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dybincka [34]
4 years ago
8

A chemical reaction gives off 1,500 kj of heat energy. about how many calories is this? (1 calorie = 4.18 joules)

Chemistry
2 answers:
Greeley [361]4 years ago
6 0
1500kj = 15x 10^5 j
1 calorie = 4.18 j
(15 x 10^5)/4.18= 3.58 x 10^5

Answer is a
Zanzabum4 years ago
3 0

Answer is: a. 3.6 x 10^5 calories.  

E = 1500 kJ; heat energy.

E = 1500 kJ · 1000 J/kJ.

E = 1500000 J = 1.5·10⁶ J.

E = 1.5·10⁶ J ÷ 4.18 J/cal.

E = 3.6·10⁵ cal.

Calorie (cal), or small calorie, is the amount of energy needed to heat one gram of water by one degree Celsius.

One small calorie is approximately 4.18 joules.

A calorie is a unit of energy.


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A cell was prepared by dipping a Cu wire and a saturated calomel electrode into 0.10 M CuSO4 solution. The Cu wire was attached
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Answer:

(a)  Cu²⁺ +2e⁻ ⇌ Cu

(c) 0.07 V  

Explanation:

(a) Cu half-reaction

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(c) Cell voltage

The standard reduction potentials for the half-reactions are+

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The equation for the cell reaction is

                                                                            E°/V

Cu²⁺(0.1 mol·L⁻¹) + 2e⁻ ⇌ Cu;                               0.34  

<u>2Hg + 2Cl⁻ ⇌ Hg₂Cl₂ + 2e⁻;                             </u> <u>-0.241 </u>

Cu²⁺(0.1 mol·L⁻¹) + 2Hg + 2Cl⁻ ⇌ Cu + Hg₂Cl₂;   0.10

The concentration is not 1 mol·L⁻¹, so we must use the Nernst equation

(ii) Calculations:  

T = 25 + 273.15 = 298.15 K

Q = \dfrac{\text{[Cl}^{-}]^{2}}{ \text{[Cu}^{2+}]} = \dfrac{1}{0.1} = 10\\\\E = 0.10 - \left (\dfrac{8.314 \times 298.15 }{2 \times 96485}\right ) \ln(10)\\\\=0.010 -0.01285 \times 2.3 = 0.10 - 0.03 = \textbf{0.07 V}\\\text{The cell potential is }\large\boxed{\textbf{0.07 V}}

 

3 0
3 years ago
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4 0
3 years ago
What is the chemical name for Iridium(V) Oxide?
goblinko [34]

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Names

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27 more rows

6 0
3 years ago
Read 2 more answers
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