14 In which group are all the elements found
naturally only in compounds?
(1). 18
(3) 11
(2) 2
(4) 14
Please help me.
a 750 sample of technetium-99 decays in 4 half lifes, how much of the sample will remain?
Answer:
93.75
Explanation:
In first half life 750×1/2 will remain
In second one half from that remained at the end of first half life will remain
That is 1/2 × 750×1/2
likewise at the end of 3rd half life 1/2 × 1/2 ×750×1/2 remains
at the end of 4th half life 1/2 × 1/2 × 1/2 ×750×1/2 remains
1/2 × 1/2 × 1/2 ×750×1/2 = 93.75 remains.
You can also use the equation
Remainder = X × 1/2^n .
This saves time
n= no. of half lives
X= initial amount
so in this case 1/2^4 × 750 = 93.75
What is called exothermic
An exothermic process is one that gives off heat.
Explanation:
This heat is transferred to the surroundings. An endothermic process is one in which heat has to be supplied to the system from the surroundings.
discuss the solubility differences between the halogens and the halides in both hexane and water. be sure to define what a halogen and halide are to foundation your discussion.
Halides are ionic substances while halogens nonpolar substances. Hence, halides dissolves in water while halogens dissolve in hexane.
A halogen is an element in group seventeen. The name halogen means salt former. This name came about because many of the halogens form salts. Halides are salts formed by the halogens.
Halogens are diatomic covalent molecules. As such, they are nonpolar molecules and can only effectively interact with nonpolar solvents. Benzene is a nonpolar solvent hence it acts as an effective solvent for the halogens.
The halides are polar compounds hence they do not dissolve in nonpolar solvents such as hexane. Rather, halides dissolve in polar solvents such as water due to dipole - dipole interaction between the ions in the halide and the dipoles in water.
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if the column of water in the water barometer rose to a height of 36 feet, what would the atmospheric pressure be in mm hg?
The Atmospheric pressure is usually constant and is; 760mm Hg.
According bro the question;
The column of water in the water barometer rose to a height of 36 feet.The absolute pressure is given as;
P(abs) = P(atm) + P(gauge)The gauge pressure is dependent on the height of the water column.
Ultimately, the atmospheric pressure is constant and is given as; 760mm Hg.
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Distinguish between the first, second, and third ionization energies of an atom. b. How do the values of successive ionization energies compare
Answer:
The third ionization energy is the energy it takes to remove an electron from a 2+ ion. (That means that the atom has already lost two electrons, you are now removing the third.) And 2nd ionization energy is higher than 1st ionization energy, 3rd is higher than 2nd, and so forth.
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Convection currents are one force driving plate tectonics. What other force plays a major role?
Heat transfer
Gravity
Radioactive decay
Fossil formation
Answer:
Gravity
Explanation:
Gravity was founded by famous physician Sir Izak Newton.The gravity is a phenomenon by which every object in the universe attracts eachotherNewton discovered gravity by the falling apple from tree.The following factors contribute to plate tectonics: The Mantle's Convection. Mountain push gravitational force at the spreading ridges, Block pull gravitational force in subduction zones. Hence, option B is correct.
What is gravitational force ?The gravitational force, which is what pushes mass-containing objects toward one another. We frequently consider the pull of gravity from the Earth. Your body is kept on the ground by this force. However, all mass-bearing objects are pulled toward one another by gravity.
Population growth and changes in people's wants and activities are the main causes behind this. Changes in the overall levels of output and consumption are caused by these main movers.
The driving forces put strain on the environment through these modifications to production and consumption. In the direction of motion, gravity produces an active driving force.
Thus, option B is correct.
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How many atoms of lithium are there in 18.2mg of lithium? Dimensional analysis only!
Answer:7.25
Explanation:
This is because 18.2 - 7.2 = 11 +7.2 = 18.2
When we lower the temperature of the solvent, the rate of dissolving of the solute will....?
Answer:
Decrease
Explanation:
An increase in temperature would increase the dissolution rate and a decrease in temperature would decrease the dissolution rate
Answer:
The rate of dissolving of the solute will increase I think
What are the word equations for the following? Please help
Calcium oxide + water
Magnesium + hydrochloric acid
Sodium hydrogen carbonate + citric acid
Iron + salt water
Calcium oxide + water = calcium hydroxide.
Magnesium + hydrochloric acid = magnesium chloride + hydrogen.
