Unit 3: Changes of Matter

At higher temperatures

• particles in an object have less energy
• particles in an object move faster
• a gas contracts

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NGSS.MS-PS1-4

Your teacher wants to demonstrate a chemical reaction. Which activity would BEST demonstrate a chemical reaction?

• Placing a metal in an acid to create a gas

• measuring the densities of liquid water and ice

• melting a solid piece of aluminum

• filling a balloon with helium gas.

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If reaction starts with 20g of reactants it should produce 

• a total of 40g of products
• a total of 10g of products
• a total of 80 g of products
• a total of 20g of products

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NGSS.MS-PS1-5

A student heated a 10 gram sample of a chemical in an open container. A chemical reaction occurred, and the mass of the sample was measured again. The mass of the sample was found to be less than before the reaction. Which of the following best explains the decrease in mass of the sample?

• The heat caused the chemical to become less dense.

• The reaction gave off more heat than was added.

• Some of the lighter particles were destroyed.

• Some of the particles escaped as a gas formed.

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NGSS.MS-PS1-2

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Anthony is performing an experiment. He adds 0.25 grams of baking soda to 5 grams of water and stirs. Anthony watches as the baking soda dissolves in the water. If Anthony weighs the water and baking soda solution, what will its mass be?

• 4.75 grams
• 5.0 grams
• 5.25 grams
• 7.5 grams

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NGSS.MS-PS1-2

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True or False

The mass of the reactants in a chemical equation must equal the mass of the products.

• True

• False

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NGSS.MS-PS1-5

According to the Law of Conservation of Mass, what happens to the wood and oxygen when it is burned?

• The wood disappears.

• It stays the same chemically.

• The atoms in the wood and oxygen rearrange and form smoke and ash.

• Nothing.

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NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of the following models best demonstrates the law of conservation of mass? 

• 
• 
• 
• 

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NGSS.MS-PS1-5

Suppose you have 15g of baking soda and mix it with 15g of vinegar. When they are combined they bubble and fizz a lot. The final solution has a mass of 25g. What happened to the "lost" 5g?

• it dissappears

• it is still there just not weighted

• it is in the gas that is formed

• nothing happened

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NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of the following is a sign that a chemical reaction has occurred?

• change in shape
• melting
• formation of a gas
• dissolving

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