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Roman55 [17]
2 years ago
14

How mant grams are there in 7.15 x 10^24 molecules of water?

Chemistry
2 answers:
AysviL [449]2 years ago
8 0

Answer:

\boxed {\boxed {\sf B. \ 214 \ g }}

Explanation:

We are asked to find the mass of a given number of water (H₂O) molecules.

<h3>1. Convert Molecules to Moles</h3>

First, we convert molecules to moles. We will use Avogadro's Number or 6.022 × 10²³. This is the number of particles (atoms, molecules, formula units, etc.) in 1 mole of a substance. In this case, the particles are molecules of water. Therefore,<u> there are 6.022 ×10²³ molecules of water in 1 mole of water</u>.

We will convert using dimensional analysis, so we must set up a ratio using the underlined information.

\frac {6.022 \times 10^{23} \ molecules \ H_2O}{1 \ mol \ H_2O}

We are converting 7.15 × 10²⁴ molecules of water to moles, so we multiply the ratio by that value.

7.15 \times 10^{24} \ molecules \ H_2O*\frac {6.022 \times 10^{23} \ molecules \ H_2O}{1 \ mol \ H_2O}

Flip the ratio so the units of molecules of water cancel each other out.

7.15 \times 10^{24} \ molecules \ H_2O*\frac {1 \ mol \ H_2O} {6.022 \times 10^{23} \ molecules \ H_2O}

7.15 \times 10^{24} *\frac {1 \ mol \ H_2O} {6.022 \times 10^{23} }

\frac {7.15 \times 10^{24}} {6.022 \times 10^{23} } \ mol \ H_2O

11.87313185\ mol \ H_2O

<h3>2. Convert Moles to Grams </h3>

Next, we convert moles to grams. We will use the molar mass. This is the mass of 1 mole of a substance. These values are found on the Periodic Table. They are equivalent to the atomic masses, but the units are grams per mole instead of atomic mass units.

Look up the molar masses of the individual elements in water: hydrogen and oxygen.

  • H: 1.008 g/mol
  • O: 15.999 g/mol

There is a subscript of 2 after H, so there 2 moles of hydrogen in 1 mole of water. Multiply the molar mass by 2 before adding oxygen's molar mass.

  • H₂: 1.008 * 2 = 2.016 g/mol
  • H₂O: 2.016 + 15.999 = 18.015 g/mol

We convert using dimensional analysis again and set up another ratio.

\frac {18.015 \ g \ H_2O}{ 1 \ mol \ H_2O}

Multiply by the number of moles we just calculated.

11.87313185 \ mol \ H_2O *\frac {18.015 \ g \ H_2O}{ 1 \ mol \ H_2O}

The units of moles of water cancel.

11.87313185  *\frac {18.015 \ g \ H_2O}{ 1 }

213.8944703 \ g \ H_2O

The original measurement of molecules has 3 significant figures, so our answer must have the same. For the number we found, that is the one place. The 8 in the tenths place tells us to round the 3 up to a 4.

214 \ g \ H_2O

There are approximately <u>214 grams of water</u> and <u>choice B</u> is correct.

worty [1.4K]2 years ago
4 0

Answer:

B. 214.02

Explanation:

1 mol of water weighs 18.015 gm and contains 6.023 × 10²³ molecules

From question, We have 7.15 × 10²⁴ molecules

Dividing we get (7.15 × 10 ²⁴) ÷ ( 6.023 × 10²³) = 11.871 molecules

Now, Weight of water = 11.871 × 18.015 = 213.85 which is nearer to option B

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Given the following equation: 4 NH3 (g)5 O2 (g) &gt;4 NO (g) + 6 H20 (I) How many moles of NH3 is required to react with 25.7 gr
Sergeu [11.5K]

Answer:

0.6425 moles of NH_3 is required to react with 25.7 grams of O_2.

Explanation:

mas of oxygen gas = 25.7 g

moles of oxygengas = \frac{25.7 g}{32 g/mol}=0.8031 mol

4NH_3 (g)+5O_2 (g) \rightarrow 4 NO(g) + 6H_20 (I)

According to reaction given above,  5 moles of oxygen gas reacts with 4 moles of ammonia gas.

Then 0.8031 moles of oxygen gas will react with :

\frac{4}{5}\times 0.8031 mol=0.6425 mol of ammonia gas

0.6425 moles of NH_3 is required to react with 25.7 grams of O_2.

5 0
3 years ago
if 26.8g of copper (ll) chloride are dissolved in sufficient water to make 4.00 L of solution, what is the molarity of the solut
artcher [175]

Answer: Molarity of the solution is 4.97 \times 10^{-2} M and water is the solvent.

Explanation:

Given: Mass of solute = 26.8 g

Volume = 4.00 L

Now, moles of copper (II) chloride (molar mass = 134.45 g/mol) are calculated as follows.

No. of moles = \frac{mass}{molar mass}\\= \frac{26.8 g}{134.45 g/mol}\\= 0.199 mol

Molarity is the number of moles of a substance divided by volume of solution in liter.

Therefore, molarity of given solution is calculated as follows.

Molarity = \frac{no. of moles}{Volume (in L)}\\= \frac{0.199 mol}{4.00 L}\\= 0.04975 M\\= 4.97 \times 10^{-2} M

Solvent is defined as a component which is present in higher amount in a solution. Generally, a solvent is present in liquid state but it can also be a solid or gas.

In the given solution, copper (II) chloride is dissolved in water so copper (II) chloride is the solute and water is the solvent.

Thus, we can conclude that molarity of the solution is 4.97 \times 10^{-2} M and water is the solvent.

4 0
3 years ago
What do all substances in the universe have in common?
Dmitry [639]

Answer:

All are made of matter

Explanation:

7 0
3 years ago
A gas bottle contains 8. 61×1023 oxygen molecules at a temperature of 359. 0 k. what is the thermal energy of the gas? (you migh
Cloud [144]

A gas bottle contains 8. 61×1023 oxygen molecules at a temperature of 359. 0 k then the thermal energy of the gas is 6.35KJ.

<h3>What is thermal energy? </h3>

Thermal energy is the energy contained within a system which is responsible for its temperature. Heat is also termed as flow of thermal energy.

Thermal energy is directly proportional to the temperature. As temperature increase thermal energy increases.

Given,

temperature = 395K

Number of oxygen molecules= 8.61 × 10^(23)

Firstly we will calculate the number of moles = N/A

where A is the avagadro number = 6.022 × 10^(23)

number of moles = 8.61 × 10^(23)/6.022 ×10^(23)

number of moles = 1.42moles

Using the energy equation,

E = 3/2 × nRT

where R is the gas constant = 8.314J/molK

E = 3/2 × 1.42 × 8.314 × 359

= 6357.4J

= 6.35KJ

Thus, we found that the thermal energy of the gas is 6.35KJ.

learn more about thermal energy:

brainly.com/question/2409175

#SPJ4

5 0
1 year ago
Calculate the number of moles of O2 gas held in a sealed 2.00 L tank at 3.50 atm and 25 ℃.
Leviafan [203]

Answer:

n=0.286mol

Explanation:

Hello,

In this case, we consider oxygen as an ideal gas, for that reason, we use yhe ideal gas equation to compute the moles based on:

PV=nRT\\\\n=\frac{PV}{RT}

Hence, at 3.50 atm and 25 °C for a volume of 2.00 L we compute the moles considering absolute temperature in Kelvins:

n=\frac{3.50atm*2.00L}{0.082\frac{atm*L}{mol*K}(25+273)K} \\\\n=0.286mol

Best regards.

6 0
3 years ago
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