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Nezavi [6.7K]
3 years ago
9

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

, sketch a labelled heating curve. Circle the portion of the curve that is the focus of this question.
Chemistry
1 answer:
Maurinko [17]3 years ago
6 0

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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If 5.32 mols N2 and 15.8 mols H2 react together, what mass NH3 can be
hodyreva [135]

Answer:

2.87 gram

N2 is the limiting agent

Explanation:

We will find out if there is sufficient N2 and h2 to produce NH3

a) For 2.36 grams of N2

Molar mass of N2 = 28.02

Number of moles of N2 in 2.36 grams = 2.36/28.02

Mass of NH3 = 17.034 g

Now NH3 produced form 2.36 grams of N2 =  

2.36/28.02 * 2 * 17.034 = 2.87 g NH3

b) For 1.52 g of H2  

NH3 produced = 1.52/2.016 * (2/3) * 17.034 = 8.56

N2 Is not enough to produce 2.87 g of NH3 and also H2 is not enough to make 8.56 g of NH3.  

N2 is the limiting agent as it has smaller product mass

3 0
2 years ago
Which of the following atoms are isotopes? 22Na 22Ne 22Na 22Mg 24Na
Dima020 [189]
Na22 and Na24 are isotopes 
8 0
3 years ago
Is a forward or reverse reaction favored?
Alex Ar [27]

Answer:

(a) CH_3COOH \rightleftharpoons CH_3COO^-+ H^+: reverse reaction is favored.

(b) AgCl \rightleftharpoons Ag^+ + Cl^-: reverse reaction is favored.

(c) Al(OH)_3 \rightleftharpoons Al^{3+} + 3OH^-: reverse reaction is favored.

(d) A+B\rightleftharpoons C: forward reaction is favored.

Explanation:

Hello,

(a) CH_3COOH \rightleftharpoons CH_3COO^-+ H^+:

In this case, since the Ka is lower than 1, we infer the reverse reaction is favored since the reactant (acetic acid) will tend to have a higher concentration.

(b) AgCl \rightleftharpoons Ag^+ + Cl^-:

In this case, since the Ka is lower than 1, we infer the reverse reaction is favored since the reactant (silver chloride) will tend to have a higher concentration.

(c) Al(OH)_3 \rightleftharpoons Al^{3+} + 3OH^-

In this case, since the Ka is lower than 1, we infer the reverse reaction is favored since the reactant (aluminium hydroxide) will tend to have a higher concentration.

(d) A+B\rightleftharpoons C

In this case, since the Ka is greater than 1, we infer the forward reaction is favored since the product (C) will tend to have a higher concentration.

Regards.

6 0
3 years ago
How many grams of potassium chloride are required to make 250 ml of a 0.75 m kcl solution?
DedPeter [7]

Answer:

The solution would need 13.9 g of KCl

Explanation:

0.75 m, means molal concentration

0.75 moles in 1 kg of solvent.

Let's think as an aqueous solution.

250 mL = 250 g, cause water density (1g/mL)

1000 g have 0.75 moles of solute

250 g will have (0.75 . 250)/1000 = 0.1875 moles of KCl

Let's convert that moles in mass (mol . molar mass)

0.1875 m . 74.55 g/m = 13.9 g

7 0
3 years ago
Which of the following is a polar molecule?
mixer [17]

the answer is option b


7 0
3 years ago
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