1s Sems Review A

What is a compound?

• A mixture of elements

• A chemical combination of elements

• A single element

• A physical combination of elements

Tags

NGSS.MS-PS1-1

According to the Law of Definite Composition, how do elements in a compound combine?

• In any proportion by mass

• In a 1:2 ratio by mass

• In the same proportion by mass

• In a 2:1 ratio by mass

What is the mass ratio of hydrogen to oxygen in water?

• 1:2

• 2:1

• 1:8

• 8:1

What is the purpose of heating magnesium in the Law of Definite Composition experiment?

• To melt the magnesium

• To react it with nitrogen

• To react it with oxygen

• To dissolve it in water

Tags

NGSS.HS-PS1-5

What is the correct procedure for smelling chemicals in the lab?

• Directly inhale the vapors.

• Waft the vapors to your nose.

• Smell the container directly.

• Avoid smelling at all.

What is the purpose of making sure the magnesium ribbon is clean and shiny?

• To improve its appearance.

• To ensure it reacts properly.

• To make it easier to handle.

• To increase its weight.

With what element does magnesium combine when strongly heated? What is the source of this element?

• Nitrogen from the air.

• Oxygen from the air.

• Hydrogen from water.

• Carbon from carbon dioxide.

If you were to combine 80 grams of oxygen with some hydrogen, how much hydrogen would you need to completely use up all of the oxygen?

• 10 grams

• 5 grams

• 20 grams

• 40 grams

Tags

NGSS.HS-PS1-7

Suppose a compound of sodium and chlorine is formed in the mass ratio of 1.54 grams of chlorine, Cl, for each gram of sodium, Na. How much sodium would you need to completely react all 45.0 grams of chlorine?

• 29.2 grams

• 45.0 grams

• 30.0 grams

• 35.0 grams

Tags

NGSS.HS-PS1-7

What is the accepted mass ratio for the mass of magnesium to the mass of oxygen?

• 1.52

• 1.25

• 2.15

• 1.35

Tags

NGSS.HS-PS1-7