Internal energy is denoted by the letter U. True or false

3.5g of a Certain compound X, known to be made of carbon, hydrogen, and perhaps oxygen, and to have a molecular molar mass of 15

shutvik [7]

Answer:

C₅H₁₀O₅

Explanation:

1. Calculate the mass of each element in 2.78 mg of X.

(a) Mass of C

$\text{Mass of C} = \text{5.13 g CO}_{2}\times \dfrac{\text{12.01 g C}}{\text{44.01 g }\text{CO}_{2}}= \text{1.400 g C}$

(b) Mass of H

$\text{Mass of H} = \text{2.10 g H$_{2}$O}\times \dfrac{\text{2.016 g H}}{\text{18.02 g H$_{2}$O}} = \text{0.2349 g H}$

(c) Mass of O

Mass of O = 3.5 - 1.400 - 0.2349 = 1.87 g

2. Calculate the moles of each element

$\text{Moles of C = 1400 mg C}\times\dfrac{\text{1 mmol C}}{\text{12.01 mg C }} = \text{116.6 mmol C}\\\\\text{Moles of H = 234.9 mg H} \times \dfrac{\text{1 mmol H}}{\text{1.008 mg H}} = \text{233.1 mmol H}\\\\\text{Moles of O = 1870 mg O} \times \dfrac{\text{1 mmol O}}{\text{16.00 mg O}} = \text{116 mmol O}$

3. Calculate the molar ratios

Divide all moles by the smallest number of moles.

$\text{C: } \dfrac{116.6}{116.6}= 1\\\\\text{H: } \dfrac{233.1}{116.6} = 1.999\\\\\text{O: } \dfrac{116}{116.6} = 1.00$

4. Round the ratios to the nearest integer

C:H:O = 1:2:1

5. Write the empirical formula

The empirical formula is CH₂O.

6. Calculate the molecular formula.

EF Mass = (12.01 + 2.016 + 16.00) u = 30.03 u

The molecular formula is an integral multiple of the empirical formula.

MF = (EF)ₙ

$n = \dfrac{\text{MF Mass}}{\text{EF Mass }} = \dfrac{\text{150 u}}{\text{30.03 u}} = 5.00 \approx 5$

MF = (CH₂O)₅ = C₅H₁₀O₅

The molecular formula of X is C₅H₁₀O₅.

8 0

3 years ago

Which one of the following is different from the others A .HCl B. HF C. HBr D. HI

lora16 [44]

Answer:

D.HI

Explanation:

because this is the most different

5 0

2 years ago

Which atom or ion is the largest? A. K B. K+ C. Ca D. Ca2+ E. Li

pishuonlain [190]

Answer:

A. K

Step-by-step explanation:

Remember the trends in the Periodic Table:

Atomic radii decrease from left to right across a Period.
Atomic radii increase from top to bottom in a Group.
Ionic radii of metal cations are smaller than those of their atoms.

Thus, the largest atoms are in the lower left corner of the Periodic Table.

The diagram below shows that K is closest to the lower left, so it is the largest atom. It is also larger than any of the cations.

5 0

3 years ago

What is the difference between corrosion and rusting

BartSMP [9]

Answer:

Corrosion is the process of deterioration of materials as a result of chemical, electrochemical or other reactions. Rusting is a part of corrosion and is a chemical process which results in the formation of red or orange coating on the surface of metals. ... Rust or rusting can affect only iron and its alloys.

Explanation:

4 0

2 years ago

Due Tuesday 09-07-2021 Please help immediately!! I have 10 missing assignments from being absent

jeka57 [31]

Answer:

Go to

On the left, click Missing.

(Optional) To review more details, click an item. View details.

Explanation:

7 0

2 years ago

Read 2 more answers