Conservation of Mass and Chemical Equations/Reactions

Question 1

What does a chemical change involve?

Answer 1

The reaction of a substance to produce a new substance.

Question 2

True or False: A chemical change always involves the conversion of substances, called reactants, into other substances, called products.

Answer 2

True

Question 3

Reactant Definition

Answer 3

A pure substance that undergoes a chemical change.

Question 4

Product Definition

Answer 4

A pure substance that is formed in a chemical change; the properties of the product are different from the properties of the reactants.

Question 5

True or False: The properties of the products are different from the properties of the reactants, even though the products have the same atoms as the reactants.

Answer 5

True

Question 6

In a chemical reaction, what is conserved (they are neither created nor destroyed)?

Answer 6

Atoms

Question 7

The atoms, however, are rearranged to form what?

Answer 7

New substances

Question 8

True or False: A chemical reaction is one or more chemical changes that occur at the same time.

Answer 8

True

Question 9

Chemical Reaction Definition

Answer 9

A process in which new substances with new properties are formed.

Question 10

What does the Law of Conservation of Mass state?

Answer 10

In a chemical reaction, the total mass of the products is always the same as the total mass of the reactants.

Question 11

What is used to represent a chemical reaction?

Answer 11

A chemical equation

Question 12

Chemical Equation Definition

Answer 12

A representation of what happens to the reactants and products during a chemical change.

Question 13

What are the three forms of chemical equations?

Answer 13

-A word equation
-A skeleton equation
-A balanced chemical equation

Question 14

Explain what a word equation includes

Answer 14

-The name of each reactant is written to the left of an arrow;
-The name of each product is written to the right of the arrow
-A plus sign on the reactant side means “reacts with”
- A plus sign on the product side means “and”;
-The arrow stands for “yields or reacts to produce.”

Question 15

Explain what a skeleton equation includes

Answer 15

-Shows the reactants and products of a reaction, but does not provide information about the chemical composition of the substances;
-Replacing the words with chemical formulas produces a skeleton equation.

Question 16

Explain what a balanced chemical equation includes

Answer 16

-Demonstrates the law of conservation of mass, which requires the same number of atoms of each element to appear on both sides of a chemical equation;
-A coefficient is a number that is placed in front of a chemical formula in a balanced equation to show how many units of the substance are involved in the reaction.

Question 17

Coefficient Definition

Answer 17

A number that is placed in front of a chemical formula in a balanced chemical equation.

Question 18

Work on Worksheets under “Chemistry Unit Test Review” to practice the Law of Conservation of Mass, Balancing Chemical Equations and Textbook Questions 1-3 and 6-8 on page 158

Answer 18

Depending on Comfort Level

Question 19

Electronegativity Definition

Answer 19

A measure of the tendency of an atom to attract a shared pair of electrons.

Question 20

The measure of electronegativity is affected by the atomic number of the atom as well as the relative distance between the _______ and the _________ _______

Answer 20

Nucleus; Valence Shell

Question 21

True or False: As the atomic number increases, so does the distance between the nucleus and the valence shell.

Answer 21

True

Question 22

A large electronegativity difference between two atoms will lead to an ________ bond.

Answer 22

Ionic

Question 23

A small electronegativity difference between two atoms will lead to a ___________ bond.

Answer 23

Covalent