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3 years ago

Problem 4

Chemistry

1 answer:

Hunter-Best [27]3 years ago

3 0

<h3>Answer:</h3>

1.93 g

<h3>Explanation:</h3>

<u>We are given;</u>

The chemical equation;

2C₂H₆(g) + 7O₂(g) → 4CO₂(g) + 6H₂O(l) ΔH = -3120 kJ

We are required to calculate the mass of ethane that would produce 100 kJ of heat.

From the equation given;

2 moles of ethane burns to produce 3120 Kilo joules of heat

Therefore;

Number of moles that will produce 100 kJ will be;

= (2 × 100 kJ) ÷ 3120 kJ)

= 0.0641 moles

But, molar mass of ethane is 30.07 g/mol

Therefore;

Mass of ethane = 0.0641 moles × 30.07 g/mol

= 1.927 g

= 1.93 g

Thus, the mass of ethane that would produce 100 kJ of heat is 1.93 g

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64. Which of the followings can dissociate in water?

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Answer:

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Explanation:

<h2>Reason :-</h2>

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2 years ago

Read 2 more answers

The substance argon has the following properties: normal melting point: 83.9 K normal boiling point: 87.4 K triple point: 0.68 a

Vsevolod [243]

Answer:

The final state of the substance is a gas.

The sample is initially a liquid. One or more phase changes will occur.

Explanation:

Let's consider the phase diagram for Argon (not to scale).

<em>A sample of argon is initially at a pressure of 49.6 atm and a temperature of 101.4 K. The pressure on the sample is reduced to 0.680 atm at a constant temperature of 101.4 K. Which of the following are true? Choose all that apply </em>

<em>The final state of the substance is a gas.</em> TRUE. At 0.680 atm and 101.4 K, the substance is a gas.

<em>The gas initially present will solidify.</em> FALSE. Initially, Ar is present as a liquid.

<em>The final state of the substance is a solid.</em> FALSE.

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5 0

4 years ago

An electric range burner weighing 699.0 grams is turned off after reaching a temperature of 482.0°C, and is allowed to cool down

jasenka [17]

Answer:

0.42 J/gºC

Explanation:

We'll begin by calculating the heat energy used to heat up the water. This can be obtained as follow:

Mass (M) of water = 560 g

Initial temperature (T₁) = 22.7 °C

Final temperature (T₂) = 80.3 °C.

Specific heat capacity (C) of water = 4.18 J/gºC

Heat (Q) absorbed =?

Q = MC(T₂ – T₁)

Q = 560 × 4.18 (80.3 – 22.7)

Q = 2340.8 × 57.6

Q = 134830.08 J

Finally, we shall determine the specific heat capacity of the burner. This can be obtained as follow:

Mass (M) of burner = 699 g

Initial temperature (T₁) = 482.0°C

Final temperature (T₂) = 22.7 °C

Heat (Q) evolved = – 134830.08 J

Specific heat capacity (C) of the burner =?

Q = MC(T₂ – T₁)

–134830.08 = 699 × C (22.7 – 482.0)

–134830.08 = 699 × C × –459.3

–134830.08 = –321050.7 × C

Divide both side by –321050.7

C = –134830.08 / –321050.7

C = 0.42 J/gºC

Therefore, the specific heat capacity of the burner is 0.42 J/gºC

8 0

3 years ago

Balance the following redox reaction in acidic solution. Zn(s)+MnO−4(aq)→ Zn+2(aq)+Mn+2(aq)

devlian [24]

Answer:

2MnO₄⁻ + 5Zn + 16H⁺ → 2Mn²⁺ + 8H₂O + 5Zn²⁺

Explanation:

To balance a redox reaction in an acidic medium, we simply follow some rules:

Split the reaction into an oxidation and reduction half.
By inspecting, balance the half equations with respect to the charges and atoms.
In acidic medium, one atom of H₂O is used to balance up each oxygen atom and one H⁺ balances up each hydrogen atom on the deficient side of the equation.
Use electrons to balance the charges. Add the appropriate numbers of electrons the side with more charge and obtain a uniform charge on both sides.
Multiply both equations with appropriate factors to balance the electrons in the two half equations.
Add up the balanced half equations and cancel out any specie that occur on both sides.
Check to see if the charge and atoms are balanced.

Solution

Zn + MnO₄⁻ → Zn²⁺ + Mn²⁺

The half equations:

Zn → Zn²⁺ Oxidation half

MnO₄⁻ → Mn²⁺ Reduction half

Balancing of atoms(in acidic medium)

Zn → Zn²⁺

MnO₄⁻ + 8H⁺ → Mn²⁺ + 4H₂O

Balancing of charge

Zn → Zn²⁺ + 2e⁻

MnO₄⁻ + 8H⁺ + 5e⁻→ Mn²⁺ + 4H₂O

Balancing of electrons

Multiply the oxidation half by 5 and reduction half by 2:

5Zn → 5Zn²⁺ + 10e⁻

2MnO₄⁻ + 16H⁺ + 10e⁻→ 2Mn²⁺ + 8H₂O

Adding up the two equations gives:

5Zn + 2MnO₄⁻ + 16H⁺ + 10e⁻ → 5Zn²⁺ + 10e⁻ + 2Mn²⁺ + 8H₂O

The net equation gives:

5Zn + 2MnO₄⁻ + 16H⁺ → 5Zn²⁺ + 2Mn²⁺ + 8H₂O

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3 years ago

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Answer:

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Explanation:

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