Question

8. How does a balanced chemical equation demonstrate the Law of Conservation of Mass?(1 point)
Responses

it shows that no atoms have been gained or lost during the reaction
it shows that no atoms have been gained or lost during the reaction

it shows that only physical changes follow the Law of Conservation of Mass
it shows that only physical changes follow the Law of Conservation of Mass

it shows that the properties of elements stay the same after the reaction
it shows that the properties of elements stay the same after the reaction

it shows that all compounds remain bonded after the reaction
it shows that all compounds remain bonded after the reaction
Question 9
9. Sodium reacts with chlorine to form the compound sodium chloride, or salt. The chemical formula below shows how the two elements combine into a compound.

2Na + Cl2 → 2NaCl

If the total mass of the reactants is 58.44 amu, what will be the total mass of the products?

(1 point)
Responses

60 amu
60 amu

29.22 amu
29.22 amu

116.88 amu
116.88 amu

58.44 amu
58.44 amu
Question 10
10. Which lab procedure could be used to demonstrate that matter is conserved during a physical change? (1 point)
Responses

Find the mass of a piece of ice. Let the ice melt. Find the mass of the liquid water.
Find the mass of a piece of ice. Let the ice melt. Find the mass of the liquid water.

Find the mass of a raw egg. Cook the egg. Find the mass of the cooked egg.
Find the mass of a raw egg. Cook the egg. Find the mass of the cooked egg.

Find the mass of a cup of water. Boil the water. Find the mass of the water that remains.
Find the mass of a cup of water. Boil the water. Find the mass of the water that remains.

Find the mass of an apple. Cut the apple and remove the core. Find the mass of the remaining apple.
Find the mass of an apple. Cut the apple and remove the core. Find the mass of the remaining apple.
Question 11
11. One molecule of bromine (Br2) and two molecules of potassium chloride (KCl) combine in a reaction. How many atoms are in the products?(1 point)
Responses

two
two

six
six

four
four

three
three
Question 12
12. Use the unbalanced chemical equation to answer the question.

2NaHCO3 → Na2CO3 + CO2

Which of the following can be added to the products to balance the equation?
(1 point)
Responses

O2
O 2

CH2OH
CH 2 OH

H2
H 2

H2O

Answer 1

Here are the answers to the questions you've provided:

**Question 8:**
How does a balanced chemical equation demonstrate the Law of Conservation of Mass?
- **Response:** it shows that no atoms have been gained or lost during the reaction.

---

**Question 9:**
If the total mass of the reactants is 58.44 amu, what will be the total mass of the products?
- **Response:** 58.44 amu.

---

**Question 10:**
Which lab procedure could be used to demonstrate that matter is conserved during a physical change?
- **Response:** Find the mass of a piece of ice. Let the ice melt. Find the mass of the liquid water.

---

**Question 11:**
How many atoms are in the products when one molecule of bromine (Br2) and two molecules of potassium chloride (KCl) combine?
- **Response:** six. (1 molecule of Br2 has 2 Br atoms + 2 molecules of KCl have 2 K + 2 Cl = 2 + 2 + 2 = 6 atoms total)

---

**Question 12:**
Which of the following can be added to the products to balance the equation?
2NaHCO3 → Na2CO3 + CO2
- **Response:** H2O. (The addition of water can help balance the released carbon dioxide and stabilize the products.)

Feel free to ask if you need anything else!