Mixtures

A fifth grade class has collected empty cans for recycling. They have several large bins with aluminum and steel cans, all mixed together. The two types of cans must be separated. Which of the following techniques could the students use to separate the two types of cans?

• Place the cans in water, and the aluminum cans will float
• Crush the cans to make them easier to carry
• Test the cans for their ability to conduct electricity
• Use a magnet to find and remove the steel cans

What property of tea changes when it is mixed with sugar?

• color
• taste
• shape
• state

Students collected data on the appearance of four substances and how they reacted when mixed with water. Which substances dissolved when mixed with water?

• A and B
• A and C 
• B and C 
• C and D

Students were asked to follow the laboratory procedure below:  
1. Measure out 10 grams of salt  
2. Dissolve the salt in 150 ml of pure water 3. Evaporate the water  
4. Measure the mass of the remaining salt Which of the following would you predict for the measurement of the mass of the remaining salt in step 4?

• 0 grams
• 5 grams
• 10 grams
• 15 grams

A glass beaker contains 100 milliliters of water into which 5 grams of salt was stirred.  Which item should be used to separate this particular mixture?

• triple beam balance
• hot plate
• paper filter
• magnet

Students collected data on four substances. If the same students were then given a mystery substance made of tan crystals that dissolves in water, it could be –

• corn starch
• brown sugar
• white sugar
• sand 

What change happens when water mixes with sugar?

• The appearance of the sugar changes 
• the shape of the water changes 
• the taste of sugar changes
• the state of water changes 

A student collects seashells at the beach. The student ends up with a bucket containing seashells, but also sand and water. Which of the following tools will be most helpful for separating the seashells from the sand and water?

• sieve
• magnet
• hand lens
• balance 

Students were asked to separate a mixture of sand and salt. One group decides to first put the mixture into a beaker of water. What next steps will allow them to separate out the sand and salt?

• Pour the mixture through the filter to remove the sand and then evaporate the water
• use a magnet to extract the sand 
• use a colander to catch the the sand and then a filter to catch the salt
• Boil the mixture.  Scrape the salt off the ceiling that evaporated

Sugar is added to water and stirred until it completely dissolves. Which of the following correctly describes something that has happened to the sugar?

• the mass of the sugar increased
• the mass of the sugar decreased
• the sugar disappeared and no longer exists
• the sugar is evenly distributed in the water