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Chemistry
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
I2 + 2e- = 2I-
2S2O3^2- = S4O6^2- + 2e-
Use the half equation above to write a single balanced equation
Chemistry
Which change in the following equation is oxidation?
Explain your choice
V^3+ + Fe^3+ = V^4+ + Fe^2+
Explain your choice
V^3+ + Fe^3+ = V^4+ + Fe^2+
Chemistry
(a) Oxygen was formed at the anode and copper was formed at the cathode.
(i) The ionic half-equation for the formation of oxygen is shown.
4OH- = O2 + 2H2O + 4e-
Explain why this reaction is oxidation.
(i) The ionic half-equation for the formation of oxygen is shown.
4OH- = O2 + 2H2O + 4e-
Explain why this reaction is oxidation.
Chemistry
A. Use the Oxidation number method to balance the equation below.
MnO4-(aq) + H+ (aq) + Fe^2+ (aq) = Mn^2+ (aq) + Fe^3+ (aq) + H2O (l)
B. Which element was oxidized and which was reduced?
Oxidized:
Reduced:
MnO4-(aq) + H+ (aq) + Fe^2+ (aq) = Mn^2+ (aq) + Fe^3+ (aq) + H2O (l)
B. Which element was oxidized and which was reduced?
Oxidized:
Reduced:
Chemistry
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+
(i) indicate on the following equation which reactant is the oxidant.
2V^3+ + Zn = 2V^2+ + Zn^2+
Chemistry
1.Oxygen was formed at the anode and copper was formed at the cathode.
(i) The ionic half-equation for the formation of oxygen is shown.
40H- = O2 + 2H2O + 4e-
Explain why this reaction is oxidation.
(ii) Write the ionic half-equation for the formation of copper at the cathode.
(2) The electrolysis was repeated using copper electrodes in place of carbon electrodes.
State and explain what happens to the masses of the anode and the cathode during this electrolysis.
(i) The ionic half-equation for the formation of oxygen is shown.
40H- = O2 + 2H2O + 4e-
Explain why this reaction is oxidation.
(ii) Write the ionic half-equation for the formation of copper at the cathode.
(2) The electrolysis was repeated using copper electrodes in place of carbon electrodes.
State and explain what happens to the masses of the anode and the cathode during this electrolysis.
Chemistry
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.
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.
Chemistry
(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
(i) manganese in Mn2O7
(ii) Iron in Fe(CN)6^3
Chemistry
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.
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.
Chemistry
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.