Sodium hydrogen carbonate + citric acid = Na3C6H5O7(aq)+3H2O(l)+3CO2(g)
Iron + salt water = 4Fe(OH)3 (rust)
Answer:
1. CaO + H2O _____ Ca(OH)2
Calcium oxide + Water _____ Calcium hydroxide
2. 2 HCI + MG _____ MgCl2 + H2
Magnesium + hydrochloric acid _____ Magnesium Chloride + hydrogen gas
How are traits inherited?
Please explain thoroughly
inherited traits are passed from parent to offspring according to the rules of Mendelian genetics. Most traits are not strictly determined by genes, but rather are influenced by both genes and environment
Determine the wavelength of the light absorbed when an electron in a hydrogen atom makes a transition from an orbital in which n=2n=2 to an orbital in which n=7n=7.
Answer:
The expression for the wavelength of radiation is,
λ
1
=R(
n
1
2
1
−
n
2
2
1
)
Substitute values in the above expression,
λ
1
=109677×(
2
2
1
−
4
2
1
)=109677×(
4
1
−
16
1
)=109677×(
64
12
)
λ=4.86×10
−5
cm=486×10
−9
m=486nm.
The line belongs to bluish green colour.
4.16 Unit Test: Chemical Bonding - Part 2 1. You are studying alkaline earth metals bonding with Halogens. Using your knowledge of the ionic bonding, what specific and testable scientific question could be asked about the salt formation
A testable scientific question could be asked about the salt formation is; "Is the salt soluble in water?
A scientific question is a question that can be answered by experiments. In other words, a scientific question must be empirical. Its answer can only be obtained by carrying out experiments.
In the case of bonding in alkaline earth metals, the kind of bond formed is ionic. Ionic compounds are soluble in water. Hence, a testable scientific question could be asked about the salt formation is; "Is the salt soluble in water?
This can be answered by dissolving several salts of alkali earth metals in water.
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A student was performing paper chromatography and let the separation continue overnight. The
A student was performing paper chromatography and let the separation continue overnight. The student wished to determine if the mixture contained a substance with an RF factor of 0.343 where:
Rf = (distance travelled by the component)/(distance travelled by the solvent)
a) What data would be affected by this error?
b) Explain the effect on the calculated Rr.
Based in the information given, the data that'll be affected by the error is the value of the solvent data.
It should be noted that the data that'll be affected based on the scenario given is the value of the solvent. When the preparation is kept overnight, there'll be an overflow of the solvent.
In such a case, it'll be difficult to get the correct distance that the solvent travelled. The effect on the calculated Rr is that the calculated Rr will be incorrect due to the error in solvent value.
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which of the following best describes the relation ship between oxygen and chlorine
A. Oxygen and chlorine have the same symbols
B. Oxygen atoms have fewer protons than chlorine atoms
C. Oxygen and chlorine have the same properties
D. Oxygen atoms have twice as many protons as chlorine atoms
Answer:
B
Explanation:
The oxygen atoms have fewer protons than chlorine atoms:) hope this helps:))
According to the electronic configuration, oxygen atoms have fewer protons and electrons than chlorine atoms.
What is electronic configuration?Electronic configuration is defined as the distribution of electrons which are present in an atom or molecule in atomic or molecular orbitals.It describes how each electron moves independently in an orbital.
Knowledge of electronic configuration is necessary for understanding the structure of periodic table.It helps in understanding the chemical properties of elements.
Elements undergo chemical reactions in order to achieve stability. Main group elements obey the octet rule in their electronic configuration while the transition elements follow the 18 electron rule. Noble elements have valence shell complete in ground state and hence are said to be stable.
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An iron object alloyed with cobalt rusts more quickly than a pure iron object. However, an iron object alloyed with manganese rusts less quickly than a pure iron object under the same conditions. This is true because: __________
a. cobalt is a stronger reducing agent than iron
b. iron is a stronger reducing agent than manganese
c. cobalt exhibits more metallic character than either iron or manganese in the iron-manganese alloy
Rusting is an electrochemical reaction. Iron rusts faster when alloyed with cobalt than when alloyed with manganese because, in the iron-manganese alloy, manganese is rendered the anode and iron is rendered the cathode
An alloy is a combination of two metals. There are various reasons for producing alloys such as greater tensile strength, corrosion resistance and improved aesthetic appearance.
When iron is alloyed with cobalt, the iron rusts faster than pure iron because iron is rendered the anode and cobalt is rendered the cathode. When the iron is alloyed with manganese, it rusts more slowly than pure iron because in the iron-manganese alloy, manganese is rendered the anode and iron is rendered the cathode.
