SC 7 N 1 4

In order to ensure our experiment is valid we must have _________ variables

• Constant/Control

• Operational

• Independent

• Dependent

How does the concept of conservation of mass apply to chemical reactions?

• the reactants and products have exactly the same atoms

• the reactants and products have exactly the same molecules

• the change in the amount of matter is equal to the change in energy

• the change in the amount of matter is only a small percentage of the total mass

Tags

NGSS.MS-PS1-5

Which BEST describes how to balance the chemical equation shown below?

• add the coefficient 2 before the Mg on both sides

• add the coefficient 2 before the O₂ on the left side

• add the coefficient 2 before the Mg on the left side

• add the coefficient 2 before the MgO on the right side

Tags

NGSS.MS-PS1-5

Freddy mixed 10 grams of a powdery substance with 200 grams of an acid solution. A bubbly solution weighing 205 grams was formed. Which BEST explains why the mass of the new solution doe not equal the mass of the reactants?

• the other 5 grams changed color

• the other 5 grams created a precipitate

• the other 5 grams were released as gas

• the other 5 grams weighed less in the acid

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which statement is BEST supported by the following equation:

• CO₂ is made from the chemical reaction

• No new compounds are made from this reaction

• O₂, oxygen gas, is needed to make the reaction start.

• The atoms rearrange in the chemical reaction so that glucose, C₆H₁₂O₆ is made

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

What is the total number of oxygen atoms on the product side of the equation below?

• 2

• 3

• 5

• 7

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-2

A piece of paper has a mass of 13 grams. When the paper is burned, a chemical change occurs and both smoke and ashes are produced. Based on the Law of Conservation of Mass, which statement is true?

• the smoke has a mass of 13 grams

• the ashes have a mass of 13 grams

• the smoke and ashes have a combined mass of 13 grams

• the smoke and the ashes have a combined mass less than 13 grams

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which is the BEST system to use when studying the Law of Conservation of Mass?

• a closed system to measure the mass of the reaction

• an open system to measure the mass of the reaction

• a large system to give the reaction space to occur

• a small system to closely observe the reaction

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A sealed test tube containing 5 grams of iron fillings and 10 grams of sulfur is heated until the material in the test tube glows bright red. Which is true about the reaction?

• the product will have a mass of 15 grams

• the product will have a mass less than 15 grams

• the product will have a mass more than 15 grams

• the mass of the product cannot be determined

Tags

NGSS.MS-PS1-5

Which is a balanced equation?

• CH₄ + O₂ ----> CO₂ + 2H₂O

• CH₄ + O₂ ----> 2CO₂ + H₂O

• CH₄ + 2O₂ ----> CO₂ + 2H₂O

• 2CH₄ + O₂ ---> CO₂ + 2H₂O

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5