Unit 4: Chemistry

A student makes some observations about three solids and summarizes the results in the table below. Sample | Mass | Melting Point | Color ---------|--------|---------------|------ Solid 1 | 10.2 g | 36°C | white Solid 2 | 3.4 g | 36°C | white Solid 3 | 3.4 g | 100°C | white Which of the solids from the table above could you claim are both made of the same type of molecule throughout?

• Only solids 1 and 2

• Only solids 2 and 3

• All of the solids

• None of the solids

Which change will produce a new substance?

• Dissolving cocoa mix in water

• Burning a piece of bread in a toaster

• Heating water until it evaporates

• Cooling water until it freezes

Which of the following is true about the principle of the conservation of mass?

• The mass of the products is never equal to the mass of the reactants.

• The mass of the products is less than the mass of the reactants.

• The mass of the products is equal to the mass of the reactants.

• The mass of the products is greater than the mass of the reactants.

Which of the following is a chemical reaction?

• New atoms are formed when substances are mixed together

• A solid material melts and becomes a liquid.

• Atoms of the reactants rearrange to form a new substance.

• A liquid evaporates and turns into gas.

You find a clear gem that is made of one substance. What could you do to identify whether the gem is a diamond?

• Measure its length and compare it to the length of other gems, including diamonds.

• Determine its shape and compare it to the shape of other gems, including diamonds.

• Determine its melting point and compare it to the melting point of other gems, including diamonds.

• Measure its mass and compare it to the mass of other gems, including diamonds.

In the picture below, ammonia and bleach are mixed together. How many nitrogen (N) atoms will be in the products?

• 1

• 2

• 3

• 6

How does the figure below show the conservation of mass? (MS-PS1-5 DOK 2)

• Solid A is shown to react with liquid B to form a new substance C.

• Solid A and liquid B are the same.

• Solid A and liquid B show only a color change.

• The mass of solid A and the mass of liquid B combine to equal the mass of mixture C.

Which substances are reactants in this chemical equation? 2H2 + O2 --> 2H2O

• 2H₂O

• H₂ and O₂

• H and O

• There are no reactants.

The Law of Conservation of Mass is a scientific rule that says:

• Mass can be made or lost during a chemical reaction

• Mass is never made or lost during a chemical reaction.

• All matter will decompose during a chemical reaction.

• Baking a cake is not actually a chemical reaction.

What property of metals is a jeweler able to use to help identify between copper and yellow-gold rings?

• Volume

• Mass

• Shape

• Density