(09/06) Flashback -Chemical Change/Aqueous Solutions

Which of the following most likely describes the reaction in the diagram?

• The heat created a chemical reaction between iron and sulfur, creating a COMPOUND of iron sulfide with new chemical properties.

• The heat created a physical change between iron and sulfur, creating a MIXTURE with new physical properties.

• The heat evaporated the iron and sulfur creating a PRECIPITATE with new chemical properties.

• The heat melted the iron and sulfur, creating a SOLUTION with new physical properties.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

12 g of NaCl (salt) are dissolved into a beaker containing 50 mL of water at room temperature. How could the saltwater solution be diluted?

• A solution cannot be diluted

• To dilute the solution, add more water

• To dilute the solution, add more salt and water in the original proportion.

• To dilute the solution, add more salt

The ____________ the surface area, the faster the rate of dissolution, or dissolving.

What is the primary difference between a compound and a mixture?

• A compound is a chemical combination of elements, while a mixture is a physical combination of substances.

• A compound can be separated by physical means, while a mixture cannot.

• A compound has variable composition, while a mixture has a fixed composition.

• A compound is always a solid, while a mixture can be solid, liquid, or gas.

Mixing milk and vinegar created a precipitate, which is an indication of a chemical change. What are other indicators of a chemical change?

Select all answers that apply.

• Red Kool Aid mixed in water creates color change

• Bubbles/Fizzing

• carving wood into a sculpture

• New substance is created

• Temperature decreases

Tags

NGSS.MS-PS1-2

What is an example of a physical change during digestion of food in your body?

• Acids reacting to the candy and change it into another substance.

• Acids in the saliva change the size of the candy

• Stomach acids break down the candy

• Chewing the candy and breaking it down with your teeth.

When sugar is dissolved in water, what type of change occurs?

• Chemical change

• Physical change

• Both chemical and physical change

• No change

The smaller the surface area, the ___________ the rate of dissolution, or dissolving.

How does adding more water (solvent) affect the solution?

• concentration increases

• dilution increases

• concentration decreases

• dilution decreases

Tags

NGSS.MS-PS1-2

How does increasing the amount of solute affect a solution?

• Increases the concentration

• decreases the concentration

Tags

NGSS.MS-PS1-2