Mass before and after

Question 1

Vinegar and baking soda are mixed in an OPEN cup on a balance. They fizz and 4 g of gas escapes into the air. The mass before was 295 g. What does the balance show after the fizzing stops?

Answer g

Question 2

A sealed bag of 140 g of ice is left until all the ice has melted. What is the mass of the bag of water now (ignore the bag)?

Answer g

Question 3

Rust forms on an iron nail. The rusty nail has MORE mass than the clean nail. Why?

• A. Rust is made from nothing.
• B. The nail grew longer.
• C. Rust is always heavier than anything.
• D. Oxygen from the air joined with the iron.

Question 4

Vinegar and baking soda are mixed inside a sealed plastic bottle on a balance. They fizz and make a gas. The mass before was 156 g. What is the mass after the fizzing stops?

Answer g

Question 5

140 g of water and 60 g of salt are stirred until the salt dissolves. What is the total mass?

Answer g

Question 6

A burning candle on a balance gets lighter. Has matter been destroyed?

• A. No, the balance is broken.
• B. No, the wax has turned into gases that escaped into the air.
• C. Yes, burning destroys matter.
• D. Yes, the flame eats the wax.

Question 7

Vinegar and baking soda are mixed inside a sealed plastic bottle on a balance. They fizz and make a gas. The mass before was 228 g. What is the mass after the fizzing stops?

Answer g

Question 8

A sealed bag of 125 g of ice is left until all the ice has melted. What is the mass of the bag of water now (ignore the bag)?

Answer g

Question 9

A sealed flask of water is weighed, heated until some water boils into steam, then weighed again with the lid still on. What happens to the mass?

• A. It goes down.
• B. It stays the same.
• C. It becomes zero.
• D. It goes up.

Question 10

Vinegar and baking soda are mixed in an OPEN cup on a balance. They fizz and 2 g of gas escapes into the air. The mass before was 265 g. What does the balance show after the fizzing stops?

Answer g

Question 11

A sealed bag of 275 g of ice is left until all the ice has melted. What is the mass of the bag of water now (ignore the bag)?

Answer g

Question 12

Why do scientists use a sealed container to show that mass is conserved in a reaction that makes a gas?

• A. So the gas turns into a liquid.
• B. So the reaction goes faster.
• C. So the gas cannot escape and every particle is still weighed.
• D. Because open containers break.

Question 13

Vinegar and baking soda are mixed in an OPEN cup on a balance. They fizz and 5 g of gas escapes into the air. The mass before was 196 g. What does the balance show after the fizzing stops?

Answer g

Question 14

85 g of sand and 25 g of iron filings are mixed together. What is the total mass?

Answer g

Question 15

Why do scientists use a sealed container to show that mass is conserved in a reaction that makes a gas?

• A. So the gas turns into a liquid.
• B. So the reaction goes faster.
• C. So the gas cannot escape and every particle is still weighed.
• D. Because open containers break.

Question 16

Vinegar and baking soda are mixed in an OPEN cup on a balance. They fizz and 5 g of gas escapes into the air. The mass before was 266 g. What does the balance show after the fizzing stops?

Answer g