitive earth of the atmosphere is consist of the hydrogen that will combined to the oxygen atoms, and for the water molecules H₂O and leaving the no hydrogen left free. that mean the the primitive reducing atmosphere of the early earth is oxygen , O₂. the original earth atmosphere is rich in methane , water vapor and ammonia.
Thus, The following molecules is thought to have been absent from the primitive reducing atmosphere of early earth is oxygen , O₂.
To learn more about earths atmosphere here
https://brainly.com/question/1267862
#SPJ4
Rank the following species by radius, from largest to smallest:
cl−, k , ca2, ar, s2−.
The rank of the species by radius from largest to smallest: [tex]S^{2-} > Cl^{-} > Ar > K^{+} > Ca^{2+}[/tex]
All Ions are isoelectronic, which means the elements can have the same number of electrons but, their radii would be different because they have different nuclear charges. Atomic radii can be predicted easily. The atomic radii in the periodic table increase from top to bottom coming from left to right.
The cation with a greater positive charge will have a small radius due to the great attraction of electrons. The Anion with a greater negative charge will have a large radius due to the less attraction of electrons. Therefore, the ion will expand in size due to the net repulsion of the electrons.
To know more about Ranking the species by radius from largest to smallest at:
https://brainly.com/question/19032815
draw the lewis structure for pcl6, then answer the following questions: 1. how many valence electrons does this compound have? 2. how many bonded electrons does this compound have? 3. how many lone pairs of electrons does this compound have? 4. how many single bonds does this compound have? 5. how many double bonds does this compound have? 6. what is the electron group arrangement {aka electron pair geometry} (enter one of the following: linear, trigonal planar, tetrahedral, trigonal bipyramidal, octahedral)? 7. what is the molecular geometry {aka shape} (enter one of the following: linear, trigonal planar, tetrahedral, trigonal pyramidal, bent, trigonal bipyramidal, seesaw, t-shaped, octahedral, square pyramidal, square planar)?
The Pcl6 has 48 bonded electrons and 18 lone pairs.
The Lewis structure of Pcl6 is as follows: -
Phosphorous is bonded with 6 chlorine atoms with 18 lone pairs.
Lewis structures, also known as Lewis dot formulas, Lewis dot structures, electron dot structures, or Lewis electron dot structures (LEDS), are diagrams that show the bonding between atoms of a molecule, as well as the lone pairs of electrons that may exist in the molecule. [1][2][3] A Lewis structure can be drawn for any covalently bonded molecule, as well as coordination compounds.
In Lewis structure, atoms are bonded with single bonds. If total number of electrons are 't' and number of bonds are 'n', then t-2n number of electrons are to be placed. Once the central atom is placed, they need to complete the octet rule.
Learn more about Lewis-dot structure from,
https://brainly.com/question/18083461
#SPJ4
WILL GIVE BRAINLIEST!! (Just learned how)
The measured bond energies (kJ/mol) of several compounds was determined to be A = 350, B = 500, C = 180, and D = 1,450. Which compound will most likely conduct electricity when dissolved in water?
A. compound A
B. compound C
C. compound B
D. compound D
Answer:
D) Compound D
Explanation:
The bond energy is the highest amount the listed bond energies and this is one of the characteristics of ionic compound because usually its involves the formation of anions and cations with the former being negative and the latter being positive.
The bond is usually strong because it is involves attraction between actions and anions. It requires transfer of electron between metals and nonmetals. The metals are usually the cations (lose electron) and nonmetals are usually the anions ( they gain electron) so when they are dissolve in water they dissociate into negative and positive ions and carries electrical charges while in solid form they are insulators example is NaCl
Answer:
Compound D
Explanation:
A WHAT has to do with the direction of a force. Please Help
A. vector
B. scalar
C. speed
D. velocity
E. newton
Consider the reaction
N2 + 3 H2 → 2 NH3 .
