Answer:
d. There are two moles of hydroxide for each mole of these compounds.
Explanation:
calcium hydroxide, strontium hydroxide, and barium hydroxide all have two hydroxide compunds. the difference between each of these compounds is they all contain a different element along with hydroxide.
What has the smallest mass,proton neutron or electron ?
Explanation:
Hey there!!
The answer is Electrons.
Electrons are the small part of an atom that revolves around the nucleus of an atom.
Hope it helps..
Which of the following would a chemist be most likely to study? A. what happens when a moving car comes to a stop B. what happens when iron rusts in the presence of water C. what happens when ice melts to form liquid water D. what happens when light reflects from a shiny surface
Answer:
B. what happens when iron rusts in the presence of water
Explanation:
1. What is the name of the covalent compound CCl4?2. What is the name of the covalent compound N2O5?
The name of the covalent compound CCl₄ is carbon tetracloride while that of N₂O₅ is dinitrogen pentoxide.
What is a covalent compound?Covalent compound has a covalent bond which is defined as a type of bond which is formed by the mutual sharing of electrons to form electron pairs between the two atoms.These electron pairs are called as bonding pairs or shared pair of electrons.
Due to the sharing of valence electrons , the atoms are able to achieve a stable electronic configuration . Covalent bonding involves many types of interactions like σ bonding,π bonding ,metal-to-metal bonding ,etc.
Sigma bonds are the strongest covalent bonds while the pi bonds are weaker covalent bonds .Covalent bonds are affected by electronegativities of the atoms present in the molecules.Compounds having covalent bonds have lower melting points as compared to those with ionic bonds.
Learn more about covalent compound,here:
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what is the first step to solving a problem ?
Measured value 28.7053 cm, which has six significant figures. Round the measurement to five significant figures
Answer:
28.705 cm
Explanation:
Hello,
In this case, for rounding the number to five significant figures we must "cut" it at 5 so we hide the 3, therefore it turns out:
28.705 cm.
Moreover, we must realize that since such 3 is less than five, we do not modify the previous five to six, case which would happen if that three has changed to five or more.
Regards.
what is the mass of an electron is
Answer:
the rest mass of an electron is 9.1093837915
Answer:
Fundamental properties. The invariant mass of an electron is approximately 9.109×10−31 kilograms, or 5.489×10−4 atomic mass units. On the basis of Einstein's principle of mass–energy equivalence, this mass corresponds to a rest energy of 0.511
What kind of substances can you not heat on a Bunsen burner?
Answer:
Substances which are non heat-resistant and volatile organic liquid with flammable vapor.
Explanation:
Bunsen Burner are used as a source of fire in the laboratory for heating up substances. Extra care however should be taken during heating in order to prevent fire or other forms of accidents.
Heating of mind heat resistant substances should be frowned at as the substances may get heated up and melt thereby exposing the liquid substances which may be flammable to fire thereby causing fire outbreak.
Heating of volatile organic liquid with flammable vapor should also be discouraged to prevent fire accidents.
What is the term for "anything that takes up space and has mass"?
O A. Electron
B. Water
O c. Matter
O D. Atom
SUBN
Pre-lab Assignment
1. Student A measures an object and records a value of 1.5 cm. Student B measures the same object
and records a value of 1.50 cm. They have both done their measurements correctly. Why do these
measurements differ?
a. They aren't different.
b. Person A used a ruler with markings every 0.1 cm. Person B used a ruler with markings every
0.01 cm.
c. Person A used a ruler with markings every 1 cm. Person B used a ruler with markings every 0.1
cm.
d. Person A rounded their measurement.
2. When multiplying or dividing measured numbers, we use the measurement with the least number of
significant figures to determine the number of significant figures (sf) in our answer. For example:
3.5 cm x 4.75 cm - 17 cm? (even though the calculator gives 16.675) Solve the following problems
assuming all are measured numbers. Report the correct number of significant figures.
a. 7.00 x 15.00 =
b. 40.2.1.901 =
c. (0.003)(13.2) =
d. 1.590+ 0.3975 =
Answer:
1. d. Person A rounded their measurement
2) a. 105.
b. 76.4
c. 0.04
d. 1.988
Explanation:
1. Measuring an object is done with the least precise one. Person A recorded 1.5cm while Person B recorded 1.50cm of the same object. This measurement differs in the sense that Person A rounded up their measurement to 2 significant figures (1.5) while Person B recorded their answer as three significant figures (1.50).
