IQWST

A student created a model to show what happens before and after a process. Does this model represent a chemical reaction. Choose all the answers that will create a CER.

• This model shows a chemical reaction because all of the atoms are rearranged to form something new.

• The model shows that 2 Mg plus 2 O formed a new substance could 2MgO.

• Since, the product is different then the reactant, I know a chemical reaction occurred.

• I know this is correct by looking at the model.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Jay had two clear liquids in bottles. The mass of one liquid was 10.0 grams and the other was 7.0 grams. When he mixed them, a yellow solid formed and settled to the bottom of the bottle. He predicted that the liquid plus the solid would have more mass, so he put the bottle on a scale. The mass was 17.0 grams. Why did the mass not change?

• Because it is a mixture and mass doesn't change.

• His scale is broken.

• Do to the Law of conservation of mass, matter cannot be created nor destroyed so the mass is the same as the reactant and the product.

• He forgot to tare his bottle and the scale had the mass of the bottle added in.

Tags

NGSS.MS-PS1-5

Which statement is always true about conservation of matter?

• If a gas forms, the mass of a system decreases.

• The mass of a system does not change during a chemical reaction.

• If a solid forms, the mass of a system increases.

• The mass of a system changes when a substance changes from liquid to gas, but it does not change in a chemical reaction.

Tags

NGSS.MS-PS1-5

Describe three pieces of evidence you could look for to determine whether a chemical reaction occurred.

• Formation of a gas

• Formation of a precipitate

• Temperature change

• Color change

• property change

Tags

NGSS.MS-PS1-2

List the steps of the scientific method

d

e

f

c

b

a

Conduct experiment

Communicate results

Analyze results

Ask a question

Draw conclusions

Form a hypothesis

Tags

NGSS.MS-PS2-2

According to the model, how does the total mass compare to the total mass after two weeks? Write an explanation to support your answer.

• The mass will stay the same because matter is neither created or destroyed the atoms are just rearranged to form something new.

• The mass will change because it is in an open system.

• The mass will decrease because after time the oxygen will float away.

• The mass will stay the same because it is the same thing.

Tags

NGSS.MS-PS1-5

Seth learned in school that iron reacts with oxygen in the air to form iron oxide. The chemical equation is: Fe + O2 🡪 FeO2 Seth wanted to see if this would really happen, so he put 13 grams of tiny iron (Fe) pieces on the window sill outside his house. After two weeks, he saw that the iron no longer looked shiny. He checked the mass of the pieces and saw that it went from 13 to 21 grams. Seth’s friend said this shows that matter is not conserved. Do you agree or disagree with Seth’s friend? Select all the answers to make a CER.

• Seth's friend is wrong because matter is conserved and the iron went up because it is now a new substance.

• The Iron combined with oxygen and added 8 grams of oxygen in the chemical reaction causing the mass to go up.

• This chemical reaction occurred in an open system which is why the mass went up.

• Since, I know matter cannot be created or destroyed I can say that Seth's friend is wrong and that matter is conserved in this chemical reaction.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A scientist has two containers. Inside each container is a blue liquid. The liquids are substances. What can the scientist do to help find out whether these two liquids are both the same substance?

• Measure the density of the two liquids and compare the densities.

• Weigh each liquid and compare the weights.

• Measure the volume of each liquid and compare the volumes.

• Measure the temperature of each liquid and compare the temperatures.

Tags

NGSS.MS-PS1-2

Which is the least dense material?

• grape

• syrup

• oil

• cork

Soda contains a large amount of sugar. Why can't it be seen in the liquid?

(Scientific Principle #4)

• The sugar has a chemical reaction with the soda.

• The sugar dissolves in the soda.

• The sugar is taken out of the soda.

• The sugar was invisible before it was added to the soda.

Tags

NGSS.MS-PS1-2