IB Chemistry Topic 4

This question is about an experiment to measure the enthalpy of combustion, ΔH_c, of ethanol, using the apparatus and setup shown. Which quantity is likely to be the most inaccurate due to the sources of error in this experiment?

• Mass of ethanol burnt

• Molecular mass of ethanol

• Mass of water

• Temperature change

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

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?

• Assuming the density of tap water is 1.0 g cm⁻³

• Assuming all the energy from the combustion will heat the water.

• Assuming the specific heat capacity of the tap water is 4.18 J g⁻¹ K⁻¹

• Assuming the specific heat capacity of the beaker is negligible

Tags

NGSS.HS-PS3-4

Two 100 cm³ aqueous solutions, one containing 0.010 mol NaOH and the other 0.010 mol HCl, are at the same temperature. When the two solutions are mixed the temperature rises by y °C. Assume the density of the final solution is 1.00 g cm⁻³. Specific heat capacity of water = 4.18 J g⁻¹ K⁻¹ What is the enthalpy change of neutralization in kJ mol⁻¹?

• A

• B

• C

• D

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

NGSS.HS-PS3-4

Which statement is correct for this reaction? Fe₂O₃ (s) + 3CO (g) → 2Fe (s) + 3CO₂ (g) ΔH = −26.6 kJ

• 13.3 kJ are released for every mole of Fe produced.

• 26.6 kJ are absorbed for every mole of Fe produced.

• 53.2 kJ are released for every mole of Fe produced.

• 26.6 kJ are released for every mole of Fe produced.

Tags

NGSS.HS-PS1-4

Match the following properties with their classification as either an intensive or extensive property.

• Temperature at which an object changes from solid to liquid

• Metallic

• Amount of matter in an object

• Melting point

• Color of an object

• Mass

• Appearance of an object

• Silver

the study of the structure, properties, composition, reactions, and preparation of carbon-containing compounds​ ​ (a)  

• Organic chemistry

• Catacoustics

• Abyssal

• Gluon

Tags

NGSS.HS-LS1-6

Which expression gives the mass, in g, of ethanol (C₂H₆O)required to produce 683.5 kJ of heat upon complete combustion?

(M_r for ethanol = 46.0, ΔH^θ_c=−1367 kJmol⁻¹)

• A

• B

• C

• D

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

NGSS.HS-PS3-4

When 25.0cm³ 0.100moldm⁻³ NaOH(aq) is mixed with 25.0cm³ 0.100moldm⁻³ HCl(aq) at the same temperature, a temperature rise, ∆T, is recorded. What is the expression, in kJ mol⁻¹, for the enthalpy of neutralisation? (Assume the density of the mixture = 1.00 g cm⁻³ and its specific heat capacity=4.18kJkg⁻¹K⁻¹ =4.18Jg⁻¹K⁻¹)

• A

• B

• C

• D

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

5.35g of solid ammonium chloride, NH₄Cl(s), was added to water to form 25.0g of solution. The maximum decrease in temperature was 14 K. What is the enthalpy change, in kJmol^-1, for this reaction? (Molar mass of NH₄Cl = 53.5gmol^-1; the specific heat capacity of the solution is 4.18 Jg^-1K^-1)

• A

• B

• C

• D

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

The enthalpy change for the reaction between zinc metal and copper(II) sulfate solution is −217 kJmol⁻¹. Which statement about this reaction is correct?

• The reaction is endothermic and the temperature of the reaction mixture initially rises.

• The reaction is endothermic and the temperature of the reaction mixture initially drops.

• The reaction is exothermic and the temperature of the reaction mixture initially rises.

• The reaction is exothermic and the temperature of the reaction mixture initially drops.

Tags

NGSS.HS-PS1-4