2. During multiplication and division, the result is written as the measurement in the lowest significant figure.
a. 7.00 x 15.00 = 105. Calculator showed 105.00, which is 5 s.f (two zeros after decimal point are significant). The least significant figure is 3, hence 105.00 is rounded up to 105.
b. 40.2.1.901 = 76.4; The calculator answer of this operation is 76.420200 but since the lowest significant figure is 3. We round up our answer to 3 s.f i.e. 76.4
c. (0.003)(13.2) = 0.04. For this operation, calculator answer is 0.0396, however, the lowest significant figure in the question is 1 i.e. 0.003. Note that the two zeros before 3 are insignificant. Hence, our answer will be rounded up to 1 s.f i.e. 0.04
d. 1.590+ 0.3975 = 1.988. the calculator answer to this operation is 1.9875. However, the least significant figure in the question is 4 i.e. 1.590. hence, the answer will be rounded up to 4 s.f which is 1.988.
please answer this question
Answer:
false, true, false - In reality stirring increases the speed of dissolving.
Answer:
False
True
False
Explanation:
1.It does take the shape of the container (has cohesive and adhesive properties)
2. It is a good solvent as in it, lots of salts are able to dissolve.
3. Stirring increases the speed of dissolving.
5. Three solution A, B and C have pH 2, 8 and 7 respectively.
A. Which one of these will turn blue litmus paper into red.
B. Which one of these will turn china rose indicator into green
C. Which one of these will not change colour of any indicator
Answer:
A. The solution with a pH of 2 will turn the litmus paper red
B. The solution with a pH of 8 will turn the China rose indicator green
C. The solution with a Ph of 7 will not change the color of the blue litmus indicator or of the China rose indicator
Explanation:
Blue litmus paper will only change color if it is dipped into an acidic mixture which turns it red. It will not change color at all in a basic or neutral Ph solution.
China rose turns dark pink in an acidic solution and green in a basic solution. However it has no change in color with a neutral solution.
If you stacked Avogadro's number of pennies one on top of the other on Earth's surface, how far would the stack extend (in kilometers)? [For comparison, the sun is about 150 million km from Earth and the nearest star (Proxima Centauri) is about 40 trillion km from Earth.] Express your answer using four significant figures.
Answer:
Avogadro number of pennies will extend to a distance of 6.02 * 10¹⁷ km
Note: The question is missing some parts. The complete question is as follows;
A penny has a thickness of approximately 1.0 mm . If you stack ed Avogadro's number of pennies one on top of the other on Earth 's surface, how far would the stack extend (in km)? [For comparison, the sun is about 150 million km from Earth and the nearest star (Proxim a Centauri) is about 40 trillion km from Earth.]
Explanation:
Avogadro number = 6.02 * 10²³
thickness of a penny = 1.0 mm
I mm = 0.001 m
Thickness of Avogadro number of pennies stacked one upon another will be:
6.02 * 10²³ * 0.001 m = 6.02 * 10²⁰ m
Distance in km;
1 m = 0.001 km
therefore, 6.02 * 10²⁰ m = 6.02 * 10²⁰ * 0.001 km = 6.02 * 10¹⁷ km
Avogadro number of pennies will extend to a distance of 6.02 * 10¹⁷ km
A beaker cannot be used for measuring the volume of a liquid because _____.
Answer:
Data obtained can't be accurate.
Explanation:
A beaker can't be used for measuring the volume of a liquid because they did not calculate volume of a liquid accurately and precisely. The marks present on the beaker are not accurate, it is just an estimate so by measuring the volume of any liquid using beaker give us a false data so that's why beaker are not used for the measurement of a volume.
Convert a density of 1,235 kg/m3 to grams per cubic centimeter
Answer:
Density, [tex]d=1.235\ g/cm^3[/tex]
Explanation:
It is given that, the density is 1,235 kg/m³.
We need to convert the density to g/cm³.
We know that,
1 kg = 1000 g
1 m = 100 cm
[tex]1235\ kg/m^3=1235\ \dfrac{kg}{m^3} \\\\=1235\times \dfrac{1000\ g}{(100\ cm)^3}\\\\=1.235\ g/cm^3[/tex]
So, the density is [tex]1.235\ g/cm^3[/tex].
Normal human body temperature is 98.6 °F. This is equivalent to °C or K is :___________.
Answer:
74ifhdyteuyteutyruf
a cube is 4 cm on each size .what is it’s volume?
