Given the following data: n2(g) + o2(g)→ 2no(g), δh=+180.7kj2no(g) + o2(g)→ 2no2(g), δh=−113.1kj2n2o(g) → 2n2(g) + o2(g), δh=−163.2kjuse hess's law to calculate δh for the following reaction: n2o(g)+no2(g)→3no(g)express the enthalpy in kilojoules to four significant digits.

ΔH = +155.6 kJ

Explanation:

The Hess' Law states that the enthalpy of the overall reaction is the sum of the enthalpy of the step reactions. To do the addition of the reaction, we first must reorganize them, to disappear with the intermediaries (substances that are not presented in the overall reaction).

If the reaction is inverted, the signal of the enthalpy changes, and if its multiplied by a constant, the enthalpy must be multiplied by the same constant. Thus:

N₂(g) + O₂(g) → 2NO(g) ΔH = +180.7 kJ

2NO(g) + O₂(g) → 2NO₂(g) ΔH = -113.1 kJ

2N₂O(g) → 2N₂(g) + O₂(g) ΔH = -163.2 kJ

The intermediares are N₂ and O₂, thus, reorganizing the reactions:

N₂(g) + O₂(g) → 2NO(g) ΔH = +180.7 kJ

NO₂(g) → NO(g) + (1/2)O₂(g) ΔH = +56.55 kJ (inverted and multiplied by 1/2)

N₂O(g) → N₂(g) + (1/2)O₂(g) ΔH = -81.6 kJ (multiplied by 1/2)

N₂O(g) + NO₂(g) → 3NO(g)

ΔH = +180.7 + 56.55 - 81.6

ΔH = +155.6 kJ

Purchases= 15,880 ounces

Explanation:

Giving the following information:

Production:

July= 7,900

August= 8,100

The direct materials required per unit are 2 ounces (oz.).

Desired ending inventory= 20% of the units of budgeted production in the following month.

Beginning inventory= 3,160 ounces

To calculate the direct material purchase, we need to use the following formula:

Purchases= production + desired ending inventory - beginning inventory

Purchases= 7,900*2 + (8,100*2)*0.2 - 3,160

Purchases= 15,880 ounces