Mixtures and Solutions

A student adds10 grams of four different powdered solids into four different beakers. The student then adds 100 mL  of water to each beaker, stirs the mixtures, and allows them to sit for half an hour before recording observations. Which question is the student most likely trying to answer?

• At which water temperature do the substance dissolve?
• How much water is needed to cause a substance to change state?
• What causes a substance to sink when put in water? 
• Which substance dissolve?

A student places a sugar cube in a beaker of water.What change will occur? 

• The sugar cube will not change?
• More water will be formed.
• The sugar cube will become smaller. 
• The water will form crystals. 

Which of the following is the best evidence that sugar has dissolved in water?

• The sugar seems to disappear in the water. 
• The water temperature increases 

A company collects cans for recycling. Some cans are made of aluminum, and some are made of iron. Which of the following is the best way to separate the two types of cans? 

• Heat the iron cans until they melt. 
• Use scissors to cut the cans.
• Use a magnet to pick up the iron cans. 
• Float the cans in water.

Which tool can be used to remove iron fillings from a mixture? 

• Magnifying glass
• A funnel 
• Balance beam 
• Magnet

Which of these mixtures would be easiest to separate? 

• Fruit salad
• Powerade 
• Hot chocolate
• Instant pudding 

A student made a mixture using equal parts of salt and pepper. The salt grains were the same size as the pepper grains. What should the student do to most easily separate pepper from the salt?

• Use a pair of tweezers
• Run a small magnet through the mixture
• Put the mixture in water and filter it
• Use a stainer with a fine wire screen 

A student mixes three spoonfuls of sand with one cup of water in an open container. The students put the container of sand and water near a window for four days. How many spoonfuls of sand will be in the container when all the water has evaporated?

• 1
• 2
• 3
• 4

Carbon powder and iron fillings are both black powder. Which of these would be the best to use to separate the iron fillings from the carbon powder?

• a magnifying glass
• heat
• magnet
• water

Some people add sugar to their hot tea. Which property of the sugar remains the same when the sugar is in the tea solution?

• The taste of sugar
• The size of the sugar crystals 
• The color of the sugar
• The texture of the sugar