Answer:
64cm^3
Explanation:
[tex]s = 4cm\\V = s^3\\\\V = 4^3\\V =4\times 4\times 4\times 4\\Volume = 64cm^3[/tex]
Calculate the PE of an object that has a mass of 2kg that is resting on a 6m table. HELP ME PLEASE I REALLY NEEEEED HELP!!!! 21 POINTS PLEASSEEEE
Answer:
Calculate the unknown variable in the equation for gravitational potential energy, where potential energy is equal to mass multiplied by gravity and height; PE = mgh. Calculate for different gravity of different enviornments - Earth, the Moon, Jupiter, or specify your own. Free online physics calculators, mechanics, energy, calculators.
Explanation:
Why is important to only change one variable in a controlled experiment
A variable within a scientific experiment is something that is changed (i.e. it varies). There should be only one manipulated variable within a scientific experiment so that the experimenter can be certain it is this variable which causes a pattern in the resultant data, if any exists at all.
HOPE IT HELPS PLZ BRAINLIEST
Does pineapple belong in pizza
Answer:
No no no and no no no no no no
Answer:
This is quite a controversial question ahaha. Personally, I think pineapple on pizza is good sometimes. depends on the day though.
Explanation:
To me it is a good combination of sweet and salty. The pineapple is also pretty refreshing.
Calculate the volume, in milliliters, of a 0.470 M KOH solution that should be added to 5.250 g of HEPES (MW = 238.306 g/mol, pKa = 7.56) to give a p
Answer:
17.13mL
Explanation:
Complete question:
to give a pH of 7.32.
Hepes is a weak acid. When HEPES reacts with KOH its conjugate base, HEPES⁻ is produced:
HEPES + KOH → HEPES⁻
Now when you have in solution both the weak acid and conjugate base a buffer is produced. The equation that relates pKa and pH of a buffer is H-H equation:
pH = pKa + log [HEPES⁻] / [HEPES]
Where [] could be taken as the moles of each specie.
Replacing:
7.32 = 7.56 + log [HEPES⁻] / [HEPES]
-0.24 = log [HEPES⁻] / [HEPES]
0.57544 = [HEPES⁻] / [HEPES] (1)
Now, moles of 5.250g of HEPES is:
Mass HEPES:
5.250g * (1mol / 238.306g) = 0.02203 moles HEPES.
That means:
0.02203 moles = [HEPES⁻] + [HEPES] (2)
Replacing (2) in (1):
0.57544 = 0.02203 moles - [HEPES] / [HEPES]
0.57544[HEPES] = 0.02203 moles - [HEPES]
1.57544[HEPES] = 0.02203 moles
[HEPES] = 0.01398 moles HEPES.
And [HEPES⁻] = 0.02203 moles - 0.01398 moles =
0.00805 moles of HEPES⁻
As HEPES⁻ is produced from HEPES and KOH, if we add 0.0805 moles of KOH, we will have in solution 0.00805 moles of HEPES⁻ and 0.01398 moles of HEPES.
To obtain 0.00805 moles of KOH from a 0.470M KOH, you need to add:
0.00805 moles KOH * (1L / 0.470mol) = 0.01713L of 0.470M KOH =
17.13mLChocolate candy melting in your hand is what type of heat transfer
PLEASE HELP WITH PAGE 1 FOR QUESTIONS 1, 2, 3 WITH THE GRAPHING THANK YOU.
The TV weather forecaster announces that one location has a 30% chance of rain tomorrow and a 35% chance of hail. What is the probability that it will rain or hail in this location?
Answer: 65%
Explanation:
When in probability and the outcome is mutually exclusive which means that either one or the other will happen then the probabilities of the events should be added up.
P(A or B) = P(A) + P(B)
P(Rain or Hail) = P(Rain) + P(Hail)
P(Rain or Hail) = 30% + 35%
P(Rain or Hail) = 65%
1. Why is it important to know the names and appearance of lab equipment before doing laboratory work? 1. So you will score higher on the lab test. 2. So you quickly obtain your laboratory supplies before lab. 3. So you can follow the lab instructions clearly. 4. So you can make sure everything has been cleaned before beginning the lab procedure.
Answer:
1. because what if you do a incorrect ion? it would be all wrong! 2. you dont get it quickly because! you might get the wrong equipment. 4. yep! no food or drinks!
