What is one way to test weather an unknown solution is acidic or basic ?

A 21.82 gram sample of an organic compound containing C, H and O is analyzed by combustion analysis and 21.33 grams of CO2 and 4

morpeh [17]

Answer: The molecular formula for the given organic compound is $C_2H_2O_4$

Explanation:

The chemical equation for the combustion of hydrocarbon having carbon, hydrogen and oxygen follows:

$C_xH_yO_z+O_2\rightarrow CO_2+H_2O$

where, 'x', 'y' and 'z' are the subscripts of Carbon, hydrogen and oxygen respectively.

We are given:

Mass of $CO_2=21.33g$

Mass of $H_2O=4.366g$

We know that:

Molar mass of carbon dioxide = 44 g/mol

Molar mass of water = 18 g/mol

For calculating the mass of carbon:

In 44g of carbon dioxide, 12 g of carbon is contained.

So, in 21.33 g of carbon dioxide, $\frac{12}{44}\times 21.33=5.82g$ of carbon will be contained.

For calculating the mass of hydrogen:

In 18g of water, 2 g of hydrogen is contained.

So, in 4.366 g of water, $\frac{2}{18}\times 4.366=0.485g$ of hydrogen will be contained.

Mass of oxygen in the compound = (21.82) - (5.82 + 0.485) = 15.515 g

To formulate the empirical formula, we need to follow some steps:

Step 1: Converting the given masses into moles.

Moles of Carbon = $\frac{\text{Given mass of Carbon}}{\text{Molar mass of Carbon}}=\frac{5.82g}{12g/mole}=0.485moles$

Moles of Hydrogen = $\frac{\text{Given mass of Hydrogen}}{\text{Molar mass of Hydrogen}}=\frac{0.485g}{1g/mole}=0.485moles$

Moles of Oxygen = $\frac{\text{Given mass of oxygen}}{\text{Molar mass of oxygen}}=\frac{15.515g}{16g/mole}=0.969moles$

Step 2: Calculating the mole ratio of the given elements.

For the mole ratio, we divide each value of the moles by the smallest number of moles calculated which is 0.485 moles.

For Carbon = $\frac{0.485}{0.485}=1$

For Hydrogen = $\frac{0.485}{0.485}=1$

For Oxygen = $\frac{0.969}{0.485}=1.99\approx 2$

Step 3: Taking the mole ratio as their subscripts.

The ratio of C : H : O = 1 : 1 : 2

Hence, the empirical formula for the given compound is $C_1H_{1}O_2=CHO_2$

For determining the molecular formula, we need to determine the valency which is multiplied by each element to get the molecular formula.

The equation used to calculate the valency is :

$n=\frac{\text{molecular mass}}{\text{empirical mass}}$

We are given:

Mass of molecular formula = 90.04 g/mol

Mass of empirical formula = 45 g/mol

Putting values in above equation, we get:

$n=\frac{90.04g/mol}{45g/mol}=2$

Multiplying this valency by the subscript of every element of empirical formula, we get:

$C_{(1\times 2)}H_{(1\times 2)}O_{(2\times 2)}=C_2H_2O_4$

Thus, the molecular formula for the given organic compound is $C_2H_2O_4$

4 0

3 years ago

Which of the following organelles directs of the other parts of the cell?

Natalija [7]

Answer:A

Explanation: because The nucleus directs all of the cell's activities, including reproduction.

6 0

3 years ago

Read 2 more answers

which of these equations is balanced? A. 2Nac1+H2so4--->Na2so4+2Hc1 B. 2cao+H20-->CaC0h)2 C. H20+co-->h2c03 D. MN+FE--&

klemol [59]

The answer will be a because it's balance

5 0

3 years ago

What volume of 0.20 M solution of HCI will be required to neutralize 10.0 mL of a 0.60 M

tatyana61 [14]

Answer:

30ml

Explanation:

Chcl.Vhvl=Ckoh.Vkoh

4 0

2 years ago

1) ΔS depends not merely on q but on ______ . Although there are many possible paths that could take a system from its initial t

Rus_ich [418]

Answer:

1) qrev/ reversible/ has only one particular value/ regardless of;

2) 1 mol of H₂(g) at 0ºC

3) a phase change/ remains constant/ increase

Explanation:

1) The change can occur in a reversible or an irreversible process. When the change is reversible, the system and the surroundings can be restored to their original state by exactly reversing the change. In an irreversible process, that is not possible.

The entropy variation (ΔS) is calculated only in the reversible process because, in the irreversible one, it's difficult to determine it. So, ΔS depends on qrev, which is the heat for the reversible process.

There is only one reversible isothermal path between two states, that's why it's easy to calculate ΔS for it.

The value of ΔS doesn't depend on the path, but only on the initial and the final states, so ΔS has only one particular value regardless of the path taken between states.

2) The entropy is the measure of the disorganization of a system, so when the molecules are more distant and vibrating, the entropy is higher (Sgas > Sliquid > Ssolid), and when the temperature increases, the entropy decreases (ΔS = qrev/T), so 1 mol of H₂(g) at 0ºC has the greatest entropy.

3) During a phase change, for a pure substance, the temperature remains constant, until all the substance changes for the other phase. The entropy is the measure of the disorganization of a system, so when the degrees of freedom and motion of the molecules increase, the system becomes more disorganized, so the entropy increases.

4 0

3 years ago