Student Force

A gaseous compound containing carbon and hydrogen was analyzed and found to consist of 83.65% carbon by mass. The molar mass of

steposvetlana [31]

Answer:

The molecular formula is C6H14

Explanation:

Step 1: Data given

Suppose the mass of compound = 100 grams

A compound contains:

Carbon = 83.65 % = 83.65 grams

Hydrogen = 16.35 % = 16.35 grams

Atomic mass of carbon = 12.01 g/mol

Atomic mass of hydrogen = 1.01 g/mol

Molar mass of compound = 86.2 g/mol

Step 2: Calculate moles

Moles = mass / molar mass

Moles carbon = 83.65 grams / 12.01 g/mol

Moles carbon = 6.965 moles

Moles hydrogen = 16.35 grams / 1.01 g/mol

Moles hydrogen = 16.19 moles

Step 3: Calculate mol ratio

We divide by the smallest amount of moles

C: 6.965 moles / 6.965 moles = 1

H = 16.19 moles / 6.965 moles = 2.33

This means for 1 mol C we have 2.33 moles H OR for 3 moles C we have 7 moles H

The empirical formula is C3H7

The molecular mass of this formula is 43.1 g/mol

Step 4: Calculate molecular formula

We have to multiply the empirical formula by n

n = 86.2 g/mol / 43.1 g/mol

n = 2

Molecular formula = 2*(C3H7) = C6H14

The molecular formula is C6H14

7 0

4 years ago

Sodium is a larger atom than lithium. List three reasons why this is true.

just olya [345]

Answer:

It is present in third period that's why its valance electrons are present in 3rd energy level.

Its atomic number is greater than lithium when compared in group wise.

There are more electrons in sodium to shield the outer valance electron thus nuclear attraction becomes weak and size increase.

Explanation:

The size of sodium is greater than lithium because atomic number of sodium is 11 and lithium is 3. Both are present in first group but sodium is present down to the lithium. As we move from top to bottom in a group atomic size increases with addition of electrons. The nuclear effect become weaker on valance electrons and atomic size increase. Same time shielding effect is also produces which shield the outer electrons from the influence of nucleus. While in case of lithium less electrons are present to shield the valance electrons.

As we note the position of both elements along period. The sodium is present in third period while lithium is present in second period. So, in case of sodium third energy level is involved. That's why its size is greater than lithium.

8 0

3 years ago

Select the ion. a) NO2 b)H2SO4 c) Al+3 ...?

Gemiola [76]

I believe the correct answer from the choices listed above is the third option. The ion would be Al+3. It is obvious because among the options, this is the only substance that has a charge. An ion is an atom or a molecule in which the total number of electrons is not equal to the total number of protons, giving the atom or molecule a net positive or negative electrical charge.

5 0

4 years ago

Read 2 more answers

2. A convergent boundary is

wel

Answer:

A. When two boundary plates are moving slowly toward each other.

3 0

3 years ago

If the rate of decrease for the partial pressure of N2H4N2H4 in a closed reaction vessel is 70 torr/htorr/h , what is the rate o

german

Answer:

$r_{NH_3}=140torr/h$

Explanation:

Hello,

In this case, the undergoing chemical reaction is:

$N_2H_4 (g) + H_2 (g) \rightarrow 2 NH_3$

Thus, in terms of pressures, the rate becomes:

$-r_{N_2H_4}=\frac{1}{2} r_{NH_3}$

Thus, the rate of change for the partial pressure of ammonia turns out:

$r_{NH_3}=2*(-r_{N_2H_4})\\r_{NH_3}=2*[-(-70torr/h)]\\r_{NH_3}=140torr/h$

The rate of decrease of partial pressure of urea is taken negative as it is a reactant whereas ammonia a product which has 2 as its stoichiometric coefficient.

Best regards.

7 0

3 years ago