Other Chemistry Answers

1.Vanadium (V) oxide is used to catalyse the exothermic reaction between sulfur dioxide and oxygen in the Contact Process.

2SO2 + O2 = 2SO3

The rate of this reaction can be increased either by using a catalyst or by increasing the temperature.
Explain why a catalyst is used and not a higher temperature.

(a) What is the oxidation number of the named element in the following compounds?

(i) manganese in Mn2O7

(ii) Iron in Fe(CN)6^3

(1)Describe the trend in the reactivity of the halogens Cl2, Br2 and I2 as oxidising agents. Explain this
trend using values E ° (X^2/X-) from the Data Booklet.

(i) Write an equation for the reaction between chlorine and water

(ii) Use standard electrode potential, E^0(symbol 0 with a line across) data from the Data booklet to calculate the E^0 cell for the
following reaction.

Cl2 + 2OH- = Cl- + ClO- + H2O

E^0 cell =............................. V

1.Vanadium is a transition element. it has more than one oxidation state. The element and its compounds are often used as catalysts.

The oxidation states of vanadium in its compounds are V (+5), V (+4), V (+3) and V (+2). The vanadium (lll) ion can behave as a reductant or an oxidant.

(i) indicate on the following equation which reactant is the oxidant.

2V^3+ + Zn = 2V^2+ + Zn^2+

(ii) which change in the following equation is oxidation?
Explain your choice.

V^3+ + Fe3+ = V^4+ + Fe^2+

Vanadium is a transition element. it has more than one oxidation state. The element and its compounds are often used as catalysts.

(a) Complete the electron distribution of vanadium by inserting one number.

2+8+ .......... +2

(b) Vanadium (V) oxide is used to catalyse the exothermic reaction between sulfur dioxide and oxygen in the Contact Process.

2SO2 + O2 = 2SO3

The rate of this reaction can be increased either by using a catalyst or by increasing the temperature. Explain why a catalyst is used and not a higher temperature.

(a) What is the oxidation number of the named element in the foilowing compounds?

(i) manganese in Mn2O^7

(ii) iron in Fe(CN6)^3-

(b) Use the oxidation number method to balance the equation below.

MnO4-(aq) + H+ (aq) + Fe^2+ (aq) = +Mn^2+ (aq) + Fe^3+ (aq) + H20 (I)

Which element was oxidized and which was reduced?

Oxidized:
Reduced:

(c) in the reaction between iodine and thiosulphate ions, the two half reactions are

I2 + 2e- = 2I-

2S2O3^2- = S4O6^2- + 2e-

Use the half equation above to write a single balanced equation, Step by step.

Nitryl chloride, NO2CI, reacts with nitric oxide, NO. The forward reaction is exothermic.

NO2Cl(g) + NO(g) = NO2(g) + NOCl(g)

The reaction can reach equilibrium.

(a) What is meant by the term equilibrium for a reversible reaction?

(b) Explain why increasing the temperature increases the rate of reaction.

(c) State and explain the effect, if any, of increasing the temperature on the position of equilibrium

(d) State and explain the effect, if any, of decreasing the pressure on the position of equilibrium.

A girl with a mass of 45 kg is standing on a scale in a lift. What is the weight of the girl when (i) the lift is accelerating upwards at 2.0 ms s −2 and (ii) the lift is moving down with a constant velocity. Calculate the inertial force in each case.

A 40.0 g sample of ethanol (Csp = 2.46 J/g °C) releases 2952 J as it cools from 50.0 °C. Calculate the change in temperature of the ethanol. °C

Calculate the specific heat capacity of titanium if a 45 g sample absorbs 476 J as its temperature changes from 20⁰C to 40.25⁰C. J/g ⁰C (2 decimals)