Conservation of Mass Review

A student melts an ice cube in a sealed plastic container. After the ice has completely melted, what will the weight of the container and its contents be?

• Less than before because the ice melted

• More than before because water is heavier than ice

• The same as before because no matter was added or removed

• Zero, because the ice has disappeared

Tags

NGSS.MS-PS1-4

NGSS.MS-PS1-5

A class combines vinegar and baking soda in a sealed bag. After the reaction, the bag feels full of gas. What is the best way to find out if the weight has changed?

• Smell the gas

• Weigh the bag before and after the reaction

• Feel how heavy the bag is with your hands

• Open the bag and check inside

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Why is it important to use a sealed container when comparing the weight of substances before and after a reaction?

• So you can see the reaction better

• To trap all the heat

• To make sure no matter escapes

• So it doesn't make a mess

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Two balls are weighed before and after they are used in a game of catch. What should students expect about the weight?

• The balls will weigh less because they were moving

• The balls will weigh more because of the air around them

• The balls will weigh the same unless something was added or lost

• The balls will weigh more because of the energy they used

A student wants to test whether mixing two powders changes the weight. What should they do first?

• Mix the powders and see what happens

• Weigh each powder and then weigh the mixture

• Ask the teacher what the weight should be

• Taste the powders to guess the weight

Tags

NGSS.MS-PS1-5

If you tear a sheet of paper into small pieces and collect them all, what should happen to the total weight?

• It will increase

• It will decrease

• It will stay the same

• It will become zero

Tags

NGSS.MS-PS1-5

A student mixes salt into a cup of water. The salt dissolves. What will happen to the weight of the cup and its contents?

• It will weigh more than before

• It will weigh less than before

• It will weigh the same as the water alone

• It will weigh the same as the water and salt combined

Tags

NGSS.MS-PS1-5

Which tool is best for measuring the weight of an object before and after a change?

• Ruler

• Thermometer

• Balance scale

• Stopwatch

Tags

NGSS.MS-PS1-5

You crumple a piece of aluminum foil into a ball. What happens to its weight?

• It increases

• It decreases

• It stays the same

• It becomes zero

A group of students places two substances in a closed container and shakes it to mix them. What should they do to compare the weight before and after?

• Open the container to check

• Weigh the container before and after

• Count the number of particles inside

• Guess based on what they see

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5