1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
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

You might be interested in
Write Huckel's rule below and determine how many electrons are required to make an aromatic ring with n = 0, 1, and 2.
lisov135 [29]

<u>Answer:</u> The number of electrons for n = 0, 1 and 2 are 2, 6 and 10 respectively.

<u>Explanation:</u>

Huckel's rule is used to determine the aromaticity in a compound. The number of delocalized \pi- electrons are calculated by using the equation:

\text{Number of delocalized }\pi-\text{ electrons}=4n+2

where,

n = 0 or any whole number

  • Calculating the value of electrons for n = 0

Putting values in above equation, we get:

\text{Number of delocalized }\pi-\text{ electrons}=4(0)+2=2

  • Calculating the value of electrons for n = 1

Putting values in above equation, we get:

\text{Number of delocalized }\pi-\text{ electrons}=4(1)+2=6

  • Calculating the value of electrons for n = 2

Putting values in above equation, we get:

\text{Number of delocalized }\pi-\text{ electrons}=4(2)+2=10

Hence, the number of electrons for n = 0, 1 and 2 are 2, 6 and 10 respectively.

4 0
3 years ago
1. A substance, A₂B, has the composition by mass of 60% A and 40% B. What is the composition of AB₂ by mass?
Lubov Fominskaja [6]
This may help you
Use an arbitrary mass, 100 g is an easy number to work with. 60% of 100 g is 60 g, there are two A's. Each A is 30 g 40 g is B, and there is only one, so B is 40 g. <span>A<span>B2</span></span>, would have a mass of 30 g + 2*40 g = 110 g The new percent by mass composition of A is: <span><span><span>30g</span><span>110g</span></span>∗100%=27.3%</span> The new percent by mass composition of B is: <span><span><span><span>80g</span><span>110g</span></span>∗100%=72.7%</span></span>
8 0
3 years ago
EASY 100 POINTS, WILL MARK BRAINLEST, 2 QUESTIONS, SHOW YOUR WORK OR NO POINTS
SVETLANKA909090 [29]

Answer:

Explanation:

1. Please provide the enthalpy info - I will work on it with the info

2.

i) Reaction a should be modified to match the number of S in equation:

 2S + 2O2 -> 2SO2     deltaH = -370kJ

ii) Reaction b should be written reversely to match the reactants of SO2:

 2SO2 + O2 -> 2SO3     deltaH = 256kJ

iii) Adding the equations together:

 2S + 3O2 -> 2SO3

iv) Enthalpy of the combined reaction = -370+256 = -114kJ

 It is negative so the reaction is exothermic.

5 0
3 years ago
Read 2 more answers
Technetium (Tc; Z = 43) is a synthetic element used as a radioactive tracer in medical studies. A Tc atom emits a beta particle
Sedaia [141]

Question in incomplete, complete question is:

Technetium (Tc; Z = 43) is a synthetic element used as a radioactive tracer in medical studies. A Tc atom emits a beta particle (electron) with a kinetic energy (Ek) of 4.71\times 10^{-15}J . What is the de Broglie wavelength of this electron (Ek = ½mv²)?

Answer:

6.762\times 10^{-12} m is the de Broglie wavelength of this electron.

Explanation:

To calculate the wavelength of a particle, we use the equation given by De-Broglie's wavelength, which is:

\lambda=\frac{h}{\sqrt{2mE_k}}

where,

= De-Broglie's wavelength = ?

h = Planck's constant = 6.624\times 10^{-34}Js

m = mass of beta particle = 9.1094\times 10^{-31} kg

E_k = kinetic energy of the particle = 4.71\times 10^{-15}J

Putting values in above equation, we get:

\lambda =\frac{6.624\times 10^{-34}Js}{\sqrt{2\times 9.1094\times 10^{-31} kg\times 4.71\times 10^{-15}J}}

\lambda = 6.762\times 10^{-12} m

6.762\times 10^{-12} m is the de Broglie wavelength of this electron.

3 0
3 years ago
HURRY!!<br><br><br><br><br><br><br><br><br><br><br> I NEEE HELP!!!
Ludmilka [50]

Answer:

NEEE

Explanation:

5 0
3 years ago
Other questions:
  • How can you increase the boiling point of water?
    8·1 answer
  • How is the empirical formula of copper chloride hydrate found?
    13·1 answer
  • How is matter conserved in the carbon cycle?
    10·2 answers
  • Violet light has a frequency of 7.26 * 1014 Hz and travels at a speed of 3.00 * 108 m/s.
    7·2 answers
  • The Constitution gives which of the following powers to the Vice President?
    11·2 answers
  • What is the name of this hydrocarbon?
    8·2 answers
  • ༒How much does the earth weigh?☆☆☆☆☆☆☆☆☆☆☆☆​
    5·1 answer
  • What's the agriculture​
    7·2 answers
  • Consider the molecular structure for linuron, an herbicide, provided in the questions below. How many pi bonds are in the molecu
    8·1 answer
  • some regions of a polypeptide may coil or fold back on themselves. this is called , and the coils or folds are held in place by
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!