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2 years ago

How much heat (in Joules) is needed to raise the temperature of 257g of ethanol (cethanol=2.4 J/g°C) by 49.1°C?

Chemistry

1 answer:

Sonbull [250]2 years ago

8 0

Answer:

Q = 30284.88 j

Explanation:

Given data:

Mass of ethanol = 257 g

Cp = 2.4 j/g.°C

Chnage in temperature = ΔT = 49.1°C

Heat required = ?

Solution:

Specific heat capacity:

It is the amount of heat required to raise the temperature of one gram of substance by one degree.

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

Now we will put the values in formula.

Q = 257 g× 2.4 j/g.°C × 49.1 °C

Q = 30284.88 j

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Questoin 2:

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2 years ago

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zavuch27 [327]

Answer:

71.5g

Explanation:

The reaction equation is given as:

C + O₂ → CO₂

Mass of C = 42g

Mass of O₂ = 52g

Unknown:

Mass of CO₂ produced = ?

Solution

Now to solve this problem, we have to find limiting reactant which is the one given in short supply in this reaction.

The extent of the reaction is controlled by this reactant.

Find the number of moles of the given species;

Number of moles = $\frac{mass}{molar mass}$

Number of moles of C = $\frac{42}{12}$ = 3.5mol

Number of moles of O₂ = $\frac{52}{32}$ = 1.63mol

Now;

From the balanced reaction equation;

1 mole of C reacted with 1 mole of O₂

We see that C is in excess and O₂ is the limiting reactant.

1 mole of O₂ will produce 1 mole of CO₂

So; 1.63mole of O₂ will produce 1.63 mole of CO₂

Mass of CO₂ = number of moles x molar mass

Molar mass of CO₂ = 44g/mol

Mass of CO₂ = 1.63 x 44 = 71.5g

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