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3 years ago

How many atoms are in 3.5 grams of copper

Chemistry

2 answers:

storchak [24]3 years ago

7 0

Avegadro's number = 6.02 x10^23 atoms
so
3.5g x 1mol/63.55g Cu x 6.02 x 10^23/ 1mol=3.32 x 10^22 atoms

slega [8]3 years ago

5 0

<u>Answer:</u> For the given mass of copper, the number of atoms are $3.3121\times 10^{22}$

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Given mass of copper = 3.5 g

Molar mass of copper = 63.55 g/mol

Putting values in above equation, we get:

$\text{Moles of copper}=\frac{3.5g}{63.55g/mol}=0.055mol$

According to mole concept:

1 mole of an element contains $6.022\times 10^{23}$ number of atoms

So, 0.055 moles of copper will contain = $0.055\times 6.022\times 10^{23}=3.3121\times 10^{22}$ number of atoms.

Hence, for the given mass of copper, the number of atoms are $3.3121\times 10^{22}$

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The atmospheric pressure on the surface of Venus is 6.84X10^4. Calculate the atmospheric pressure in atm and torr. Round each of

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Answer:

0.675 atm

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Given is that, the atmospheric pressure on the surface of Venus is

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To convert divide the pressure value by 101325.

Pressure in atm = $\frac{6.84 \times 10^{4} }{101325}$

= 0.675055 atm

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3 years ago

A sample of carbon dioxide occupies a 5.13 dm3 container at STP. What is the volume of the gas at a pressure of 286.5 kPa and a

suter [353]

Considering the ideal gas law and STP conditions, the volume of the gas at a pressure of 286.5 kPa and a temperature of 12.9°C is 1.8987 L.

<h3>Definition of STP condition</h3>

The STP conditions refer to the standard temperature and pressure. Pressure values at 1 atmosphere and temperature at 0 ° C are used and are reference values for gases. And in these conditions 1 mole of any gas occupies an approximate volume of 22.4 liters.

<h3>Ideal gas law</h3>

Ideal gases are a simplification of real gases that is done to study them more easily. It is considered to be formed by point particles, do not interact with each other and move randomly. It is also considered that the molecules of an ideal gas, in themselves, do not occupy any volume.

The pressure, P, the temperature, T, and the volume, V, of an ideal gas, are related by a simple formula called the ideal gas law:

P×V = n×R×T

where:

P is the gas pressure.
V is the volume that occupies.
T is its temperature.
R is the ideal gas constant. The universal constant of ideal gases R has the same value for all gaseous substances.
n is the number of moles of the gas.

<h3>Volume of gas</h3>

In first place, you can apply the following rule of three: if by definition of STP conditions 22.4 L are occupied by 1 mole of carbon dioxide, 5.13 L (5.13 dm³= 5.13 L, being 1 dm³= 1 L) are occupied by how many moles of carbon dioxide?

$amount of moles of carbon dioxide=\frac{5.13 Lx1 mole of carbon dioxide}{22.4 L}$