4th form Chemistry

Which of the following properties would most likely not belong to a simple covalent solid?

• Low melting point

• Soluble in nonpolar solvents

• High melting point

• Conducts electricity

Diamond and graphite are allotropes of carbon. Sulphur also has allotropes. Which of the following would not be a property of alltropes?

• Made up of different elements

• Same chemical properties

• Possesses similar chemical bonds

• Different physical properties

What are the values of a, b, c and d respectively for the balanced equation aPb(NO₃)₂ + bNa₂SO₄ --> cNaNO₃ + dPbSO₄

• 1,1,1,1

• 1,2,2,1

• 1,1,2,1

• 2,2,2,2

Diffusion occurs from

• a region of high concentration to a region of low concentration

• a region of low concentration to a region of high concentration

• a region of high concentration to a region of low concentration across a semi-permeable membrane

• a region of low concentration to a region of high concentration across a semi-permeable membrane

20 g of ammonia would contain....... molecules of ammonia. Note A_r N = 14, H = 1 and Avogadro's constant 6 x10²³

• 1.2

• 0.9

• 5.4 x 10²³

• 7.2 x 10²³

Particle ₈¹⁷X has a charge of 2-. Which of the following would be correct about particle X?

• It has 8 electrons

• It has 17 neutrons

• It has 10 electrons

• It has 9 protons

Above is a heating curve for substance HC4. What state(s) of matter would present at point II on the curve?

• solid and liquid

• solid only

• liquid and gas

• liquid only

Above is a heating curve for substance HC4. What is the boiling point of HC4?

• 110 ^oC

• 100 ^oC

• 0 ^oC

• -30 ^oC

Which of the following would most likely represent the empirical formula of a compound?

• AlO_1.5

• N₂H₄

• C₂H₄O₂

• CH₄

From the symbol ₂⁴He, it can be deduced that

• an atom of helium has a charge of 2+

• an atom of helium has 2 electrons

• an atom of helium has 2 protons and 4 neutrons

• helium occurs as a diatomic molecule