Missing parts;
An iron object alloyed with cobalt rusts more quickly than a pure iron object. However, an iron object alloyed with manganese rusts less quickly than a pure iron object under the same conditions. This is true because
(1) cobalt is a stronger reducing agent than iron
(2) iron is a stronger reducing agent than manganese
(3) cobalt exhibits more metallic character than either iron or manganese
(4) in the iron-manganese alloy, manganese is rendered the anode and iron is rendered the cathode
(5) in the iron-cobalt alloy, cobalt is rendered the anode and iron is rendered the cathode
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Choose the statement that is TRUE. Question 26 options: Outer electrons efficiently shield one another from nuclear charge. All of the answers are true Valence electrons are most difficult of all electrons to remove. Core electrons effectively shield outer electrons from nuclear charge. Core electrons are the easiest of all electrons to remove.
The statement which is true is Core electrons effectively shield outer
electrons from nuclear charge.
Core electrons are those which are in close proximity with the nucleus. The
core electrons repel the outer electrons farther away from the nucleus to
shield it from nuclear charge.
The valence electrons are usually found in the outermost part of the shell
and they are the easiest to remove due to the fact that they have to achieve
a stable octet configuration which makes them easily removed during
chemical reactions.
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Answer: core electrons effectively shield outer electrons from nuclear charge
Explanation:
Notice that the bond strength for lithium bonded with any of the anions is larger than the bond strength of potassium bonded with any of
the same anions. Propose a scientifically sound explanation for this.
Select one:
O a. Lithium comes before sodium or potassium alphabetically, so its bond will be stronger.
O b. Sodium and potassium are essential for human metabolism, so they should not bond as strongly with anions.
Oc. Lithium is the smallest cation, so bond length is shorter creating a tighter bond.
Od Lithium is the only cation with a +1 charge.
Check
The bond strength for lithium bonded with any of the anions is larger than the bond strength of potassium bonded with any of the same anions because lithium is the smallest cation, so bond length is shorter creating a tighter bond.
The strength of an ionic bond ultimately depends on the size of the ions. The smaller the ions the stronger the bond and the higher the lattice energy. Such compounds having a high lattice energy tend to deviate from the normal behavior of ionic crystals due to significant covalent contribution.
Lithium is the smallest cation in group 1. Hence, the bond strength for lithium bonded with any of the anions is larger than the bond strength of potassium bonded with any of the same anions because lithium is the smallest cation, so bond length is shorter creating a tighter bond.
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Which element has 12 protons 12 neutrons and 12 electrons
Answer:
Magnesium
Explanation:
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray solid which bears a close physical resemblance to the other five elements in the second column of the periodic table: all group 2 elements have the same electron configuration in the outer electron shell and a similar crystal structure.
What are the major reservoirs for sulfur
Answer:
the ocean, the ocean floor basalts, evaporite deposits and reduced marine sediments.
Explanation:
describe how fluids exert forces on objects
Explanation:
Fluids exert forces on objects because of many molecules of the fluid that continuously collide with the surfaces of the object immersed in the fluid. Squeezing a plastic mustard bottle forces mustard out the top because of the amount of force or pressure applied to it that results in mustard coming out.
When an object is immersed in a fluid, the fluid exerts an upward force known as buoyancy. The buoyant force is caused by the fluid's pressure on the object.
How does fluids exert forces on objects?The upward force exerted by fluids on all matter is known as buoyant force. Force According to Archimedes' principle, the buoyant force on an object in a fluid is an upward force equal to the weight of the fluid that the object replaces or displaces.
A submerged object's buoyant force is equal to the weight of the fluid displaced. By measuring the mass of an irregularly shaped object, this principle can be used to determine its volume and thus density.
Squeezing a plastic mustard bottle forces mustard out the top due to the amount of force or pressure applied to it, which causes mustard to come out.
Thus, Fluids exert forces on objects because their molecules constantly collide with the surfaces of the objects immersed in the fluid.
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29.0 argon combine completely with 4.30 g of Sulfur.
Calculate the percent compositions of the compounds that are formed from the reaction
Answer:
33.3
Explanation:
if we were to add 29.0 of argon and 4.30 of sulfur and that would come out 33.3.
Determina la molaridad de una solución de H2S, si se colocaron 37 ml del ácido en 890 ml de solución. La densidad del H2S es de 1.36 g/ml
Por definición de molaridad y densidad, la molaridad de la solución es 1.66 [tex]\frac{moles}{litros}[/tex].
