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2 years ago

Calculate the number of Li atoms in 7.8 mol of Li.

Chemistry

1 answer:

Gwar [14]2 years ago

6 0

<h3>Answer:</h3>

4.7 × 10²⁴ atoms Li

<h3>General Formulas and Concepts:</h3>

Math

Pre-Algebra

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

Chemistry

Atomic Structure

Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.

Stoichiometry

Using Dimensional Analysis

<h3>Explanation:</h3>

Step 1: Define

7.8 mol Li

Step 2: Identify Conversions

Avogadro's Number

Step 3: Convert

Set up: $\displaystyle 7.8 \ mol \ Li(\frac{6.022 \cdot 10^{23} \ atoms \ Li}{1 \ mol \ Li})$
Multiply/Divide: $\displaystyle 4.69716 \cdot 10^{24} \ atoms \ Li$

Step 4: Check

We are told to round to 2 sig figs. Follow sig fig rules and round.

4.69716 × 10²⁴ atoms Li ≈ 4.7 × 10²⁴ atoms Li

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Dahasolnce [82]

Answer:

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Explanation:

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6 0

2 years ago

How many sulfur atoms are there in 3.90 mol of sulfur?

Ilya [14]

In a mole of anything, there are 6.023 x 10^23 units. So, in 3.9 moles of sulfur, there are 3.9 * 6.023 x 10^23 = 23 x 10^23 = 2.3 x 10^24 atoms (keeping only 2 sig figs). Hope I help!!

6 0

3 years ago

An enclosed vessel contains 2.5g of 9b nitrogen and 13.3g of chlorine at s.T.P. Of What will be the partial pressure of the Il n

kow [346]

Answer:

0.535 atm

Explanation:

Since the volume of the tank is constant, we use Gay- Lussac's law to find the pressure at 180°C.

So, P₁/T₁ = P₂/T₂ where P₁ = pressure at S.T.P = 1 atm, T₁ = temperature at S.T.P = 273.15 K, P₂ = pressure of gas at 180 °C and T₂ = 180 °C = 273.15 + 180 K = 453.15 K

So, P₁/T₁ = P₂/T₂

P₂ = P₁T₂/T₁

Substituting the values of the variables into the equation, we have

P₂ = P₁T₂/T₁

P₂ = 1 atm × 453.15 K/273.15 K

P₂ = 1 atm × 1.66

P₂ = 1.66 atm

We now need to find the total number of moles of each gas present

number of moles of nitrogen = mass of nitrogen, m/molar mass of nitrogen molecule M

n = m/M

m = 2.5 g and M = 2 × atomic mass of nitrogen (since it is diatomic) = 2 × 14 g/mol = 28 g/mol

So, n = 2.5 g/28 g/mol

n = 0.089 mol

number of moles of chlorine, n' = mass of chlorine, m'/molar mass of chlorine molecule M'

n' = m'/M'

m' = 13.3 g and M = 2 × atomic mass of chlorine (since it is diatomic) = 2 × 35.5 g/mol = 71 g/mol

So, n' = 13.3 g/71 g/mol

n' = 0.187 mol

So, the total number of moles of gas present is n" = n + n' = 0.089 mol + 0.187 mol = 0.276 mol

So, the partial pressure due to nitrogen gas, P = mole fraction of nitrogen × pressure of gas at 180 °C

P = n/n" × P₂

P = 0.089 mol/0.276 mol × 1.66 atm

P = 0.322 × 1.66 atm

P = 0.535 atm

8 0

3 years ago

The specific shape that an electron moves in inside a sub-level_____

VashaNatasha [74]

Answer:

The specific shape that an electron moves in inside a sub-level shell.

6 0

2 years ago

A 32.8 g sample of gas occupies 22.414 L at STP. What is the molecular weight of this gas?

olasank [31]

Answer:

32.8g/mole

Explanation:

Given parameters:

Mass of sample of gas = 32.8g

Volume = 22.4L

Unknown:

Molecular weight = ?

Solution:

To solve this problem we must understand that at rtp;

1 mole of gas occupies a volume of 22.4L

Number of mole of the gas = 1 mole

Now;

Mass = number of moles x molecular weight

molecular weight = $\frac{mass}{molecular weight}$ = $\frac{32.8g}{1mole }$ = 32.8g/mole

8 0

2 years ago