Mixtures and Solutions

A student stirred 10 grams of salt into 50 mL of water and 10 grams of sand into 50 mL of water and let both mixtures sit for ten minutes.
What important difference is observed between these two mixtures?

• The salt, sand, and water do not mix together.
• Salt dissolves in the water but sand does not.
• Mixture 2 can be separated, but Mixture 1 cannot.
• Mixture 1 is a solid and a liquid, but Mixture 2 is not.

A magnet would be most useful in separating which of the following mixtures?

• salt and water
• rocks and soil
• sugar and iced tea
• iron fillings and sand

A student investigated what happens when different substances are added to water. The table shows his results.
In which mixture does one substance dissolve in another?

• pepper and water
• sand and water
• sugar and water
• flour and water

The table shows different sizes of particles found in a sample of sand. Students have a strainer with holes that are 500 micrometers wide. The strainer could be used to separate which of the following mixtures?

• Very fine sand and find sand
• Fine sand and medium sand
• Medium sand and coarse sand
• Coarse sand and very coarse sand

What does a mixture of rocks and water have in common with a mixture of salt and water? In both mixtures - 

• two substances are combined
• a solid dissolves in a liquid
• the same substances are used
• the final appearance is the same

A sieve is a wide container with a flat bottom. The bottom has many small holes, all the same size. Which of the following mixtures could be separated using a sieve?

• nuts and raisins
• salt and pepper
• sand and gravel
• aluminum nails and iron nails

Which of the following mixtures could be separated by using only evaporation?

• oil and water
• sand and gravel
• water and sugar
• sugar and salt

A student filled two containers with 50 mL of water and added 10 mg of sand to the first one and 10 mg of salt to the second.
What is the difference between these two mixtures?

• Only Mixture 1 begins with a liquid and a solid.
• Only Mixture 2 can be separated with a magnet.
• In Mixture 1 only, the solid will float on the water.
• In Mixture 2 only, the properties of the solid change.

Which of the four mixtures could be separated using the following procedures?
Step 1: Place the mixture in a basin of water and scoop out what floats on the water.
Step 2: Dry off the remaining mixture and use a magnet to separate the last two components.

• mixture 1
• mixture 2
• mixture 3
• mixture 4

Mixture 1 is different from Mixture 2 because only in Mixture 1 - 

• is there any liquid
• will there remain a solid
• was there any dissolving
• did ingredients stay the same