CHEMISTRY HIGH SCHOOL

1 Which best defines concentration?A ratio that describes the amount of solute divided by the amount of solvent or solution
B ratio that describes the amount of solvent or solution divided by the amount of solute
C ratio that describes the mass of solute divided by the mass of solvent
D ratio that describes the amount of solvent in a solution

2 Which contributes to the dissolution of sugar in water?
A the dissociation of an ionic compound in water
B a strong pull of water molecules on an ionic compound
C the dissociation of a polar covalent compound in water
D a strong pull of water molecules on a polar covalent compound

Answers

Answer 1

Answer:

These are two questions and two answers.

Question 1: Which best defines concentration?

Answer: option A, ratio that describes the amount of solute divided by the amount of solvent or solution

Explanation:

There are many different measures of concentration: percent, molarity, molality, mole fraction are some examples.

All of them express the ratio of solute to solvent or solution, in different kind of units, may be mass, number of moles, or volume.

Molarity is number of moles of solute per liter of solution. Molality is number of moles of solute per kg of solvent.

So, as you see it is always a ratio of the amound of solute, but it is not a fixed unit.

Question 2. Which contributes to the dissolution of sugar in water?

Answer: option D, a strong pull of water molecules on a polar covalent compound.

Explanation:

Sugar is not a ionic compound so it does not dissociate.

Sugar is a molecule, so it remains as such in solution.

Sugar is polar, so it can be dissolved in water that is a polar solvent (like dissolve like, is the rule).

The dissolution is explained by the fact that the pull exerted by the molecultes of solvent on the molecules of solute, is greater than the pull that the molecules of solute extert among themselves.

That permits the molecules of solvent surround the molecules of solute and get them appart of the solid substance to form the aqueous solution.

Answer 2

Answer:

Concentration is the ratio that describes the amount of solute divided by the amount of solvent or solution; option A

The dissociation of sugar in water is due to a strong pull of water molecules on a polar covalent compound; option D

What is concentration of a solution?

Concentration of a solution is the amount of solute present in a given volume of solution.

Thus, concentration is the ratio that describes the amount of solute divided by the amount of solvent or solution.

The dissolution of sugar in water forms a sugar solution.

Sugar is a polar covalent molecule. The dissociation of sugar in water is due to a strong pull of water molecules on a polar covalent compound.

Learn more about polar compounds at: brainly.com/question/1433127

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What is the symbol for an atom containing 20 protons and 22 neutrons?
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Hydrogen has three isotopes, 1H, 2H, and 3H. What is the difference between these three isotopes?A. The number of protons ranges from 1 to 3.
B. The number of electrons ranges from 1 to 3.
C. The number of neutrons ranges from 0 to 2.
D. The number of protons ranges from 0 to 2.

Answers

The correct answer is C.

A substance is said to exhibit isotopy if the number of proton and neutron in the nucleus of the atom differs, whille the number of proton and electron are the same. Hydrogen has three isotopes and each of the isotopes has different number of neutron. Hydrogen 1 has no neutron but have 1 proton, hydrogen 2 has 1 neutron and 1 proton and hydrogen 3 has 1 proton and 2 neutrons.

C... The number of neutrons ranges from 1H with 0 neutron, 2H with 1 neutron and 3H with 2 neutrons.

An atom of any element must contain(1) an equal number of protons and neutrons
(2) an equal number of protons and electrons
(3) more electrons than neutrons
(4) more electrons than protons

Answers

An atom of any element must contain "(2) an equal number of protons and electrons" but it should be noted that atoms can borrow electrons from one another.

An atom (which by definition is neutral) should have (2) an equal number of protons and electrons.
If the number of protons and electrons are not equal, it becomes an ion.The number of protons and neutrons can vary widely depending on what the substance is and depending on the isotopes.

How many grams of sodium sulfide can be produced when 45.3 g Na react with 105 g S? Unbalanced equation: Na + S → Na2S

Show, or explain, all of your work along with the final answer.

Answers

The chemical reaction would be as follows:

2Na + S → Na2S

We are given the amount of the reactants to be used in the reaction. We use these to calculate the amount of product. We do as follows:

45.3 g Na ( 1 mol / 22.99 g ) = 1.97 mol Na
105 g S ( 1 mol / 32.06 g ) = 3.28 mol S

The limiting reactant would be Na. We calculate as follows:

1.97 mol Na ( 1 mol Na2S / 2 mol Na ) (78.04 g / mol ) = 76.87 g Na2S produced

What is the percent yield of ferrous sulfide if the actual yield is 220.0g and the theoretic yield is 275.6?

Answers

ANSWER yield = 79.83%

Which statement describes a chemical property of the element magnesium?(1) Magnesium is malleable.
(2) Magnesium conducts electricity.
(3) Magnesium reacts with an acid.
(4) Magnesium has a high boiling point.

Answers

Answer: option 3) magnesioum reacts with an acid.

Justification:

1) Malleability, conduction of electricity, and boiling point are physical properties.

2) Maleability is the ability to be transformed into foil. It is just a change in form. So, it is a physical property.

3) The metals conduct electricity in virtue of the array of the atoms, which permtis the flow of the electrons, but it does not involve a chemical change, so it remains being a physical proerty.

4) Boling point is the temperature at which a substance passes from liquid state to gas state, which are just different forms of the same substance. So, it is other physical property.

5) Reaction with an acid is indeed a chemical transformation: the metal (magnessium) will form a chemical bond with some spieces of the acid to form a new compound. This is a chemical reaction in virtue of the chemcial properties of the substance (its ability to react with acids)

Magnesium reacts with an acid.

Which is the correct expression for Keq when the chemical reaction is as follows:N2 + 3H2 2NH3.

Answers

Answer : The expression for equilibrium constant will be,

$K_(eq)=\fac{[NH_3]^2}{[N_2][H_2]^3}$

Explanation :

Equilibrium constant : It is defined as the number of ratio of the concentration between the products and the reactants at equilibrium.

The equilibrium reaction is,

$aX+bY\rightleftharpoons cW+dZ$

The general expression for equilibrium constant will be,

$K_(eq)=([X]^a[Y]^b)/([W]^c[Z]^d)$

The given balanced chemical reaction will be,

$N_2+3H_2\rightleftharpoons 2NH_3$

The expression for equilibrium constant will be,

$K_(eq)=([NH_3]^2)/([N_2][H_2]^3)$

The expression of the Keq is [NH3]2/([N2][H2]3). The common formula of reaction: ax+by=cz is Keq - [z]c/([x]a*[y]b). Remember to use a balanced chemical reaction.

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