A chemist measures the enthalpy change ΔH during the following reaction: Fe(s) + 2HCl(g)-->FeCl2(s) + H2 ΔH=-157.0 kJ. Use this information to complete the table below. Round each of your answers to the nearest kJ/mol

Answer:

-314 kJ

+628 kJ

+157 kJ

Explanation:

The enthalpy change of a reaction measures the amount of heat that is lost or gained by it. If ΔH >0 the heat is gained, and the reaction is called endothermic, if ΔH<0, the heat is lost, and the reaction is called exothermic.

If the reaction is inverted, the value of ΔH is inverted too (the opposite endothermic reaction is exothermic), and if the reaction is multiplied by a constant, ΔH will be multiplied by it too.

1) 2Fe(s) + 4HCl --> 2FeCl2(s) + 2H2(g)

This reaction is the product of the given reaction by 2, so

ΔH = 2*(-157) = -314 kJ

2) 4FeCl2(s) + 4H2(g) --> 4Fe(s) + 8HCl(g)

This reaction is the inverted reaction given multiplied by 4, so

ΔH = 4*(157) = +628 kJ

3) FeCl2(s) + H2(g) --> Fe(s) + 2HCl

This reaction is the inverted reaction given, so

ΔH = +157 kJ

4 0

3 years ago

Help me please <br> Answer & exp.

nordsb [41]

Explanation:

Some Rules Regarding Oxidation Numbers:

- Hydrogen has oxidation number of + 1 except in hydrides where it is -1

- Oxygen has oxidation number of -2 except in peroxides where it is -1

- Some elements have fixed oxidation numbers. E.g Halogen group elements has oxidation number of -1

- Oxidation number of a compound is the sum total of the individual elements and a neutral compound has oxidation number of 0.

A. HI

Hydrogen has oxidation of + 1

Oxidation number of I:

1 + x = 0

x = -1

B. PBr3

Br has oxidation number of - 1

Oxidation number of Pb:

x + 3 (-1) = 0

x = + 3

C. KH

Hydrogen has oxidation of + 1

Oxidation number of K:

1 + x = 0

x = -1

D. H3PO4

Hydrogen has oxidation number of + 1

Oxygen has oxidation number of -2

Oxidation number of P:

3(1) + x + 4(-2) = 0

3 + x - 8 =0

x = 5

8 0

2 years ago