I have posted the answetr in this picture.
Answer:
1. C
2. C
3. A
4. C
5. True
6. C
Explanation:
1. C The answer is conduction because the heat was transferred through direct contact.
2. C The answer convection because the heat was transferred through a medium (liquid/gas).
3. A The answer is conduction because the heat was transferred through direct contact.
4. C The answer is radiation because the heat was transferred through thermal emission.
5. True. This is because the air that is warmed rises, causing the cool air to replace it. You can picture it like the scenario in question 2.
6. C
I’m not totally sure but I think the answer is B
The reaction is:
X + Y → W + Z
Chemical energy of reactant X = 199.3 J = Ux
Chemical energy of reactant Y = 272.3 J = Uy
Chemical energy of Product W = 41.9 J = Uw
Chemical energy of Product Z = ? = Uz
Where reaction loses energy = 111.6 J = ΔU
By using the equation:
(Ux + Uy) – (Uw + Uz) = ΔU
Ux + Uy – Uw – Uz = ΔU
Uz = Ux + Uy – Uw –ΔU
Uz = 199.3 + 272.3 – 41.9 – 111.6
Uz = 318.1 J
Product Z must contain 318.1 J chemical energy.
Answer:
Mass = 2.355 g
Explanation:
Given data:
Mass of K₂O needed = ?
Mass of KNO₃ produced = 5.00 g
Solution:
Chemical equation:
K₂O + Ca(NO₃)₂ → CaO + 2KNO₃
Number of moles of KNO₃:
Number of moles = mass/molar mass
Number of moles = 5.00 g/ 101.1 g/mol
Number of moles = 0.05 mol
now we will compare the moles of KNO₃ and K₂O.
KNO₃ : K₂O
2 : 1
0.05 : 1/2×0.05 = 0.025 mol
Mass of potassium oxide needed in gram:
Mass = number of moles × molar mass
Mass = 0.025 mol × 94.2 g/mol
Mass = 2.355 g