Sodium hydroxide, naoh, is a strong base that is used in industrial synthesis and processes such as making paper. what is the mass of 2.80 ×1022 molecules of naoh (molar mass = 40.0 g/mol)?

### Answers

1.86 g

Explanation:

We must convert formula units of NaOH to moles and then to mass of NaOH.

Step 1. Convert molecules to moles

Step 2. Convert moles to grams

Mass of molecules of NaOH = 1.86 g

Explanation:

Avogadro’s number represent the number of the constituent particles which are present in one mole of the substance. It is named after scientist Amedeo Avogadro and is denoted by .

Avogadro constant:-

So,

molecules of NaOH are present in 1 mole of NaOH

Given, Molar mass of NaOH = 40.0 g/mol

This means, mass of 1 mole of NaOH = 40 g

So,

molecules of NaOH weighs 40 g

1 molecule of NaOH weighs g

molecules of NaOH weighs g

Mass of molecules of NaOH = 1.86 g

Mass of NaOH = 1.594 g

Solution:

Data Given:

Number of Molecules = 2.40 × 10²²

M.Mass of NaOH = 40.0 g.mol⁻¹

Mass of NaOH = ?

Step 1: Calculate Moles of NaOH;

Moles = Number of Molecules ÷ 6.022 × 10²³ Molecules.mol⁻¹

Putting value,

Moles = 2.40 × 10²² Molecules ÷ 6.022 × 10²³ Molecules.mol⁻¹

Moles = 0.04 mol

Step 2: Calculate Mass of NaOH;

Moles = Mass ÷ M.Mass

Solving for Mass,

Mass = Moles × M.Mass

Putting values,

Mass = 0.04 mol × 40.0 g.mol⁻¹

Mass = 1.594 g

1.46 g

Explanation:

For this exercise we need the Avogadro’s number that represents the number of molecules that has a mole of a substance and is value is 6.022x10^23. That is to say that 1 mole of NAOH has 6.022x10^23 molecules and by a rule of three we have:

1 mole NaOH ----------- 6.022x10^23 molecules

X ----------- 2.20x10^22 molecules

X = 0.0365 moles NaOH

Then, 2.20x10^22 molecules of NaOH represent 0.0365 moles of NaOH.

To find the mass we use another rule of three with the NaOH molar mass:

1 mole NaOH ------ 40.0 g

0.0365 moles NaOH ------ X

X= 1.46 g

So, 0.0365 moles of NaOH have a mass of 1.46 g or 2.20 ×10^22 molecules of NaOH have a mass of 1.46 g

1.792 g

Explanation:

We are given;

Formula units of NaOH as 2.70 ×10^22 Molar mass of NaOH as 40.0 g/mol

We are required to determine the mass of NaOH in the given formula units;

Step 1: Determine the number of moles of NaOHWe need to know that 1 mole of a compound contains formula units equivalent to the Avogadro's number, 6.022 × 10^23.Therefore;

1 mole of NaOH = 6.022 × 10^23 formula units

Thus;

Moles of NaOH = 2.70 ×10^22 ÷ 6.022 × 10^23 formula units/mol

= 0.0448 moles

Step 2: Determine the mass of NaOH

Moles = mass ÷ Molar mass

Therefore,

Mass = Moles × Molar mass

= 0.0448 moles × 40.0 g/mol

= 1.792 g

Thus, the mass of 2.70 × 10^22 formula units of NaOH is 1.792 g

1.926 g of NaOH

Explanation:

Concept tested: Mole and Avogadro's number

We need to know that , 1 mole of a compound contains number of molecules equivalent to the Avogadro's number.Th Avogadro's number is 6.022 × 10^23

Therefore;

1 mole of a compound = 6.022 × 10^23 molecules

In this case; Our compound is NaOH

Therefore;

1 mole of NaOH contains 6.022 × 10^23 molecules

But; Molar mass of NaOH is 40.0 g/mol

Therefore;

40.0 g of NaOH contains 6.022 × 10^23 molecules

With this we can calculate the mass of 2.90 × 10^22 molecules

Mass of a compound = (number of molecules ÷ Avogadro's constant) × molar mass

Therefore;

Mass of NaOH =(2.90 × 10^22 molecules ÷ 6.022 × 10^23 molecules)40g

= 1.9263 g

= 1.926 g NaOH

Thus, the mass of NaOH is 1.926 g

a. 3,6x10⁻⁴ moles

b. 1,096M

c. 1,53 g of NaOH

Explanation:

a. Theobromine has a molar mass of:

C: 12,01×7= 84,07 g/mol

H: 1,01×8= 8,08 g/mol

N: 14×4= 56,04 g/mol

O: 16×2= 32 g/mol

84,07 g/mol + 8,08 g/mol + 56 g/mol + 32 g/mol = 180,15g/mol. Thus, in 0,064g of theobromine are:

= 3,6x10⁻⁴ moles -two significant figures-

b. Molar mass of H₂SO₄ is 98,079 g/mol.

151,1g are:

= 1,54 moles of H₂SO₄

As molarity is moles of solute per liters of solution, molarity is:

1,54 moles of H₂SO₄ / 1,405L = 1,096 M

c. 2,30x10²² molecules of NaOH are:

2,30x10²²molecules × (1mol/6,022x10²³molecules) = 0,0382 moles of NaOH

As molar mass of NaOH is 40,04g/mol:

= 1,53 g of NaOH

I hope it helps!

Explanation : We have got molecules of NaOH,

so we get,

g of NaOH/mol

On solving we get, answer as 1.859 g

Hence the g of NaOH will be 1.86.

In NaOH - there are 6.022 x 10²³ NaOH molecules in 1 mol of NaOH

Mass of 1 mol of NaOH - 40 g

therefore 6.022 x 10²³ molecules weigh - 40 g

Then 2.60 x 10²² molecules - 40 x 2.60 x 10²² / (6.022 x 10²³ )

mass is then - 1.73 g

40.0 g 6.02x10²³ molecules

?? g 2.40x10²² molecules

2.40x10²² x ( 40.0 ) / 6.02x10²³ =

9.6x10²³ / 6.02x10²³ => 1.594 g

hope this helps!