1. Which of the following weighs least?

Glycerol (molar mass 92.09 g/mol) has been suggested for use as an alternative fuel. The enthalpy of combustion, Δ

victus00 [196]

The mass of glycerol to that would need to be combusted to heat 500.0g of water from 20.0°C to 100.0°C is; 9.32 grams.

We must establish the fact that energy is neither created nor destroyed.

Therefore, the amount of heat absorbed by water is equal to the amount of heat released by the combustion of glycerol.

Total heat absorbed by water, H(water) is;

Q(water) = m C (T2 - T1)

Q(water) = 500 × 4.184 × (100-20)

Q(water) = 167.36 kJ

Consequently, the quantity of heat evolved by the combustion of glycerol is;

Q(glycerol) = 167,360 J = n × ΔH°comb

where, n = no. of moles of glycerol.

167.36 kJ= n × 1654 kJ/mole

n = 167.36/1654

n = 0.1012 moles of glycerol.

Therefore, mass of glycerol combusted, m is;

m = n × Molar mass

m = 0.1012 × 92.09

m = 9.32 g.

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6 0

2 years ago

A chemist wants to extract copper metal from copper chloride solution. The chemist places 0.50 grams of aluminum foil in a solut

Irina-Kira [14]

Answer:

Approximately 0.36 grams, because copper (II) chloride acts as a limiting reactant.

Explanation:

It is a stichiometry problem.

We should write the balance equation of the mentioned chemical reaction:

2Al + 3CuCl₂ → 3Cu + 2AlCl₃.

It is clear that 2.0 moles of Al foil reacts with 3.0 moles of CuCl₂ to produce 3.0 moles of Cu metal and 2.0 moles of AlCl₃.

Also, we need to calculate the number of moles of the reported masses of Al foil (0.50 g) and CuCl₂ (0.75 g) using the relation:

n = mass / molar mass

The no. of moles of Al foil = mass / atomic mass = (0.50 g) / (26.98 g/mol) = 0.0185 mol.

The no. of moles of CuCl₂ = mass / molar mass = (0.75 g) / (134.45 g/mol) = 5.578 x 10⁻³ mol.

From the stichiometry Al foil reacts with CuCl₂ with a ratio of 2:3.

∴ 3.85 x 10⁻³ mol of Al foil reacts completely with 5.578 x 10⁻³ mol of CuCl₂ with (2:3) ratio and CuCl₂ is the limiting reactant while Al foil is in excess.

From the stichiometry 3.0 moles of CuCl₂ will produce the same no. of moles of copper metal (3.0 moles).
So, this reaction will produce 5.578 x 10⁻³ mol of copper metal.
Finally, we can calculate the mass of copper produced using:

mass of Cu = no. of moles x Atomic mass of Cu = (5.578 x 10⁻³ mol)(63.546 g/mol) = 0.354459 g ≅ 0.36 g.

So, the answer is:

Approximately 0.36 grams, because copper (II) chloride acts as a limiting reactant.

5 0

3 years ago

One mole of copper(ii) sulfate, cuso4, contains ________ o atoms.

Ierofanga [76]

According to avogadro constant, the number of units in one mole of any substance contain 6.022 x10 ^23 atoms

therefore the number of o atoms in one mole of CuSO4 = 6.022 x 10 ^ 23

6 0

2 years ago

Read 2 more answers

Two protons and two neutrons are released as a result of this reaction.

Murljashka [212]

Answer: The particle released in the given reaction is one alpha particle

Explanation:

In a nuclear reaction, the total mass and total atomic number remains the same.

For the given fission reaction:

$^{222}_{86}\textrm{Rn}\rightarrow ^A_Z\textrm{X}+^{218}_{84}\textrm{Po}$

To calculate A:

Total mass on reactant side = total mass on product side

222 = A + 218

A = 4

To calculate Z:

Total atomic number on reactant side = total atomic number on product side

86 = Z + 84

Z = 2

The isotopic symbol of unknown element is $_{2}^{4}\textrm{He}$ . Another name of helium atom is alpha particle.

Hence, the particle released in the given reaction is one alpha particle

3 0

3 years ago

Read 2 more answers

Zinc metal is produced by heating solid zinc sulfide with solid wine witte resulting in liquid zinc and sulfur dioxide gas Write

elena-s [515]

Answer:

The balance chemical equation can be given as:

$ZnS(s)+ZnSO_4(aq)\overset{heat}\rightarrow 2Zn(s)+2SO_2(g)$

Explanation:

When zinc sulfide is allowed to react with zinc sulfate it gives zinc metal and sulfur dioxide gas as a product.The balance chemical equation can be given as:

$ZnS(s)+ZnSO_4(aq)\overset{heat}\rightarrow 2Zn(s)+2SO_2(g)$

According to reaction we can see when 1 mol of zinc sulfide reacts with 1 mol of zinc sulfate it forms 2 moles of zinc metal and 2 moles of sulfur dioxide gas.

4 0

3 years ago