Review of Matter in its interactions (S8P1b,c,d,f)

Mariana conducted an experiment where she burned a 5 g strip of magnesium metal in an open flame. The result was a 3.5 g white ash collected in a crucible, a bright white flame, and smoke. Was the law of conservation of matter upheld in Mariana's experiment?

• yes, because the missing mass was trapped by the closed system

  
  

• no, because the magnesium was burned so mass was not lost

  
  

• no, because mass decreased after the magnesium was burned

  
  

• yes, because the missing mass was released as smoke

  
  

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A saltwater solution is formed by dissolving 5 grams of salt in 100 grams of water. The solution is heated, and all of the water is boiled away. How much salt should be left behind?

• 2.5 grams

  
  

• 5 grams

  
  
  

• 95 grams

  
  

• 105 grams

  
  

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A hot copper cooking pot cools down to room temperature. What happens to the copper atoms as the pot cools?

• The copper atoms move more quickly.

  
  

• The speed of the copper atoms does not change.

  
  

  
  

• The copper atoms slow down but do not stop.

• The copper atoms slow down and stop moving.

  
  

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

A student is shown a simple model of particles that make up a gas, as shown below. 
How should the model be changed to show the particles of a liquid?

• Decrease the velocities of the particles, and decrease the space between the particles. 

  
  

• Increase the velocities of the particles, and increase the space between the particles. 

  
  

• Increase the velocities of the particles, and decrease the space between the particles. 

  
  

• Decrease the velocities of the particles, and increase the space between the particles. 

  
  

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-2

Your teacher burns a piece of steel wool in class, demonstrating the chemical property, flammability.

You are curious to see what other things can demonstrate chemical properties. Which of these does not demonstrate a chemical change?

• Burning sugar demonstrates a chemical change.

  
  

• The rusting of steel wool demonstrates a chemical change.

  
  

• Making soap by allowing fat to react with sodium hydroxide demonstrates a chemical change.

  
  

• Measuring the freezing point of different concentrations of salt water demonstrates a chemical change.

  
  

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Silver is a white metal and is an excellent conductor of heat and electricity. The density of silver is 10.49 g/cm³. Silver does not react with water but it does react with nitric acid. Silver tarnishes when exposed to air or light.

What is a physical property of silver?

• density

• tarnishes

• reacts with nitric acid

• does not react with water

Magnesium is a light silver metal. When it is burned in oxygen, it oxidizes in a bright white light. Magnesium oxide is a white powder. How can we be sure that burning magnesium in oxygen is a chemical reaction?

• A gas is produced.

  
  

• Energy is absorbed.

  
  

• There is an explosion.

  
  

• There is color change .

  
  

Tags

NGSS.MS-PS1-2

Which statement most accurately describes what happens when a bar of chocolate melts?

• A physical change takes place that causes molecules to move slower. 

  
  

• A physical change takes place that causes molecules to move faster.

  
  

• A chemical change takes place that causes molecules to move slower. 

  
  

• A chemical change takes place that causes molecules to move faster.

  
  

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4