Is Matter Around Us Pure

Which statement correctly distinguishes mixtures from compounds?

1. Mixtures have fixed composition, while compounds do not.
2. Compounds can be separated by physical methods.
3. Mixtures have variable composition, while compounds have fixed composition.
4. Mixtures are always pure substances.

Which of the following statements is true about a true solution?

1. It is heterogeneous.
2. Its particles settle on standing.
3. It has uniformly distributed particles and does not scatter light.
4. It can be separated by filtration.

Which of the following cannot be separated by physical methods?

1. Mixture of sand and salt
2. Air
3. Water
4. Iron filings and sulfur

Which method is used to obtain pure water from salt solution?

1. Filtration
2. Evaporation
3. Distillation
4. Sieving

Which separation technique is used to separate different colors present in ink?

1. Filtration
2. Distillation
3. Chromatography
4. Sedimentation

Which of the following is a colloid?

1. Sugar solution
2. Salt solution
3. Milk
4. Copper sulphate solution

Which mixture settles down on standing?

1. True solution
2. Colloid
3. Suspension
4. Compound

The Tyndall effect is shown by

1. True solutions only
2. Colloids only
3. Pure substances only
4. Compounds only

Which of the following is an example of an element?

1. Carbon dioxide
2. Water
3. Copper
4. Sugar

Which of the following is an example of a compound?

1. Oxygen
2. Iron
3. Water
4. Air

Which technique is used to separate dissolved salt from seawater?

1. Filtration
2. Sublimation
3. Evaporation
4. Magnetic separation

Which method is commonly used to separate insoluble solids from liquids?

1. Distillation
2. Filtration
3. Evaporation
4. Chromatography

A heterogeneous mixture is one in which

1. The composition is uniform throughout.
2. The components are chemically combined.
3. The composition is not uniform throughout.
4. It contains only one substance.

Which of the following is a pure substance?

1. Air
2. Salt (Sodium Chloride)
3. Milk
4. Soil