All categories

3 years ago

A scientist has 207.45g of H2O in a beaker. How many water molecules are in the beaker?

Chemistry

1 answer:

Tasya [4]3 years ago

4 0

Answer:

6.94 x 10²⁴molecules

Explanation:

Given parameters:

Mass of water = 207.45g

Unknown:

Number of molecules = ?

Solution:

To solve this problem, we must understand:

1 mole of a substance contains 6.02 x 10²³ molecules

Now, first find the number of moles of water;

Number of moles = $\frac{mass}{molar mass}$

Molar mass of water = 2(1) + 16 = 18g/mol

Number of moles = $\frac{207.45}{18}$ = 11.53moles

So;

1 mole of a substance contains 6.02 x 10²³ molecules

11.53moles of carbon dioxide will contain 11.53 x 6.02 x 10²³

= 6.94 x 10²⁴molecules

You might be interested in

calculate the mass of calcium phosphate and the mass of sodium chloride that could be formed when a solution containing 12.00g o

Leviafan [203]

Answer : The mass of calcium phosphate and the mass of sodium chloride that formed could be, 9.3 and 10.5 grams respectively.

Explanation : Given,

Mass of $Na_3PO_4$ = 12.00 g

Mass of $CaCl_2$ = 10.0 g

Molar mass of $Na_3PO_4$ = 164 g/mol

Molar mass of $CaCl_2$ = 111 g/mol

Molar mass of $NaCl$ = 58.5 g/mol

Molar mass of $Ca_3(PO_4)_2$ = 310 g/mol

First we have to calculate the moles of $Na_3PO_4$ and $CaCl_2$ .

$\text{Moles of }Na_3PO_4=\frac{\text{Given mass }Na_3PO_4}{\text{Molar mass }Na_3PO_4}$

$\text{Moles of }Na_3PO_4=\frac{12.00g}{164g/mol}=0.0732mol$

and,

$\text{Moles of }CaCl_2=\frac{\text{Given mass }CaCl_2}{\text{Molar mass }CaCl_2}$

$\text{Moles of }CaCl_2=\frac{10.0g}{111g/mol}=0.0901mol$

Now we have to calculate the limiting and excess reagent.

The balanced chemical reaction is:

$2Na_3PO_4+3CaCl_2\rightarrow 6NaCl+Ca_3(PO_4)_2$

From the balanced reaction we conclude that

As, 3 mole of $CaCl_2$ react with 2 mole of $Na_3PO_4$

So, 0.0901 moles of $CaCl_2$ react with $\frac{2}{3}\times 0.0901=0.0601$ moles of $Na_3PO_4$

From this we conclude that, $Na_3PO_4$ is an excess reagent because the given moles are greater than the required moles and $CaCl_2$ is a limiting reagent and it limits the formation of product.

Now we have to calculate the moles of $NaCl$ and $Ca_3(PO_4)_2$

From the reaction, we conclude that

As, 3 mole of $CaCl_2$ react to give 6 mole of $NaCl$

So, 0.0901 mole of $CaCl_2$ react to give $\frac{6}{3}\times 0.0901=0.1802$ mole of $NaCl$

and,

As, 3 mole of $CaCl_2$ react to give 1 mole of $Ca_3(PO_4)_2$

So, 0.0901 mole of $CaCl_2$ react to give $\frac{1}{3}\times 0.0901=0.030$ mole of $Ca_3(PO_4)_2$

Now we have to calculate the mass of $NaCl$ and $Ca_3(PO_4)_2$

$\text{ Mass of }NaCl=\text{ Moles of }NaCl\times \text{ Molar mass of }NaCl$

$\text{ Mass of }NaCl=(0.1802moles)\times (58.5g/mole)=10.5g$

and,

$\text{ Mass of }Ca_3(PO_4)_2=\text{ Moles of }Ca_3(PO_4)_2\times \text{ Molar mass of }Ca_3(PO_4)_2$

$\text{ Mass of }Ca_3(PO_4)_2=(0.030moles)\times (310g/mole)=9.3g$

Therefore, the mass of calcium phosphate and the mass of sodium chloride that formed could be, 9.3 and 10.5 grams respectively.

5 0

3 years ago

Which of the following statements is true about both nuclear fusion and nuclear fission?

creativ13 [48]

The correct answer is A.

B is incorrect because that only applies to nuclear fission.

C is incorrect because it only applies to nuclear fusion.

D is incorrect because energy can be neither created nor destroyed meaning that this statement is physically impossible,

8 0

3 years ago

Read 2 more answers

How many hydrogen atoms are in 4.40 mol of ammonium sulfide

katrin2010 [14]

The number of hydrogen atoms that are in 4.40 mol of ammonium sulfide is 2.12 x10^25 atoms

calculation
find the number of moles of Hydrogen in ammonium sulfide (NH4)2S

that is 4.40 x number of hydrogen atoms in (NH4)2S ( 4x2= 8 atoms)

moles is therefore= 4.40 x8= 35.2 moles

by use of Avogadro's law constant

that is 1mole = 6.02 x10^23 atoms
35.2 moles=?

by cross multiplication
{35.2 moles x 6.02 x10^23} /1 mole = 2.12 x10^25 atoms

5 0

3 years ago

Read 2 more answers

Balanced equation for the neutralization of these 2. HCl , Ca(OH)2

Ghella [55]

Balanced equation:

2 HCl + 1 Ca(OH)₂ = 1 CaCl₂ + 2 H₂O

hope this helps!

5 0

3 years ago

Read 2 more answers

Plz help I’ll mark brainliest

Neko [114]

Answer:

Industrialization has historically led to urbanization by creating economic growth and job opportunities that draw people to cities. Urbanization typically begins when a factory or multiple factories are established within a region, thus creating a high demand for factory labor.

4 0

3 years ago

Read 2 more answers