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3 years ago

Q = smT

Chemistry

1 answer:

Effectus [21]3 years ago

4 0

Answer:

The heat required is 1262.91 joules or 1.26 kilojoules.

Explanation:

The quantity of heat (Q) required to raise the temperature of a substance depends on its Mass (M), specific heat capacity (C) and change in temperature (Φ)

Thus, Q = MCΦ

Since,

Q = ?

Mass of aluminum sample = 33.0g

C = 0.89 J/g℃

Φ = (Final temperature - Initial temperature)

= 68°C - 25°C = 43°C

Then, Q = MCΦ

Q = 33.0g x 0.89 J/g℃ x 43°C

Q = 1262.91 J

Since the heat in joules is 1262.91, obtain heat in kilojoules.

If 1000 joules = 1 kilojoules

1262.91 joules = Z

To get Z, cross multiply

Z x 1000 = 1262.91 x 1

1000Z = 1262.91

Z = 1262.91 / 1000

Z = 1.26291 kilojoules (when placed as 3 significant figures, Z is 1.26 kilojoules)

Thus, the heat required is 1262.91 joules or 1.26 kilojoules.

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carbon disulfide is formed by the reaction of coke (carbon) with sulfur dioxide. how many moles of cs2 will be generated if 8.0

DerKrebs [107]

The balanced chemical reaction:

5C + 2SO2 → CS2 + 4CO

We are given the amount of coke to be used for the reaction. This will be the starting point for the calculations.

8 mol C ( 1 mol CS2 / 5 mol C ) = 1.6 mol CS2

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3 years ago

A 1.0 L buffer solution is 0.300 M HC2H3O2 and 0.045 M LiC2H3O2. Which of the following actions will destroy the buffer?

zheka24 [161]

Answer:

b) Adding 0.075 moles of HCl

Explanation:

A buffer is defined as the aqueous mixture of a weak acid and its conjugate base or vice versa (Weak base with its conjugate acid).

The buffer of the problem is the acetic acid / lithium acetate.

The addition of any moles of the acid and the conjugate base will not destroy the buffer, just would change the pH of the buffer. Thus, a and c will not destroy the buffer.

The addition of an acid (HCl) or a base (NaOH), produce the following reactions:

HCl + LiC₂H₃O₂ → HC₂H₃O₂ + LiCl

The acid reacts with the conjugate base to produce the weak acid.

And:

NaOH + HC₂H₃O₂ →NaC₂H₃O₂ + H₂O

The base reacts with the weak acid to produce conjugate base.

As the buffer is 1.0L, the moles of the species of the buffer are:

HC₂H₃O₂ = 0.300 moles

LiC₂H₃O₂ = 0.045 moles

The reaction of HCl with LiC₂H₃O₂ consume all LiC₂H₃O₂ -because there are an excess of moles of HCl that react with all LiC₂H₃O₂-

As you will have just HC₂H₃O₂ after the reaction, the addition of b destroy the buffer.

In the other way, 0.0500 moles of NaOH react with the HC₂H₃O₂ but not consuming all HC₂H₃O₂, thus d doesn't destroy the buffer.

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4 years ago

An unknown compound is treated at 0o C with bromine in the dark (reaction 1). The predominant product of this reaction is treate

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Answer:

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Explanation:v

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3 years ago

Which example is a weak base? ethyl alcohol, ammonia, potassium hydroxide or vinegar?

BlackZzzverrR [31]

Answer:

potassium

Explanation:

b/c electronegativitu

7 0

3 years ago

A vessel with a volume of 32. 5 l contains 2. 80 g of n2 gas, 0. 403 g of h2 gas, and 79. 9 g of ar gas. at 25°c, what is the to

d1i1m1o1n [39]

The total pressure of the gases in the vessel is found out by using the partial pressures of individual gases and adding them up. The total pressure of the gases in the vessel is 1.72 atm.

The Partial pressure of the gases is the individual pressure of the gases present in a vessel containing a mixture of gases. The total pressure can be found out by adding partial pressure of all gases.

Given:

Volume of vessel, V= 32.5L

Mass of Nitrogen gas = 2.8g

Mass of Hydrogen gas = 0.403g

Mass of Argon gas = 79.9g

We know that:

Molar Mass of Nitrogen gas = 28g

Molar Mass of Hydrogen gas = 2g

Molar Mass of Argon gas = 40g

∴ Moles of gas = Given mass / Molar mass

∴ Using the Ideal Gas Equation:

PV = nRT

where, P is the Pressure of gas

V is the volume of gas

n is the moles of gas

R is the Universal Gas constant

T is the temperature

Applying the above equation of all three gases indivudually,

∴ For Nitrogen,

P₁V = n₁RT

⇒ P₁ × 32.5 = 2.8/28 × 0.082 × 298

⇒ P₁ = 0.07atm

∴ For Hydrogen,

P₂V = n₂RT

⇒ P₂ × 32.5 = 0.4/2 × 0.082 × 298

⇒ P₂ = 0.15 atm

∴ For Argon,

P₃V = n₃RT

⇒ P₃ × 32.5 = 79.9/40 × 0.082 × 298

⇒ P₃ = 1.5 atm

∴ Total pressure of vessel, P = P₁ + P₂ + P₃

P = 1.72 atm

The total pressure of the gases in the vessel is 1.72 atm.

Learn more about Partial pressure here, brainly.com/question/23841760

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1 year ago