Explanation:
hope this helps ☻︎
How many protons and neutrons does iron-56 have? Question 10 options: 26 protons and 56 neutrons 26 protons and 26 neutrons 30 protons and 56 neutrons 26 protons and 30 neutrons
Answer:
Protons: 26
Neutrons: 30
Explanation:
A protein has an isoelectric point (pI) of 9. Which of the following statements best describes the state of this protein in aqueous solution at pH 7?
A. The side chains of the protein's basic residues will be mostly uncharged
B. The side chains of the protein's acidic residues will be mostly protonated
C. The protein will have no net charge
D. The protein will have a net positive charge
E. The protein will have a net negative charge
Answer:
The correct option is D
Explanation:
From the question we are told that
The pH of the aqueous solution is [tex]pH = 7[/tex]
The isoelectric point is [tex]pl = 9[/tex]
From the data given we see that the
[tex]pH[/tex] is below [tex]pl[/tex]
So the protein will have a net positive charge
A protein has an isoelectric point (pI) of 9, the statement which best describes the state of this protein is that the protein will have a net positive charge.
What is isoelectric point?Isoelectric point of any susbatnce is the pH of the substance where net charge on that substance will be zero, i.e. no. of positive charged ions will equal to the number of negative charged ions.
In the question it is given that value of isoelectric point (pl) of protein is 9 and given value of pH is 7. It means that isoelectric point is higher that given pH so the protein molecule should bear a positive charge on it. If pH value is greater than pl value then molecule will bear a negative charge.
Hence option (D) is correct.
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1. Sketch the structures of maleic and fumaric acids. What is the structural relationship between the two? 2. How does the structure/isomerism of each acid affect its physical properties?
Answer:
See explanation
Explanation:
The structures of maleic and fumaric acids are shown in the image attached to this answer.
We can easily see that maleoc and fumaric acids are geometric isomers of each other. They differ only in the orientation of the -COOH group about the C=C double bond.
Maleic acid is less stable than fumaric acid as shown by their respective heats of combustion. This is expected since maleic acid is the cis-isomer with more steric repulsion than the trans-isomer.
Maleic acid is more soluble than fumaric acid and also has a lower melting point than fumaric acid.
Question: In experiment your teacher has provided you with a sample of sandy, salty, ocean water and
asked you to separate the components of the mixture. In no more than four sentences, state if the
sample is a homogeneous or heterogeneous mixture, with supporting evidence, and describe how you
would accomplish the task.
Answer:
Explanation:
Homogeneous mixture is a mixture in which the components of the mixture are in the same proportion throughout any sample extracted from the mixture while an heterogeneous mixture is a mixture in which the components of the mixture differ in term of proportion when different samples of the mixture are extracted and compared.
For example, a sandy water will have some parts (usually the bottom) of the mixture with more sand than other parts of the mixture, hence, it (sandy water) is a heterogeneous mixture. While salty and ocean water has it's salt dissolved in the same proportion throughout the water in the mixture, hence salty and/or ocean water is a homogeneous mixture.
Sandy water can be separated by filtration (i.e using a filter paper to separate the sand from the water when the mixture is poured over a filter paper) while salty and ocean water can be separated by distillation (i.e boiling of the mixture so the water molecules can boil and move through a tube as gas or steam into another container where they are cooled and converted back to liquid or water while leaving the solid salt component of the mixture in the boiling tube).
Water drops that fall on a smooth surface tend to form rounded drops or beads. Then, if you touch a piece of paper to the drop, water appears to move up into the paper on its own. Identify and describe the properties of water that explain this phenomenon.
Answer:
Surface tension
Capillary action
Explanation:
Surface tension is the force acting along the surface of the liquid causing the liquid surface to behave like a stretched elastic skin. Surface tension causes the water drops that fall on a smooth surface to form rounded drops or beads.
If you touch a piece of paper to the drop, water appears to move up into the paper on its own due to capillarity. Capillarity is the tendency of a liquid to rise or fall in a narrow tube.
When you calculate apercent recovery you may find sometimes that it islarger than 100%. Assuming this is NOT due to errors associated with zeroing the balance, subtracting the weight of the watch glass or weigh paper, or inaccuracies in the balance calibration, suggest a possible reason for this.
Answer:
Presence of impurities in the product.
Explanation:
Laboratory experience has shown that the percent yield obtained from a reaction may be greater than 100% if the product obtained from the reaction contains impurities that causes its mass to be greater than it actually would be if the product was pure.
A typical impurity that may be present in a product is the solvent used. This can be removed by evaporation of the solvent or by washing the product thoroughly.
Reaction of solid products with gases may also increase the percentage yield above 100%.