Conservation of Mass Review

EXPERIMENT #1

REACTANT(S) ------> PRODUCT(S)

48.6g Magnesium + 32.0g Oxygen ------> 80.6g Magnesium Oxide.

Does this experimental data support the Law of Conservation of Mass?

• yes

• no

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EXPERIMENT #2

REACTANT(S) ------> PRODUCT(S)

____g Magnesium + 16.0g Oxygen ------> 40.3g Magnesium Oxide

a. Based on the Law of Conservation of Mass, predict the minimum amount of magnesium that will react with all 16.0 grams of oxygen to produce 40.3 grams of

magnesium oxide. _________________

• 40.3g

• 16.0g

• 24.3 g

• 56.3

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NGSS.MS-PS1-5

EXPERIMENT #3

REACTANT(S) ------> PRODUCT(S)

12 .2 g Magnesium + 8.0g Oxygen ------> _____Magnesium Oxide

Assuming that magnesium and oxygen will react completely with one another, predict the mass of magnesium oxide that will be produced. _________

• 12.2 g

• 8.0 g

• 20.2 g

• 4.2g

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NGSS.MS-PS1-2

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EXPERIMENT #4

If the cap had been removed during the reaction (open system), would there still be 44g of Product in the jar?

• No, some of the substance was lost out of the container as a gas

• Yes, mass can't be destroyed

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NGSS.MS-PS1-5

A solid mass of 25 g is mixed with 60 g of a solution. A chemical reaction takes place in an open system and a gas is produced. The final mass of the mixture is 75 g. What is the mass of the gas released?

• 15g

• 10g

• 25g

• 75g

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A scientist mixes 25 grams of Reactants, how many grams of products should I have (in a closed system)?

• 25g

• 50g

• 10g

• 15g

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NGSS.MS-PS1-5

A scientist mixed 100 grams of salt into a 500 grams of water. How many grams of salt water did I make?

• 500g

• 400g

• 600g

• 700g

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

• The heat caused the compound to become less dense

• The reaction gave off more heat than was added

• Some of the lighter atoms were converted to energy

• One of the reaction products was a gas.

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NGSS.MS-PS1-2

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Matter can be classified as an element, a compound, or a mixture. The elements sodium (Na) and chlorine (Cl) react with each other to form the compound sodium chloride (NaCl), also known as table salt. The reaction between sodium and chlorine releases energy. This causes the temperature of the substances in the reaction to increase. When table salt dissolves in water a solution is formed, which is a type of mixture.

A reaction between 46 grams of sodium (Na) and 71 grams of chlorine (Cl) formed table salt. Which of the following measurements would most likely be the mass of the table salt?

• 25g

• 110g

• 71g

• 117g

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NGSS.MS-PS1-2

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How does the total amount of matter before a chemical reaction compare to the total amount of matter after the reaction?

• The amount of matter is greater before the reaction.

• The amount of matter is greater after the reaction

• The amount of matter before and after the reaction is the same.

• There is no relationship between the amount of matter before and after the reaction.

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