How much NH3 can be produced from the reaction of 74.2 g of N2 and 14.0 moles of H2?
The mass of ammonia that can be produced from the reaction of 74.2 g of N₂ and 14.0 moles of H₂ is 90.1 g.
What is the mole ratio of the reaction for the production of ammonia?The mole ratio of the reaction for the production of ammonia is obtained from the balanced equation of the reaction as follows:
Equation of the reaction: N₂ (g) + 3 H₂ (g) → 2 NH₃ (g)
The mole ratio of the reactants nitrogen and hydrogen is 1 : 3
Moles of nitrogen in 74.2 g of nitrogen = 74.2/28
Moles of nitrogen in 74.2 g of nitrogen = 2.65 moles
Moles of hydrogen present = 14.0 moles
The limiting reactant is nitrogen
Mole ratio of nitrogen to ammonia is 1 : 2
Mass of ammonia produced = 2.65 * 2 * 17 g
Mass of ammonia produced = 90.1 g
Learn more about mole ratio at: https://brainly.com/question/19099163
#SPJ1
the greater the lattice energy, the greater the charges on the participatory ions and the smaller their radii. the greater the lattice energy, the greater the charges on the participatory ions and the smaller their radii. true false
True, the greater the lattice energy, the greater the charges on the participatory ions and the smaller their radii.
Lattice energy is the term used to describe the energy created when two gaseous ions with opposing charges are drawn to one another and eventually form an ionic bond.
Due to the tight bonding of ionic bonds, lattice energy is always positive and typically has a brittle crystalline structure.
They are not easily deformed due to the presence of a strong electrical link, and because of the arrangement of ions, they melt at a very high temperature.
As lattice energy rises, ionic bond strength rises as well. Additionally, the size or radius of the ions as well as the charge of the ions affect the lattice energy.
The radius of the Ion: The lattice energy decreases as the ion radius rises. The lattice energy reduces as the halide size grows down the group. This is due to the fact that when ions become larger, their nuclei become farther apart. As a result, there is less attraction between them, which ultimately results in less lattice energy being produced.Charge of ions: Due to the ions' stronger attraction to one another, lattice energy rises as ion charge increases. In comparison to +1 or -1 ions, +2 or -2 ions will therefore release more lattice energy.Learn more about the lattice energy here:
https://brainly.com/question/13169815
#SPJ4
Calculate the amount of heat neceary to raie the temperature of 47. 8 g ethylene glycol by 57. O K. The pecific heat capacity of ethylene glycol i 2. 433j/gc
Th amount of heat necessary to raise the temperature of 47.8g ethylene glycol by 57 K is 6593.532J.
What is ethylene glycol?
Ethylene glycol is a water-absorbing synthetic liquid. It has no odour and a sweet taste. Ethylene glycol is used in the manufacture of antifreeze and deicing solutions for automobiles, aeroplanes, and boats. It's also found in hydraulic brake fluids and inks used in stamp pads, ballpoint pens, and printing presses.
Th amount of heat necessary to raise the temperature of 47.8g ethylene glycol by 57 K is 6593.532J.
To calculate the amount of heat transferred (q) is the product of specific heat capacity(C), mass of substance(m) and the change in temperature(ΔT).
q=m×c×ΔT
Here m=47.8g , C=2.42J, ΔT= 57K
q= 6593.532J
To learn more on ethylene glycol from the link:
https://brainly.com/question/11994953
#SPJ4
A student makes a model of a cell. He uses a plastic bag to represent the cell membrane. He fills it with a clear gel to represent the cytoplasm. He puts in other materials to represent parts of the cell within the cell membrane. His teacher tells him that the plastic bag is not a good representation of the cell membrane. She suggests that the student find a material that better shows how a cell membrane works. The student makes another model using a woven cloth bag to represent the cell membrane. The teacher tells him that he made a good choice. Why is the woven cloth a good choice for improving the student’s cell model?
