To decide if a chemical reaction has happened, you should measure and compare which of the following?

• volume of the materials
• shape of the products
• properties of the substances
• mass of the reactants

A student found 2 green powders that look the same.  He wants to figure out if they are the same substance.  Which of the following is the best method?

• Measure teh mass, volume, and temperature of each powder
• Combine both powders to find out if there is a chemical reaction
• Mixt the two properties together and then test the properties
• Determine the density, solubility, melting point of each powder and compare

What does this model represent?

• a phase change
• a substance
• a chemical reaction
• a mixture

A piece of copper is a substance because it..

• is made of the same type of atom throughout
• consists of many different types of atoms
• can be made into something different
• reacts with other substances

A property is ...

• determined by the amount of substance
•  made of one type of substance
• a process to make a new substance
• a characteristic of a substance

If you have two substances A and B and they are both solids.  Would you expect their melting points to be the same or different?

• the same because they are both solid at room temperature
• the same because they are made of teh same types of atoms
• different because they have different mass
• different because they are made of different molecules

You have a solid yellow powder that dissolves in water when stirred into 100 mL of water.  Predict what will happen when you stir it into 200mL of water.

• it will settle to the bottom and not dissolve
• it will float and then settle to the bottom and not dissolve
• it will float and not dissolve
• it will not settle but dissolve

Which of the following is an example of a chemical reaction?

• mixing lemonade powder with water
• burning marshmallows over a fire
• melting butter in a pan
• boiling water on a stove

A chemical reaction occurs when substances interact and their atoms ...

• disappear
• change their size
• become new atoms
• rearrange in a new way

I know that solubility is a property because....

• It is true in water or oil
• It is only true when I have enough of a substance
• It is true of that substance if there is a little or a lot.
• It is true of more then one substance all the time.