Atoms, Elements and Mixtures, Separating methods

Which diagram represents a chemical change?

• A

• B

• C

• D

Substance X and four known substances, P, Q, R and S, are analysed by chromatography. The chromatogram produced is shown.

Which statement about X is correct?

• It is a mixture of P, Q and S.

• It contains P and S only.

• It contains P, S and another unknown substance.

• It is a mixture of Q, R and S.

Which statement about gases is correct?

• Gases are difficult to compress when pressure is applied.

• The particles in gases are close together.

• The particles in gases have a random arrangement.

• The particles in gases move slowly past each other

Which statement is correct?

• Air is a mixture of gaseous elements only.

• Alloys are formed when a metal reacts with other elements.

• Carbon dioxide is a mixture of carbon and oxygen.

• Hydrogen (H₂) is a molecular element

Which row identifies methods of testing the purity of a compound?

• A

• B

• C

• D

Which statements describe changes that occur from left to right across a period of the Periodic Table?

1) The atomic number of the elements increases.

2) The metallic character of the elements decreases.

3) The physical state of the elements changes from gas to solid.

• 2 only

• 1 and 2

• 1 and 3

• 2 and 3

Part of the Periodic Table is shown.

Which elements are non-metal?

choose 2 answers

• A

• B

• C

• D

Sea water contains dissolved sodium chloride.

Which method is used to obtain pure water from sea water?

• chromatography

• distillation

• evaporation

• filtration

Which two processes are required to change ice into steam?

• boiling and melting

• boiling and freezing

• condensing and melting

• condensing and freezing

Four substances in a mixture are listed.

• calcium nitrate / Ca(NO₃)₂

• iron(II) sulfate / FeSO₄

• oxygen / O₂

• water / H₂O

Which statement describes the mixture?

• It contains 6 elements.

• It contains 3 compounds and 1 element.

• It contains 2 compounds and 2 elements.

• It contains 4 compounds.