La concentración molar o molaridad es una medida de la concentración de un soluto en una disolución que indica el número de moles de soluto que están disueltos en un determinado volumen.
La molaridad de una solución se calcula dividiendo los moles del soluto por el volumen de la solución:
[tex]Molaridad=\frac{numero de moles de soluto}{volumen}[/tex]
La Molaridad se expresa en las unidades [tex]\frac{moles}{litros}[/tex].
Por otro lado, la densidad es una magnitud que permite medir la cantidad de masa que hay en determinado volumen de una sustancia.
Entonces, la expresión para el cálculo de la densidad es el cociente entre la masa de un cuerpo y el volumen que ocupa:
[tex]densidad=\frac{masa}{volumen}[/tex]
En este caso, siendo H₂S el soluto, se colocaron 37 ml del ácido, siendo su densidad 1.36 [tex]\frac{g}{mL}[/tex]. Reemplazando en la definición de densidad se obtiene:
[tex]1.36\frac{g}{mL}=\frac{masa}{37 mL}[/tex]
masa= 1.36 [tex]\frac{g}{mL}[/tex]× 37 mL
masa= 50.32 g
Siendo 34 g/mol la masa molar de H₂S, es decir la cantidad de masa que una sustancia contiene en un mol, la cantidad de moles de H₂S puede ser calculada como:
[tex]numero de moles de H_{2}S= 50.32 grams\frac{1 mole}{34 grams}[/tex]
número de moles de H₂S= 1.48 moles
Siendo 890 mL=0.890 L el volumen de la solución, entonces la molaridad puede ser calculada como:
[tex]Molaridad=\frac{1.48 moles}{0.890 L}[/tex]
Molaridad= 1.66 [tex]\frac{moles}{litros}[/tex]
Finalmente, la molaridad de la solución es 1.66 [tex]\frac{moles}{litros}[/tex].
Aprende más:
https://brainly.com/question/17647411?referrer=searchResultshttps://brainly.com/question/21276846?referrer=searchResultsWrite the empirical formula of at least four binary ionic compounds that could be formed from the following ions: Ca2+, Al3+, Cl−, O2−
Answer:
CaCl2
CaO
Al2O3
AlCl3
You can do this by swapping the values of charges on the ions as below
eg- Ca2+ - 2
Cl- - 1
Now combine 1 Ca atom and 2 Cl atoms and it will give you CaCl2
Al 3+ - 3
O2- - 2
Combine 2 atoms of Al and 3 atoms of O
Al2O3
In the case of CaO, we have to make sure that the atoms are in their simplest ratio. So although we get Ca2O2, CaO is the correct form
Please help! Giving 20 points!
Question: How can NASA scientists use Newton's third law of motion to plan for a space vehicle landing on a meteor? Make a claim. Support your claim with evidence from the article. Then, explain why the evidence supports your claim.
Article: https://newsela.com/read/lib-newton-third-law/id/54749/
Answer:
Explanation:
NASA uses rockets to launch astronauts and supplies to the International Space Station. Launching a rocket relies on Newton's Third Law of Motion. A rocket engine produces thrust through action and reaction. The engine produces hot exhaust gases which flow out of the back of the engine
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what type of intermolecular force causes the dissolution of nacl in water?
Answer:
ion-dipole forces
Explanation:
positive sodium ion will be attracted to the slightly negative oxygen atoms in the water molecule, while the negative chloride ion is attracted to the slightly positive hydrogen atoms.
Please help I’m soo confused what do you think might account for these similar properties? Explain
Answer:
i wonder...................
Explanation:
what is the answer ??z???????
Answer:
Females
Explanation:
Hope that helps
Answer:
The answer may be no characters
If I'm right or wrong plz reply to me
Write the net ionic equation for the reaction that occurs, if any, when gold is placed in a solution of hydrobromic acid
Answer:
ionic salt MX2
Explanation:
Atoms from an element in group IIA are allowed to react with atoms from an element in group VIIA. What type of compound is likely to form
elements from IIA are alkali earth metals (M) and need to lose
2 e^1- to become stable as M^2+
elements from VIIA ar halogens (X) and need to gain 1 e^1-
to become stable so one M^2+ combines with 2 X^1- to make
an ionic salt MX2
When a person goes on a diet, do they really want to lose weight or mass?
Need answer asap
Answer:
Cutting calories will help you lose weight. But dieting alone can strip away muscle along with body fat. Research suggests that as much as 25 per cent of weight lost by dieters is from muscle. And that's not a good thing.
Explanation: