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2 years ago

A compound is made up of 80.0 % C and 20.0 % H. Its molar mass is 30.0 g. What is its molecular formula?

Chemistry

1 answer:

Greeley [361]2 years ago

8 0

Answer:

Molecular formula = C₂H₆

Explanation:

Given data:

Percentage of hydrogen = 20.0 %

Percentage of carbon = 80.0 %

Molar mass = 30.0 g

Empirical formula = ?

Solution:

Number of gram atoms of H = 20 / 1.01 = 19.8

Number of gram atoms of C = 80 /12 = 6.7

Atomic ratio:

C : H

6.7/6.7 : 19.8/6.7

1 : 3

C : H = 1 : 3

Empirical formula is CH₃.

Molecular formula:

Molecular formula = n (empirical formula)

n = molar mass of compound / empirical formula mass

Empirical formula = CH₃ = 12×1 +3×1.01 = 15.03 g/mol

n = 30 g/mol / 15.03 g/mol

n = 2

Molecular formula = n (empirical formula)

Molecular formula = 2 (CH₃)

Molecular formula = C₂H₆

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jok3333 [9.3K]

Answer:

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Mo3+ - is Paramagnetic

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For Au+ is not paramagnetic

c) Mn - [Ar] 3d5 4s2

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d)Hf -[Xe] 4f¹⁴ 5d² 6s²

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Explanation:

An atom becomes positively charged when it looses an electron.

Diamagnetism in atom occurs whenever two electrons in an orbital paired equalises with a total spin of 0.

Paramagnetism in atom occurs whenever at least one orbital of an atom has a net spin of electron. That is a paramagnetic electron is just an unpaired electron in the atom.

Here is a twist even if an atom have ten diamagnetic electrons, the presence of at least one paramagnetic electron, makes it to be considered as a paramagnetic atom.

Simply put paramagnetic elements are one that have unpaired electrons, whereas diamagnetic elements do have paired electron.

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3 years ago

PbSO4, Spell out the full name of the compound.

andreyandreev [35.5K]

Answer:

Lead (II) Sulfate

Explanation:

Don't forget to add the (II) marking indicating that lead has a charge of 2+ (because Sulfate has a charge of 2-, balancing the ion).

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2 years ago

Calculate the amount of heat lost by 23 g of water when its temperature drops from 68.0°C to 31.0°C. The specific heat of water

34kurt

Answer:

3557J is the heat lost by the water

Explanation:

Using the equation:

Q = m*C*ΔT

Where Q is change in heat

m is mass of substance (23g of water)

C is specific heat of the substance (4.18J/g°C)

And ΔT is change in temperature (68.0°C - 31.0°C = 37.0°C)

we can find the amount of heat lost as follows:

Q = 23g*4.18J/g°C*37°C

Q =

3557J is the heat lost by the water

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3 years ago

3H2 + N2 —> 2NH3 .

In-s [12.5K]

Answer:

$\boxed{1.26 \times 10^{20} \text{ molecules NH}_{3}}$

Explanation:

We will need a balanced chemical equation with masses, moles, and molar masses.

1. Gather all the information in one place:

M_r: 2.016 17.03

3H₂ + N₂ ⟶ 2NH₃

m/g: 6.33 × 10⁻⁴

2. Calculate the moles of H₂

$\text{Moles of H}_{2} = 6.33 \times 10^{-4}\text{ g H}_{2} \times \dfrac{\text{1 mol H}_{2}}{\text{2.016 g H}_{2}} = 3.140 \times 10^{-4} \text{ mol H}_{2}$

3. Calculate the moles of NH₃

The molar ratio is 2 mol NH₃/3 mol H₂.

$\text{Moles of NH}_{3} = 3.140 \times 10^{-4} \text{ mol H}_{2} \times \dfrac{\text{2 mol NH}_{3}}{\text{3 mol H}_{2}} = 2.093 \times 10^{-4}\text{ mol NH}_{3}$

4. Calculate the molecules of NH₃

There are 6.022 × 10²³ molecules of NH₃/1 mol NH₃.

$\text{Molecules of NH}_{3} = 2.093 \times 10^{-4}\text{ mol NH}_{3} \times \dfrac{6.022 \times 10^{23}\text{ molecules NH}_{3}}{\text{1 mol NH}_{3}}\\= 1.26 \times 10^{20}\text{ molecules NH}_{3}\\\text{The reaction produces } \boxed{\mathbf{1.26 \times 10^{20}} \textbf{ molecules NH}_{3}}$

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3 years ago

Zn(s)+2HCl(aq)= Zncl2(aq)+H2(g)

algol13

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2.5 M HCl = 2.5 mol HCl / L soln

0.306 mol HCl / 2.5 mol HCl/L son = 0.1224 L soln needed

M1V1 = M2V2
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3 years ago