Define Endothermic by picking the correct statements

Define the term Exothermic by picking the correct statements

Match the definition to the correct term.

The enthalpy change that accompanies a reaction in the molar quantities shown in a chemical reaction under standard conditions with all reactants and products in their standard states.

Match the definition below to the correct term.

The enthalpy change that takes place when one mole of a substance is formed from its elements under standard conditions, with all species in their standard states.

The enthalpy change when one mole of covalent bonds in a gaseous molecule is broken under standard conditions

Which change of state is exothermic? 

Which of the following enthalpy changes represent the enthalpy change of formation?

Which of the following equations represents the enthalpy change of combustion?

Which of the following represent the enthalpy change of atomisation?

Using the equations below:

C(s) + O2(g) → CO2(g) ∆H = –390 kJ

Mn(s) + O2(g) → MnO2(s) ∆H = –520 kJ

What is ∆H (in kJ) for the following reaction?

MnO2(s) + C(s) → Mn(s) + CO2(g)

The enthalpy change for the reaction

C(s, graphite) + 1⁄2O₂(g) --> CO(g) cannot be measured directly since some carbon dioxide is always formed in the reaction.

It can be calculated using Hess’s Law and the enthalpy changes of combustion of graphite and of carbon monoxide.

C(s, graphite) + O₂(g) --> CO₂ ΔH=-394 kJmol^–1

CO(g) + 1⁄2O₂(g) --> CO₂ ΔH=-283 kJmol^–1

The enthalpy change for the reaction of graphite with oxygen to give carbon monoxide is

Which statement is correct for this reaction?

Fe₂O₃ (s) + 3CO (g) → 2Fe (s) + 3CO₂ (g)       ΔH = −26.6 kJ

The standard enthalpy of combustion of 2-methylbut-1-ene, C₅H₁₀ is -3114 kJ mol^-1. Which of the following compounds is expected to have the same enthalpy of combustion?

The enthalpy change for the reaction, ∆H_r , is equal to

The enthalpies of combustion of C(s), H₂(g) and C4H9OH(l) (in kJmol^-1) are as follows

C(s) + O₂(g) -> CO₂(g) ∆H=a

H₂(g) + ½O₂(g) -> H₂O(l) ∆H=b

C₄H₉OH(l) + 6O₂(g) -> 4CO₂(g) + 5H₂O(l) ∆H=c

What is the enthalpy change for the reaction shown below?

4C(g) + 5H₂(l) + ½O₂(g) -> C₄H₉OH(l)

Using the data below, which is the correct value for the standard enthalpy of formation for TiCl₄(l)?

The standard enthalpy changes of combustion of carbon, hydrogen and methane are shown in the table.

Which one of the following expressions gives the correct value for the standard enthalpy change of formation of methane in kJ mol^–1?

C(s) + 2H₂(g) → CH₄(g)

The table shows the standard enthalpy of formation, Δ_fH^θ, for some of the substances in the reaction

C₂H₆(g) + 6F₂(g) ⟶ C₂F₆(g) + 6HF(g) ΔH^θ = −2898 kJ mol⁻¹

What is the standard enthalpy of formation, in kJ mol⁻¹, for HF(g)?

Using the information given, answer this question.

Fe₂O₃(s) + 3H₂(g) → 2Fe(s) + 3H₂O(g)

ΔH^⦵= +96 kJ mol⁻¹, ΔS^⦵ = +138 J K⁻¹ mol⁻¹

The standard enthalpy of formation of steam is

Use the information in the image to answer this question.

The standard enthalpy of combustion of butane, in kJ mol⁻¹, is

Use the information in the image to answer this question.

The value in kJ mol⁻¹ of the enthalpy of thermal dissociation when butane forms propane, hydrogen and carbon is

When ethanamide (CH₃CONH₂) burns in oxygen the carbon is converted into carbon dioxide, the hydrogen is converted into water and the nitrogen forms nitrogen gas.

Using the data above, which one of the following is a correct value for the enthalpy of combustion of ethanamide?

Given the data in the image

which one of the following is the enthalpy change, in kJ mol⁻¹, of the reaction below?

CH₄(g) → C(s) + 4H(g)

When 0.10 g of propane was burned the quantity of heat evolved was 5.0 kJ. The enthalpy of combustion of propane in kJ mol⁻¹ is

Hydrogen gas burns in air to form water.

