Answer:
Exothermic reactions feel hot
Endothermic reactions feel cool
Explanation:
In an exothermic reaction, heat is given out by the system. The energy of the reactants is greater than that of the products hence the excess energy is given off as heat. The reaction vessel feels hot.
In an endothermic reaction, the energy of products is greater than that of the reactants hence energy is taken into the system and the reaction vessel feels cool.
Molar mass of :
O2 = 16 * 2 = 32 g/mol
CO2 = 12 + 16 * 2 = 44 g/mol
<span>Balanced chemical equation :
</span>
1 CH4 +
2 O2 =
1 CO2 +
2 H2O
↓ ↓
2 moles 1 mole
2* 32 g O2 ----------> 1* 44 g CO2
x g O2 ------------> 10.0 g CO2
44 x = 2 * 32*10.0
44 x = 640
of O2
Answer:
-138.9 kJ/mol
Explanation:
Step 1: Convert 235.8°C to the Kelvin scale
We will use the following expression.
K = °C + 273.15 = 235.8°C + 273.15 = 509.0 K
Step 2: Calculate the standard enthalpy of reaction (ΔH°)
We will use the following expression.
ΔG° = ΔH° - T.ΔS°
ΔH° = ΔG° / T.ΔS°
ΔH° = (-936.92kJ/mol) / 509.0K × 0.51379 kJ/mol.K
ΔH° = -3.583 kJ (for 1 mole of balanced reaction)
Step 3: Convert -9.9°C to the Kelvin scale
K = °C + 273.15 = -9.9°C + 273.15 = 263.3 K
Step 4: Calculate ΔG° at 263.3 K
ΔG° = ΔH° - T.ΔS°
ΔG° = -3.583 kJ/mol - 263.3 K × 0.51379 kJ/mol.K
ΔG° = -138.9 kJ/mol
Answer:
A substance which burns in air and tends to produce heat and light is known as Combustible substances. Non-combustible substances are certain substances which are not combustible in the presence of air. Will not burn on being exposed to flame.
b, the sunlight decreases because the sun is tilted on an axis and towards the fall and winter times, it gets shorter
