Separating Mixtures

Ahmed, Tanya and Mariam wanted to find out if some food colourings contained a banned food dye. They put a drop of each food colouring and the banned food dye onto some special paper. They hung the paper in a beaker of water. After 10 minutes, the banned food dye and some of the dyes from the food colourings had moved up the paper. What is this separation technique called?

• Evaporation

• Filtration

• Chromatography

• Distillation

Ahmed, Tanya and Mariam wanted to find out if some food colourings contained a banned food dye. They put a drop of each food colouring and the banned food dye onto some special paper. They wrote the labels on the paper in pencil and then hung the paper in a beaker of water. After 10 minutes, the banned food dye and some of the dyes from the food colourings had moved up the paper as shown in the chromatogram. Why should they write the labels in pencil and not in ink?

• Because ink is insoluble in water and will affect the results.

• Because pencil lead is soluble in water and will affect the results.

• Because ink and pencil lead are insoluble in water and will not affect the results.

• Because ink is soluble and pencil lead is insoluble in water and will not affect the results.

Tags

NGSS.MS-PS1-2

Ahmed, Tanya and Mariam wanted to find out if some food colourings contained a banned food dye. Look at their results. The different dyes in some of the food colourings had moved up the paper. Which food colouring contained the banned food dye?

• red

• blue

• green

• brown

• yellow

Tags

NGSS.MS-PS1-2

Ahmed, Tanya and Mariam wanted to find out if some food colourings contained a banned food dye. Look at their results. The different dyes in some of the food colourings had moved up the paper as shown in the chromatogram. Which food colouring contained the most dyes?

• red

• blue

• green

• brown

• yellow

Tags

NGSS.MS-PS1-2

Ahmed, Tanya and Mariam wanted to find out if some food colourings contained a banned food dye. Look at their results. The different dyes in some of the food colourings had moved up the paper as shown in the chromatogram. Which food colouring did not dissolve in the water?

• red

• blue

• green

• brown

• yellow

Tags

NGSS.MS-PS1-2

Gary used water as the solvent to separate a mixture of dyes using a special paper but it did not work. He then used ethanol instead of water and it worked. Suggest why the experiment worked with ethanol but not with water.

• The dyes were soluble in water but insoluble in ethanol.

• The dyes were insoluble in water but soluble in ethanol.

• The dyes were insoluble in both water and ethanol.

• The dyes were soluble in both water and ethanol.

Neera and Tom dissolved different masses of salt in 500 cm³ of water. They measured the temperature at which each salt solution boiled. They wrote down the variables that might affect the investigation. What is the independent variable (the variable they changed) in their investigation?

• temperature of the laboratory

• mass of salt dissolved in water

• starting temperature of the water

• boiling point of salt solution

• volume of water

Tags

NGSS.MS-PS1-2

Neera and Tom dissolved different masses of salt in 500 cm³ of water. They measured the temperature at which each salt solution boiled. They wrote down the variables that might affect the investigation. What is the dependent variable (the variable they measured) in their investigation?

• temperature of the laboratory

• mass of salt dissolved in water

• starting temperature of the water

• boiling point of salt solution

• volume of water

Tags

NGSS.MS-PS1-2

Neera and Tom dissolved different masses of salt in 500 cm³ of water. They measured the temperature at which each salt solution boiled. They wrote down the variables that might affect the investigation. Which variable should they control (keep the same) to make sure it is a fair test?

• temperature of the laboratory

• mass of salt dissolved in water

• boiling point of salt solution

• volume of water

• type of salt used

Tags

NGSS.MS-PS1-2

Neera and Tom dissolved different masses of salt in 500 cm³ of water. They measured the temperature at which each salt solution boiled. What safety measures should they follow?

• Tie long hair back.

• Wear safety goggles.

• Do not touch hot appratus. Let them cool down.

• All of the options.