Answer : The specific heat of the substance is 0.0936 J/g °C
Explanation :
The amount of heat Q can be calculated using following formula.

Where Q is the amount of heat required = 300 J
m is the mass of the substance = 267 g
ΔT is the change in temperature = 12°C
C is the specific heat of the substance.
We want to solve for C, so the equation for Q is modified as follows.

Let us plug in the values in above equation.


C = 0.0936 J/g °C
The specific heat of the substance is 0.0936 J/g°C
B. When scientific understanding changes.
Answer:
Fe²⁺(aq) + S²⁻(aq )⟶ FeS(s)
Step-by-step explanation:
Molecular Equation:
(NH₄)₂S(aq) + FeCl₂(aq) ⟶ 2NH₄Cl(aq) + FeS(s)
Ionic equation
:
2NH₄⁺(aq) + S²⁻(aq) + Fe²⁺(aq) + 2Cl⁻(aq) ⟶ 2NH₄⁺(aq) + 2Cl⁻(aq) + FeS(s)
Net ionic equation
:
Cancel all ions that appear on both sides of the reaction arrow (underlined).
<u>2NH₄⁺(aq)</u> + S²⁻(aq) + Fe²⁺(aq) + <u>2Cl⁻(aq)</u> ⟶ <u>2NH₄⁺(aq) </u>+ 2<u>Cl⁻(aq) </u>+ FeS(s)
Fe²⁺(aq) + S²⁻(aq )⟶ FeS(s)
1. B
2. C
3. E
4. D
5. A
6. B
7. A
8. E
9. A
Hope this helps!