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1 year ago

How many moles are in 8.30x10^23 molecules of H2o

Chemistry

2 answers:

sasho [114]1 year ago

8 0

Answer: 1.38 moles

Explanation: According to Avogadro's law, 1 mole of every substance contains Avogadro number of particles (atoms, molecules or ions) i.e. $6.023\times 10^{23}$ particles.

Given : 1 mole molecule of water contains $6.023\times 10^{23}$ molecules of water.

$6.023\times 10^{23}$ molecules are present in = 1 mole

$8.30\times 10^{23}$ molecules will be present in = $\frac{1}{6.023\times 10^{23}}\times 8.30\times 10^{23}=1.38 moles$

Thus $8.30\times 10^{23}$ molecules is equal to 1.38 moles.

LUCKY_DIMON [66]1 year ago

4 0

You multiply avogadro's number to what you were given.
8.30x10^23 * 6. 0221409x10^23
=1.357*10^25

That should be the right answer but I'm not sure. It has been awhile since I have done this.

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I NEED HELP ASAP, WILL MARK BRAINLEST!

Andre45 [30]

Answer:

1. 90%

2. 217.4 g O₂

3. 95.0%

4. Trial 2 ratios

Explanation:

Original: SiCl₄ + O₂ → SiO₂ + Cl₂

Balanced: SiCl₄ + O₂ → SiO₂ + 2Cl₂

Trial SiCl₄ O₂ SiO₂

1 120 g 240 g 38.2 g

2 75 g 50 g 25.2 g

Percentage yield for trial 1

We need to get actual yield (38.2 g) and theoretical yield, in grams.

Mass to moles:

molar mass SiCl₄: 28.09 + 4(35.45) = 169.9 g/mol

120 g SiCl₄ x 1 mol/169.9 g = .706 mol SiCl₄

Moles to moles:

For each mole SiCl₄, we have one mol SiO₂ based on the balanced rxn.

.706 mol SiCl₄ = .706 mol SiO₂

Moles to mass:

molar mass SiO₂: 28.09 + 2(16.00) = 60.09 g/mol

.706 mol SiO₂ x 60.09g/mol = 42.44 g SiO₂

Theoretical yield:

actual/theoretical x 100

38.2 / 42.44 = .900 = 90.0% yield

Leftover reactant for trial 1

We know oxygen is the excess reactant.

Mass to moles:

molar mass O₂ = 32.00 g/mol

240 g O₂ x 1 mol/32.00 g = 7.5 mol O₂

We used .706 mol SiO₂, so we also used .706 mol O₂.

7.5 - .706 = 6.8 moles left over

Moles to mass:

6.8 mol O₂ x 32.00g/mol = 217.4 g O₂

Percentage yield for trial 2

Mass to moles:

molar mass SiCl₄: 169.9 g/mol

75 g SiCl₄ x 1 mol/169.9 g = .441 mol SiCl₄

Moles to moles:

For each mole SiCl₄, we have one mol SiO₂ based on the balanced rxn.

.441 mol SiCl₄ = .441 mol SiO₂

Moles to mass:

molar mass SiO₂: 60.09 g/mol

.441 mol SiO₂ x 60.09g/mol = 26.5 g SiO₂

Theoretical yield:

actual/theoretical x 100

25.2 / 26.5 = .950 = 95.0% yield

Because the percentage yield of trial 2 is higher than that of trial 1, we know that the ratio of reactants in trial 2 is more efficient! We got a result closer to our theoretical yield.

6 0

2 years ago

At 4.00 L, an expandable vessel contains 0.864 mol of oxygen gas. How many liters of oxygen gas must be added at constant temper

fgiga [73]

Answer:

We have to add 2.30 L of oxygen gas

Explanation:

Step 1: Data given

Initial volume = 4.00 L

Number of moles oxygen gas= 0.864 moles

Temperature = constant

Number of moles of oxygen gas increased to 1.36 moles

Step 2: Calculate new volume

V1/n1 = V2/n2

⇒V1 = the initial volume of the vessel = 4.00 L

⇒n1 = the initial number of moles oxygen gas = 0.864 moles

⇒V2 = the nex volume of the vessel

⇒n2 = the increased number of moles oxygen gas = 1.36 moles

4.00L / 0.864 moles = V2 / 1.36 moles

V2 = 6.30 L

The new volume is 6.30 L

Step 3: Calculate the amount of oxygen gas we have to add

6.30 - 4.00 = 2.30 L

We have to add 2.30 L of oxygen gas

4 0

2 years ago

The graph shows the gravitational potential energy of a radio controlled toy helicopter.describe the motion of the toy

ICE Princess25 [194]

Gravitational potential energy is observed when an object is not in rest or is in motion. In this case, the helicopter is in motion where the direction is going upward with a negative potential energy. Thank you for your question. Please don't hesitate to ask in Brainly your queries.

6 0

2 years ago

the image above shows a chamber with a fixed volume filled with gas at a pressure of 1560 mmHg and a temperature of 445.0 K. If

Sedaia [141]

Answer:

The new pressure of the gas in the chamber is 1,093.75 mmHg

Explanation:

The Gay-Lussac Law is a gas law that relates pressure and temperature to constant volume. This law says that the pressure of the gas is directly proportional to its temperature.

That is, if the temperature increases, the pressure increases, while if the temperature decreases, the pressure decreases. So the Gay-Lussac law can be expressed mathematically as follows:

$\frac{P}{T} =k$

Having an initial and an end state of a gas, the following expression can be used:

$\frac{P1}{T1} =\frac{P2}{T2}$

In this case:

P1= 1560 mmHg
T1= 445 K
P2=?
T2= 312 K

Replacing:

$\frac{1560 mmHg}{445 K} =\frac{P2}{312 K}$

Solving:

$P2=\frac{1560 mmHg}{445 K} *312K$

P2=1,093.75 mmHg

The new pressure of the gas in the chamber is 1,093.75 mmHg

7 0

1 year ago

in a mixture of helium and chlorine, occupying a volume of 12.8 l at 605.6 mmhg and 21.6 oc, it is found that the partial pressu

rodikova [14]

Answer:

Mass of sample = 8.483 g

Explanation:

Given data;

Volume of mixture = 12.8 L

Pressure = 605.6 mmHg ( 605.6 / 760 = 0.797 atm)

Temperature = 21.6 °C (21.6 + 271.15 = 294.8 K)

Partial pressure of chlorine = 143 mmHg ( 143/760 = 0.19 atm)

Solution:

First of all we will determine the number of moles of mixture.

PV = nRT

n = PV/RT

n = 0.797atm × 12.8L / 0.0821 atm. dm³ mol⁻¹ K⁻¹ ×294.8 K

n = 10.202 / 24.2031

n = 0.422 mol

partial pressure of chlorine is 0.19 atm so mole fraction is,

mole fraction = 0.19/0.797

mole fraction = 0.24

moles of chlorine = 0.24 × 0.422 = 0.1013 mol

moles of helium = moles of mixture - moles of chlorine

moles of helium = 0.422 - 0.1013

moles of helium = 0.3207 mol

Mass of chlorine = moles × molar mass

Mass of chlorine = 0.1013 mol × 71 g/mol

Mass of chlorine = 7.2 g

Mass of helium = moles × molar mass

Mass of helium = 0.3207 mol × 4 g/mol

Mass of helium = 1.283 g

Mass of sample = mass of chlorine + mass of helium

Mass of sample = 7.2 g + 1.283 g

Mass of sample = 8.483 g

5 0

1 year ago