Which of the following is not an exothermic reaction?

Antara yang berikut, yang manakah bukan tindak balas eksotermik?

1. The energy profile diagram represents an endothermic reaction.

Gambarajah profil tenaga mewakili satu tindak balas endotermik.

Which of the following A, B, C and D, represents the heat change?

Antara A, B, C dan D yang manakah menunjukkan perubahan tenaga?

When concentrated sulphuric acid dissolves in a beaker of water, the beaker gets hot. This is due to

Apabila asid sulfurik pekat dilarutkan dalam satu bikar air, bikar menjadi panas. Hal ini adalah disebabkan oleh

The chemicals in cold packs react to absorb heat. Which of the following substances is used in cold packs?

Bahan kimia dalam pek sejuk bertindak balas untuk menyerap haba. Antara bahan yang berikut, yang manakah digunakan dalam pek sejuk?

The reaction between hydrochloric acid and sodium hydroxide is an exothermic reaction. The heat of reaction is -57 kJ mol ⁻¹ .

Which of the following energy level diagrams represents the reaction?

Tindak balas antara asid hidroklorik dengan natrium hidroksida adalah tindak balas

eksotermik. Haba tindak balas adalah -57 kJ mol ⁻¹ .

Antara gambar rajah aras tenaga berikut yang manakah mewakili tindak balas itu?

The thermochemical equation represents the reaction between aluminium and copper(II) sulphate solution.

Persamaan termokimia mewakili tindak balas antara aluminium dan larutan kuprum(II) sulfat.

2Al + 3CuSO₄ → Al₂(SO₄)₃ + 3Cu ΔH = - 42 kJ mol^-1

What is the temperature change when excess aluminium powder is added to 50 cm³ of 0.5 mol dm^-3 copper(II) sulphate solution in a polystyrene cup?

[Specific heat capacity of water = 4.2 Jg^-1 C^-1 ; Density of water = 1.0 g cm^-3]

Berapakah perubahan suhu apabila serbuk aluminium berlebihan ditambah kepada 50 cm³ larutan kuprum(II) sulfat 0.5 mol dm^-3?

[Muatan haba tentu air = 4.2 Jg^-1 C^-1 ; Ketumpatan air = 1.0 g cm^-3]

The following equation represents the reaction between hydrogen and chlorine.

Persamaan berikut mewakili tindak balas antara hidrogen dan klorin.

H2 (g) + Cl2 (g) → 2HCl (g)

Table shows the energy content for some chemical bonds.

Jadual menunjukkan kandungan tenaga bagi beberapa ikatan kimia.

What is the heat of the reaction?

Berapakah haba tindak balas?

Formula = heat energy of reactants - heat energy of products

In an experiment , 2 g of magnesium powder is added to 50 cm³ of 0.2 mol dm^-3 zinc sulphate solution. Th temperature of the mixture increases by 12 °C. What is the heat of displacement in the experiment?

[Specific heat capacity of a solution = 4.2 J g ^{– 1} °C ^{– 1} ; Relative atomic mass of Mg = 24]

Dalam satu eksperimen, 2 g serbuk magnesium ditambahkan kepada 50 cm³ larutan zink sulfat 0.2 mol dm ^{– 3}. Suhu campuran meningkat sebanyak 12 °C. Berapakah haba penyesaran dalam eksperimen ini?

[Muatan haba tentu larutan = 4.2 J g ^{– 1} °C ^{– 1}, Jisim atom relatif Mg = 24]

Which are the following pairs of acid and alkali will produce the lowest temperature change when mixed together? (All the acids and alkalies have the same concerntration of 1.0 mol dm^-3)

What is the meaning of heat of neutralization?

The table shows the heat of combustion of three alcohols.

Which of the following factors increases the heat of combustion of alcohols?

The following equation shows the combustion of heptane, C₇H₁₆, in excess oxgen.

C₇H₁₆(l) + 11 O₂(g) → 7 CO₂(g) + 8 H₂O ΔH= -5 512 kJ mol^-

The combustion of heptane in excess oxygen releases 1 378 kJ of energy.

What is the mass of heptane used?

[relative atomic mass of H = 1 and C = 12]

The following information shows the results of an experiment to determine the heat change for the combustion of propanol, C₃H₇OH.

Volume of water in the copper container= 300 cm³

Initial temperature of water in copper container=27.5 °C

Highest temperature of water in copper container = 68.5 °C

What is the heat released by the combustion of propanol, C₃H₇OH?

[Specific heat capacity of water = 4.2 J g^-1°C^-1 ; Water density = 1 g cm^-3]

Convert 42 kJ into joules

The following equation shows the reaction between  $Ag^+$  and  $Cl^-$  ions.
 $Ag^+$  +  $Cl^-$  -> AgCl    $\Delta$ H= -65 $kJmol^{-1}$  
Which of the following is true about the above equation?

The diagram shows the energy profile for the formation of T from R and S.

What is the activation energy for the reaction?

In an experiment 2.4 g of magnesium powder is added to 100 cm³ of 2.0 mol dm^-3 copper(II) sulphate solution. The temperature of the mixture increases by 1.0 °C. What is the heat of reaction in the experiment?

[Specific heat capacity of a solution = 4.2 J g^{-1 0}C^-1; Relative atomic mass of Mg=24]

Which of the following acids, when added to 50 cm³ of 0.01 mol dm^-3 sodium hydroxide solution, produce the same rise in temperature of the mixture? ( more than one answer)

When 50 cm³ of 1.0 moldm^-3 nitric acid is mixed with 50 cm³ of 1.0 moldm^-3 sodium hydroxide solution the temperature increases by 6.0 °C. What is the temperature change if the experiment is repeated using 50 cm³ of 2.0 mol dm^-3 nitric acid with 50 cm³ of 1.0 mol dm^-3 sodium hydroxide?

When 100 cm³ of 1.0 mol dm^-3 of sodium hydroxide is added to 100 cm³ of 1.0 mol dm^-3 of hydrochloric acid, temperature rises by 7 °C. Which of the following mixtures will produce an increment of 14 °C in temperature?

When 100 cm³ of 1.0 mol dm^-3 hydrochloric acid reacts with 100 cm³ of 1.0 mol dm^-3 potassium hydrogen carbonate solution the temperature decreased by y °C . What is the decrease in temperature for the reaction when 50 cm³ of 1.0 mol dm^-3 hydrochloric acid reacts with 50 cm³ of 1.0 mol dm^-3 potassium hydrogen carbonate solution ?

Diagram 15 shows the set-up of apparatus to determine heat of combustion of ethanol.

The heat of combustion of ethanol was found less than the theoretical value. What can be done to improve the experimental value? ( can have more than one answer)