Question

section 3.2 changes in matter
in your textbook, read about physical change and chemical change.
what kinds of changes do these words indicate? write each word under the correct heading. use each word only once.
boil crumple crush explode
burn ferment freeze grind
condense melt oxidize rot
corrode rust tarnish vaporize
physical change
1.
2.
3.
4.
5.
6.
7.
8.
chemical change
9.
10.
11.
12.
13.
14.
15.
16.
for each item in column a, write the letter of the matching item in column b.
column a column b

1. the new substances that are formed in a chemical reaction a. chemical change
2. a chemical reaction that involves one or more substances changing into new substances b. reactants
3. shows the relationship between the reactants and products in a chemical reaction c. products
4. states that mass is neither created nor destroyed in any process d. chemical equation

e. law of conservation of mass

1. the starting substances in a chemical reaction

answer the following question. write an equation showing conservation of mass of reactants and products.

1. in a laboratory, 178.8 g of water is separated into hydrogen gas and oxygen gas. the hydrogen gas has a mass of 20.0 g. what is the mass of the oxygen gas produced?

Explanation:

Step1: Define physical and chemical changes

Physical changes alter physical properties without changing the substance's identity. Chemical changes result in new substances.

Step2: Categorize the words

Physical Change: boil, condense, crumple, crush, freeze, grind, melt, vaporize
Chemical Change: burn, corrode, ferment, oxidize, explode, rot, rust, tarnish

Step3: Match column A - B

1. The new substances that are formed in a chemical reaction - c. products
2. A chemical reaction that involves one or more substances changing into new substances - a. chemical change
3. Shows the relationship between the reactants and products in a chemical reaction - d. chemical equation
4. States that mass is neither created nor destroyed in any process - e. law of conservation of mass
5. The starting substances in a chemical reaction - b. reactants

Step4: Solve for oxygen gas mass

According to the law of conservation of mass, the mass of reactants equals the mass of products. Let the mass of oxygen gas be $x$. The mass of water (reactant) is equal to the sum of the mass of hydrogen gas and oxygen gas (products). So, $178.8=20.0 + x$.

Step5: Isolate $x$

Subtract 20.0 from both sides of the equation: $x=178.8 - 20.0$.
$x = 158.8$ g

Answer:

Physical Change: boil, condense, crumple, crush, freeze, grind, melt, vaporize
Chemical Change: burn, corrode, ferment, oxidize, explode, rot, rust, tarnish

1. c. products
2. a. chemical change
3. d. chemical equation
4. e. law of conservation of mass
5. b. reactants
6. 158.8 g