Answer:
b). silver (Ag)
Explanation:
If you look at the periodic table, you just need to look at the atomic number of the element, because the atomic number tells you how many protons there are in the nucleus of the element.
But do be careful because some periodic tables have the molar mass at the top left corner, but the one I use has the atomic number at the top left corner, so make sure you look for the atomic number and not the molar mass.
I believe the answer is a balance or mechanical scale
The relation between the volume of the gas and the temperature is established by Charles's law. With a decrease in the temperature, the volume decreases by 45.7 mL. Thus, option c is correct.
<h3>What is Charle's law?</h3>
Charle's law states the direct relation present between the temperature and the volume of the gas. The law is given as:
V₁ ÷ T₁ = V₂ ÷ T₂
Given,
V₁ = 50 mL
T₁ = 303.15 K
T₂ = 277.15 K
Substituting the value the final volume is calculated as:
50 ÷ 303.15 = V₂ ÷ 277.15
V₂ = (50 × 277.15) ÷ 303.15
= 45.71 mL
Therefore, option c. 45.7 mL is the final volume.
Learn more about Charles law here:
brainly.com/question/16927784
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Answer:
90.3 kJ/mol
Explanation:
Let's consider the following thermochemical equation.
2 NO(g) + O₂(g) → 2 NO₂(g) ∆H°rxn = –114.2 kJ
We can find the standard enthalpy of formation for NO using the following expression.
∆H°rxn = 2 mol × ΔH°f(NO₂(g)) - 2 mol × ΔH°f(NO(g)) - 1 mol × ΔH°f(O₂(g))
∆H°rxn = 2 mol × ΔH°f(NO₂(g)) - 2 mol × ΔH°f(NO(g)) - 1 mol × 0 kJ/mol
∆H°rxn = 2 mol × ΔH°f(NO₂(g)) - 2 mol × ΔH°f(NO(g))
ΔH°f(NO(g)) = (2 mol × ΔH°f(NO₂(g)) - ∆H°rxn) / 2 mol
ΔH°f(NO(g)) = (2 mol × 33.2 kJ/mol + 114.2 kJ) / 2 mol
ΔH°f(NO(g)) = 90.3 kJ/mol
