All categories

3 years ago

2. How many moles are in 8.30 x 1023 molecules of H2O?

Chemistry

1 answer:

daser333 [38]3 years ago

8 0

Answer:

<h2>1.38 moles</h2>

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

$n = \frac{N}{L} \\$

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

$n = \frac{8.30 \times {10}^{23} }{6.02 \times {10}^{23} } = \frac{8.30}{6.02} \\ = 1.3787 37...$

We have the final answer as

<h3>1.38 moles</h3>

Hope this helps you

You might be interested in

Explain how you find the instantaneous speed or velocity of an object

puteri [66]

Answer:

divide the distance by the average

Explanation:

ash QC ok

3 0

3 years ago

20. What volume of 0.350M KMnO4 solution must be diluted to prepare 600. mL of

Dafna1 [17]

Answer:

25.7 mL

Explanation:

Step 1: Given data

Initial volume (V₁): ?

Initial concentration (C₁): 0.350 M

Final volume (V₂): 600 mL

Final concentration (C₂): 0.150 M

Step 2: Calculate the volume of the initial solution

We have a concentrated solution and we want to prepare a diluted one. We can calculate the initial volume using the dilution rule.

C₁ × V₁ = C₂ × V₂

V₁ = C₂ × V₂ / C₁

V₁ = 0.150 M × 600 mL / 0.350 M

V₁ = 25.7 mL

3 0

3 years ago

The unit used to measure barometric or air pressure

Bumek [7]

Answer:

A barometer is an instrument used to measure air pressure and track weather systems. The most common unit of measurement used in barometers is the millibar (mb).

Explanation:

7 0

3 years ago

450g of chromium (III) sulfate reacts with excess potassium phosphate. How many grams of potassium sulfate will be produced? (AN

Oduvanchick [21]

Answer:

599.26 grams of potassium sulfate will be produced.

Explanation:

$Cr_2(SO_4)_3(aq)+2K_3PO_4(aq)\rightarrow 2CrPO_4(s)+3K_2SO_4(aq)$

Moles of chromium (III) sulfate = $\frac{450 g}{392 g/mol}=1.1480 mol$

According to reaction, 1 mole of chromium (III) sulfate gives 3 moles of potassium sulfate.

Then 1.1480 moles of chromium (III) sulfate will give:

$\frac{3}{1}\times 1.1480 mol=3.4440 mol$

Mass of 3.4440 moles of potassium sulfate:

= 3.4440 mol × 174 g/mol = 599.26 g

599.26 grams of potassium sulfate will be produced.

8 0

3 years ago

15.00 grams of Chromium react with 15.00 grams of hydrobromic acid. Calculate the theoretical yield of the reaction. At STP what

s2008m [1.1K]

Answer:

(a) 18.03 g

(b) 2.105 L

Step-by-step explanation:

We have the masses of two reactants, so this is a limiting reactant problem.

We know that we will need a balanced equation with masses, moles, and molar masses of the compounds involved.

Step 1. Gather all the information in one place with molar masses above the formulas and masses below them.

M_r: 52.00 80.91 291.71

2Cr + 6HBr ⟶ 2CrBr₃ + 3H₂

Mass/g: 15.00 15.00

Step 2. Calculate the moles of each reactant

Moles of Cr = 15.00 × 1/52.00

Moles of Cr = 0.2885 mol Cr

Moles of HBr = 15.00 × 1/80.91

Moles of HBr = 0.1854 mol HBr ×

Step 3. Identify the limiting reactant

Calculate the moles of CrCl₃ we can obtain from each reactant.

From Cr:

The molar ratio of CrBr₃:Cr is 2 mol CrBr₃:2 mol Cr

Moles of CrBr₃ = 0.2885 × 2/2

Moles of CrBr₃ = 0.2885 mol CrCl₃

From HBr:

The molar ratio of CrBr₃:HBr is 2 mol CrBr₃:6 mol HBr.

Moles of CrBr₃ = 0.1854 × 2/6

Moles of CrBr₃ = 0.061 80 mol CrBr₃

The limiting reactant is HBr because it gives the smaller amount of CrBr₃.

Step 4. Calculate the theoretical yields of CrBr₃ and H₂.

Theoretical yield of CrBr₃ = 0.061 80 × 291.71/1

Theoretical yield of CrBr₃ = 18.03 g CrCl₃

The molar ratio is 3 mol H₂:6 mol HBr

Theoretical yield of H₂ = 0.1854 × 3/6

Theoretical yield of H₂ = 0.092 70 mol H₂

Step 5. Calculate the volume of H₂ at STP

STP is 1 bar and 0 °C.

The molar volume of a gas at STP is 22.71 L.

Volume = 0.092 70 × 22.71/1

Volume = 2.105 L

Step 6. Calculate the percent yield

% Yield = actual yield/theoretical yield × 100 %

Actual yield = 15.35 g

% yield = 15.35/18.03 × 100

% yield = 85.15 %

8 0

3 years ago