Answer:

Molecular formula => C₃H₈O₃

Explanation:

From the question given above, the following data were obtained:

Carbon (C) = 39.12%

Hydrogen (H) = 8.75%

Oxygen (O) = 51.12%

Molar mass of compound = 92.09 g/mol

Molecular formula =?

Next, we shall determine the empirical formula of the compound. This can be obtained as follow:

C = 39.12%

H = 8.75%

O = 51.12%

Divide by their molar mass

C = 39.12 / 12 = 3.26

H = 8.75 / 1 = 8.75

O = 51.12 / 16 = 3.195

Divide by the smallest

C = 3.26 / 3.195 = 1

H = 8.75 / 3.195 = 2.7

O = 3.195 / 3.195 = 1

Thus, the empirical formula is CH₂.₇O

Finally, we shall determine the molecular formula of the compound. This can be obtained as follow:

Empirical formula = CH₂.₇O

Molar mass of compound = 92.09 g/mol

Molecular formula =?

Molecular formula = Empirical formula × n

Molecular formula = [CH₂.₇O]ₙ

92.09 = [12 + (2.7×1) + 16] × n

92.09 = 30.7n

Divide both side by 30.7

n = 92.09 / 30.7

n = 3

Molecular formula = [CH₂.₇O]ₙ

Molecular formula = [CH₂.₇O]₃

Molecular formula = C₃H₈O₃

I can give you four oxygen, selenium, sulfur, talarium hope this helps!

**Answer:**

Mass: 981.0 g

Density: 5.61 g/cm^3

Hardness: = 2.5 - 3

Unknown material: Chalcocite

**Answer:**

**The final temperature of the mixture is 22.3°C**

**Explanation:**

Assuming that the 120 g substance at 80°C is water, final temperature of the mixture can be determined using the formula:

Heat lost = Heat gained

Heat = mc∆T where m is mass, c is specific heat capacity of water, and ∆T is the temperature change =<em> Tfinal - Tinitial</em>.

Let the final temperature be T

Heat lost = 120 × c × (T - 80)

Heat gained = 3000 × c × ( T - 20)

Equating the heat lost and heat gained

120 × c × -(T - 80) = 3000 × c × (T - 20)

9600 - 120T = 3000T - 60000

60000 + 9600 = 3000T + 120T

69600 = 3120T

T = 69600/3120

T = 22.3°C

**Therefore, the final temperature of the mixture is 22.3°C**