Answer:
17,890 J
Explanation:
The amount of heat released by a gaseous substance when it condenses is given by the formula
where
n is the number of moles of the substance
is the latent heat of vaporization
The formula can be applied if the substance is at its vaporization temperature.
In this problem, we have:
n = 0.440 mol is the number of moles of steam
is the latent heat of vaporization of water
And the steam is already at 100C, so we can apply the formula:
What amount of heat absorbs 50 g of steel (ce = 0.115 cal / g. ° C) that
does its temperature vary by 25 ° C?
Answer:
143.75cal
Explanation:
Given parameters:
Mass of steel = 50g
Specific heat capacity of the steel = 0.115cal/g°C
Temperature = 25°C
Unknown:
Amount of heat = ?
Solution:
The amount of heat to cause this temperature change is dependent on mass and specific heat capacity of the substance.
Amount of heat = m C (ΔT)
m is the mass
c is the specific heat capacity
ΔT is the temperature change
Now insert the parameters and solve;
Amount of heat = 50 x 0.115 x 25
Amount of heat = 143.75cal
Answer:
pH = 12.15
Explanation:
To determine the pH of the HCl and KOH mixture, we need to know that the reaction is a neutralization type.
HCl + KOH → H₂O + KCl
We need to determine the moles of each compound
M = mmol / V (mL) → 30 mL . 0.10 M = 3 mmoles of HCl
M = mmol / V (mL) → 40 mL . 0.10 M = 4 mmoles of KOH
The base is in excess, so the HCl will completely react and we would produce the same mmoles of KCl
HCl + KOH → H₂O + KCl
3 m 4 m -
1 m 3 m
As the KCl is a neutral salt, it does not have any effect on the pH, so the pH will be affected, by the strong base.
1 mmol of KOH has 1 mmol of OH⁻, so the [OH⁻] will be 1 mmol / Tot volume
[OH⁻] 1 mmol / 70 mL = 0.014285 M
- log [OH⁻] = 1.85 → pH = 14 - pOH → 14 - 1.85 = 12.15
Answer:
First of all, the equation is typed wrong so it can easily be misinterpreted
Ethane (CH4) + Oxygen gas (O2) would give us Carbon Dioxide (CO2) and WATER (H2O)
CH4 + 2O2 -----> CO2 + 2H2O
And this is a combustion reaction since we have oxygen as a reactant and carbon dioxide and water as products.
