In a closed system containing three different gases as shown, X2 + Y2 = 2XY

A system conducts 50. J heat to the surroundings while delivering 20. J of work. What is the change in internal energy

Alexeev081 [22]

1. “what forms of energy conversions occur during the process of photosynthesis? (How does energy transform?) 2. What is missing from the food web but is essential to maintain equilibrium? A. Soil B.water C. Decomposers D. Oxygen

8 0

2 years ago

What is the number of copper atom in one naira coin which weight is 7.3g a sum of the material is 86%

Step2247 [10]

Answer:

5.9x10²² atoms of Cu are in one naira coin

Explanation:

To solve this question we need to find the mass of Copper. Then, using its molar mass (Cu = 63.546g/mol) we must find the moles of Cu and its atoms using Avogadro's number:

Mass Cu:

7.3g * 86% = 6.278g is the mass of Cu.

Moles Cu:

6.278g * (1mol / 63.546g) = 0.099moles Cu

Atoms Cu:

0.099moles Cu * (6.022x10²³atoms / 1mol) =

<h3>5.9x10²² atoms of Cu are in one naira coin</h3>

4 0

2 years ago

90 POINTSSSS!!!

Katarina [22]

Answer:

$\large \boxed{\text{-2043.96 kJ/mol}}$

Explanation:

Assume the reaction is the combustion of propane.

Word equation: propane plus oxygen produces carbon dioxide and water

Chemical eqn: C₃H₈(g) + O₂(g) ⟶ CO₂(g) + H₂O(g)

Balanced eqn: C₃H₈(g) + 5O₂(g) ⟶ 3CO₂(g) + 4H₂O(g)

(a) Table of enthalpies of formation of reactants and products

$\begin{array}{cc}\textbf{Substance} & \textbf{$\Delta_{\text{f}}$H/(kJ/mol}) \\\text{C$_{3}$H$_{8}$(g)} & -103.85 \\\text{O}_{2}\text{(g)} & 0 \\\text{CO}_{2}\text{(g)} & -393.51 \\\text{H$_{2}$O(g)} & -241.82\\\end{array}$

(b)Total enthalpies of reactants and products

$\Delta_{\text{rxn}}H^{\circ} = \sum \left( \Delta_{\text{f}} H^{\circ} \text{products}\right) - \sum \left (\Delta_{\text{f}}H^{\circ} \text{reactants} \right)\\= \text{-2147.81 kJ/mol - (-103.85 kJ/mol)}\\= \text{-2147.81 kJ/mol + 103.85 kJ/mol}\\= \textbf{-2043.96 kJ/mol}\\\text{The enthalpy change is $\large \boxed{\textbf{-2043.96 kJ/mol}}$}$