The woven cloth is a good choice for modeling a cell membrane because cell membranes are semipermeable, which means some particles can cross the cell membrane while others cannot. Unlike the plastic bag, the woven cloth is semipermeable: for the woven cloth, small particles/liquids can pass through it while larger objects cannot. However, nothing is able to pass through the plastic bag, so the plastic bag is not semipermeable (it's impermeable).
The specific heat of liquid ethanol, c2h5oh(l), is 2. 46 j/g·°c and the heat of vaporization is 39. 3 kj/mol. The boiling point of ethanol is 78. 3 °c. What amount of enthalpy is required to heat 50. 0 g of liquid ethanol from 23. 0 °c to ethanol vapor at 78. 3 °c?.
The enthalpy required to heat 50 g of liquid ethanol from 23 °C to ethanol vapor at 78.3 °C is 50. kJ.
We want to heat 50 g of liquid ethanol from 23 °C to ethanol vapor at 78.3 °C. We can divide this process in 2 parts:
Heating of liquid ethanol from 23 °C to 78.3 °C (boiling point).
Vaporization of ethanol at 78.3 °C.
1. Heating of liquid ethanol from 23 °C to 78.3 °C
The amount of heat required for this part (Q₁),
Q₁ = c × m × ΔT
Q₁ = (2.46 J/g °C) × 50 g × (78.3 °C - 23 °C) × (1 kJ/1000 J) = 6.8 kJ
where,
c = specific heat of liquid ethanol.
m = mass of ethanol.
ΔT = change in the temperature.
2. Vaporization of ethanol at 78.3 °C.
The amount of heat required for this part (Q₂),
Q₂ = (m/M) × ΔH°vap
Q₂ = [50 g/(46.07g/mol] × (39.3 kJ/mol) = 43 kJ
where,
m = mass of ethanol.
M = molar mass of ethanol.
ΔH°vap = enthalpy of vaporization of ethanol.
The total amount of heat required (Q) = the sum of the heat required in each step.
Q = Q₁ + Q₂ = 6.8 kJ + 43 kJ = 50. kJ
Let the process is carried out at constant pressure and the enthalpy required for the process = 50. kJ.
The enthalpy required to heat 50 g of liquid ethanol from 23 °C to ethanol vapor at 78.3 °C is 50. kJ.
To know more about ethanol
https://brainly.com/question/25002448
#SPJ4
Compare and contrast metallic and ionic bonds, including the element groups they are made of, the behavior of electrons, and their typical properties.
The Compare and contrast of metallic and ionic bonds is given below.
Ionic and metallic bonds take occur between positive and negative ions, whereas ionic bonds take place between positive ions and electrons. This is the main distinction between the two types of bonds.
Ions, which are made up of a positive and a negative ion, are created when two atoms exchange electrons. Atoms sharing electrons to form a molecule result in covalent bonds. Metal atoms shed their outermost electron to produce positively charged ions, which then form metallic bonds.
Metal ions are attracted to delocalized or free e, forming metallic connections as a result. whereas ionic bonds are created by electron transfer from one atom to another.
What is the similarity between metallic and ionic bonds?Similar to ionic bonds, where the removal of electrons results in the formation of ions, metallic bonds include the removal of electrons to create a sea of electrons.
Later, these electrons are used or shared by each and every atom, and in covalent bonds, two atoms share one electron. Consequently, metallic bonds resemble both ionic and covalent bonds.
Ionic and metallic solids differ significantly in that metallic solids contain metal atoms and free electrons while ionic solids mostly comprise cations and anions.
Additionally, metallic solids feature metallic bonds rather than the electrostatic attraction forces between cations and anions that exist in ionic solids.
Learn more about ionic bonds from
https://brainly.com/question/2687188
#SPJ1
According to the Law of Conservation of Mass, which box on the right correctly demonstrates the product of this reaction?