2H₂ (g) + O₂ (g) → 2H₂O(I) ΔH= - 572 kJ

How much heat energy (in kJ) is given off if a rocket carrying 200.0 kg of hydrogen gas is burnt in excess oxygen?

The gaseous oxides of nitrogen such as NO, N₂O, NO₂ and N₂O₄ have positive enthalpies of formation because

When an unknown mass of ethanol was burnt, the temperature of 1 dm³ water contained in a copper beaker increased by 7.2 °C. If the enthalpy of combustion

of ethanol is -1350 kJ mol-1, determine the mass of ethanol burnt. [Specific heat capacity of solution = 4.20 J g^-1 °C^-1; density of solution = 1.0 g cm^-3; M_r of ethanol = 46]

The following table shows the change in the enthalpy of combustion (kJ mol^-1) of a hydrocarbons.

C₂H₆ = -1560 ; C₄H₁₀ = -2880 ; C₇H₁₆ = -4848

The complete combustion of 0.05 mol of a hydrocarbon W releases 176.5 kJ. What could be the molecular formula of W if W is also an alkane?

In Thermite Reaction, a reactive metal such as aluminium is used to reduce iron(lll) oxide to iron. What is the enthalpy change when 2.0 moles iron(lll) oxide is reduced by 3.0 moles aluminium? [ΔH_f (Al₂O₃) = -1676 kJ mol^-1 ; ΔH_f (Fe₂O₃) = -825 kJ mol^-1]

The standard enthalpies of combustion of graphite and hydrogen are -394 kJ mol^-1 and -286 kJ mol^-1 respectively. If the standard enthalpy of formation of ethane is -20.0 kJ mol^-1, what is the standard enthalpy of combustion of ethane in kJ mol^-1?

The standard heats of combustion per mole of butane, C₄H₁₀(g), hydrogen, H₂(g), and 1,3-butadiene, C₄H₆(g) are -2878 kJ, -286 kJ and -2540 kJ respectively. What is the heat of hydrogenation of 1,3-butadiene?

C₄H₆(g) + 2H₂(g) → C₄H₁₀(g)

When heated strongly, potassium chlorate(V) decomposes to form potassium chloride and oxygen.

2KCIO₃(s) →- 2KCI(s) + 3O₂(g)

If the heat of formation of KCIO₃ and KCI are -391.2 kJ mol^-1 and -436.7 kJ mol^-1 respectively, what is the enthalpy change when 20 g KCIO₃ is heated?

[Relative atomic mass: O = 16; Cl = 35.5; K = 39]

When 28.0 g of nitrogen reacts with oxygen to form nitric oxide, NO, and nitrogen dioxide, NO₂, 103.0 kJ of heat was required. If no nitrogen remained, calculate the mass of nitric oxide, NO formed.

[ΔH_f (NO) = 90.3 kJ mol^-1, ΔH_f (NO₂) = 33.2 kJ mo^-1]

Which is correct when Ba(OH)₂ reacts with NH₄Cl?

Ba(OH)₂ (s) + 2NH₄Cl (s) → BaCl₂ (aq) + 2NH₃ (g) + 2H₂O (l)       ΔH^Θ = +164 kJ mol⁻¹

What is the heat change, in kJ, when 100.0 g of aluminium is heated from 19.0 °C to 32.0 °C?

Specific heat capacity of aluminium: 0.90 J g⁻¹K⁻¹

When equal masses of X and Y absorb the same amount of energy, their temperatures rise by 5 °C and 10 °C respectively. Which is correct?

A student obtained the following data to calculate qq, using q=mcΔT

m=20.2g (±0.2g)

ΔT=10°C (±1°C)

c=4.18Jg−1K−1

What is the percentage uncertainty in the calculated value of q?

The enthalpy of combustion of ethanol is determined by heating a known mass of tap water in a glass beaker with a flame of burning ethanol.

Which will lead to the greatest error in the final result?

The enthalpy of combustion of a fuel was determined using the calorimeter shown. The final result was lower than the literature value.

Which factors could have contributed to this error?

I.   Not all heat from the combustion was transferred to the calorimeter.

II.  Incomplete combustion occurred.

III. The temperature probe touched the bottom of the calorimeter.