How much thermal energy must be added to a 87.5 g sample of ice at -25oC completely melt the entire sample? As part of your work
1 answer:
Answer:
4.6 kJ
Explanation:
The energy required to raise the temperature of a substance from its initial temperature to a final temperature is given by:
Q = mcΔT
Where Q = energy, c = specific heat capacity of substance and ΔT = final temperature - initial temperature
Given that:
c = 2.1 kJ/kg°C, m = 87.5 = 0.0875 kg, ΔT = final temperature - initial temperature = 0 - (-25) = 25
Q = 0.0875 * 2.1 *25
Q = 4.6 kJ
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Answer:
Mass of aluminium in sample = 3.591 g ≅ 3.6 grams
Explanation:
Given that, A sample of aluminum absorbs 50.1 J of heat, upon which the temperature of the sample increases from 20.0°C to 35.5°C.
the specific heat of aluminum is 0.900 J/g- °C
The relation between heat absorbed and change in temperature is given by, Q = msΔT.
where Q = heat absorbed
m = mass of the substance
s = specific heat of substance
ΔT = change in temperature
Now, in our case, Q = 50.1 J ; s = 0.900 J/g- °C; ΔT= 35.5-20 = 15.5°C
⇒ m =
⇒ m = = 3.591 g ≅ 3.6 g
⇒ m ≅ 3.6 g
Answer : Option D) The pH of the solution is 8.0.
Explanation : pOH of a solution is a measure of hydroxide ion concentration in a particular solution. It gives the measure of alkalinity of a solution. Normally, aqueous solutions at 25°C have pOH which is less than 7 are usually alkaline, when pOH is found to be greater than 7 then they are acidic and when pOH will be equal to 7 then it is neutral.
pH + pOH = 14, this relationship is used to find pH of any unknown solution with given pOH value,
Here, we known pOH is 6.0, so we get,
pH = 14 - 6 = 8.0;
Hence, the pH will be 8.0.