A
B
C
D
Answer:
The answer is D
Explanation:
The number of particles is equivalent in both images.
Hope this helps!!
13.67 a mizture of methane and 200% of the theoretical air, initially at 77 f, 1 atm, reacts completely in an insulated vessel. determine the temperature in f of the combustion products if the reaction occurs a) at constant volume, b) at constant pressure in a piston-cylinder assembly
The temperature at constant volume is 0.311, The temperature at constant pressure is 5.133.
What is mixture?
A mixture in chemistry is a compound composed of two or more chemical components that are not chemically linked. A mixture is a physical combination of two or more substances that retain their identities and are blended as solutions, suspensions, or colloids.
GIVEN :
Air = 200%
p = 77f, 1 atm
PV=nRT
1*200/100 = 12(77)T
= 0.3311
1*80/100 = 12(77)T
= 5.133
To learn more about Mixture, from the given link:
https://brainly.com/question/24647756
#SPJ4
10. challenge question 2: a few small drops of water are left in a buret that is then used to titrate a base into an acid solution to determine the concentration of the acid. will this small amount of water have any effect on the determined value for the concentration of the acid? if so, how is it affected?
Yes, this small amount of water will have effect on the determined value for the concentration of the acid.
How small amount of water affect concentration of acid?Even small amount of water causes an error because the drops of water add to the volume of base, diluting it slightly. This means it will take more base solution to neutralize the acid. This makes it seem as if the acidic solution was of stronger concentration than it actually was.
Method of quantitative analysis for determining the concentration of an acid or base by neutralizing it exactly with a standard solution of base or acid having known concentration is known as an acid–base titration
To know more about titrations of base in acid, refer
https://brainly.com/question/23687757
#SPJ4
Which moon phase is pictured below?
Some people believe that certain drugs such as marijuana should be legalized. Do you agree or disagree? What impact might legalization have on forensic science as a field?
If the hard drugs are legalized, there would be an astronomical increase in crime rate that forensic scientist may be unable to handle.
Why should hard drugs not be legalized?There are certain drugs that are known to have the ability to affect the mood and the perceptions of a person. If an individual takes any of the drugs in this category, the individual may become unable to make effective use of his or her mind and this would impact on the ability of the person to make sound decisions.
The intake of so many drugs in this category have been responsible for a lot of crimes as can be confirmed by the foresnsic specialists. This is why in many places, the use of any of the drugs in this category is being strongly controlled.
As such, the legalization of the use of these drugs would increase the rate of crime and put a lot of pressure on the field of forensic science.
Learn more about forensic science:https://brainly.com/question/21601148
#SPJ1
Question 1 (1 point)
A new element has been discovered at Archer High School. The element symbol is Zz
and it has 2 naturally occurring isotopes.
The first isotope has a mass of 85.96 amu and a percent abundance of 87.20%.
The second isotope has a mass of 86.78 amu.
What is the average atomic mass of element Zz? Round to the hundredth's place
(0.01 or 2 decimal places).
Your Answer:
Answer
units
Answer:
86.06 amu is the average atomic mass of element Zz.
Explanation:
We may find the average atomic mass of Zz with a simple thought experiment. Let's imagine that we were given 100.0 grams of Zz. We know that 87.20% of that 100.0 grams is an isotope having 85.96 AMU (atomic mass units). That means the other 12.80% must be the isotope with 86.78 AMU.
Since we picked 100.0 grams, it is easy to see that we would have:
87.2 grams of 85.96 AMU, and
12.8 grams of 86.78 AMU
-----------
100.0 grams total
The contribution of each isotope can be calculated by taking it's percent abundance times it's AMU andf then adding the total results:
AMU % Contribution to total AMU
85.96 87.2 74.96
86.78 12.8 11.11
-------- --------- -----------
100.0 86.06 amu
The sum of the two weighted averaged amu numbers is the average atomic mass of element Zz. [Element Zz has a good futire as a sleep aid.]