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2 years ago

How do you determine how many molecules are in a chemical equation

Chemistry

1 answer:

V125BC [204]2 years ago

5 0

Answer:

Determine the mass of substance and it's molar mass. Divide the given mass by it's molar mass to get moles and multiply time

6.002*1023 molecules 1mole

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A volume of 129 mL of hydrogen is collected over water. The water level in the collecting vessel is the same as the outside leve

mixas84 [53]

Explanation:

As it is given that water level is same as outside which means that theoretically, P = 756.0 torr.

So, using ideal gas equation we will calculate the number of moles as follows.

PV = nRT

or, n = $\frac{PV}{RT}$

= $\frac{\frac{756}{760}atm \times 0.129 L}{0.0821 Latm/mol K \times 298 K}$

= 0.0052 mol

Also, No. of moles = $\frac{mass}{\text{molar mass}}$

0.0052 mol = $\frac{mass}{2 g/mol}$

mass = 0.0104 g

As some of the water over which the hydrogen gas has been collected is present in the form of water vapor. Therefore, at $25^{o}C$

$P_{\text{water vapor}}$ = 24 mm Hg

= $\frac{24}{760}$ atm

= 0.03158 atm

Now, P = $\frac{756}{760} - 0.03158$

= 0.963 atm

Hence, n = $\frac{0.963 atm \times 0.129 L}{0.0821 L atm/mol K \times 298 K}$

= 0.0056 mol

So, mass of $H_{2}$ = 0.0056 mol × 2

= 0.01013 g (actual yield)

Therefore, calculate the percentage yield as follows.

Percent yield = $\frac{\text{Actual yield}}{\text{Theoretical yield}} \times 100$

= $\frac{0.01013 g}{0.0104 g} \times 100$

= 97.49%

Thus, we can conclude that the percent yield of hydrogen for the given reaction is 97.49%.

3 0

3 years ago

A sample of copper absorbs 4.31E+1 kJ of heat, resulting in a temperature rise of 6.71E+1 °C. Determine the mass (in kg) of the

olga2289 [7]

Answer: 1.67 kg

Explanation:

The quantity of heat required to raise the temperature of a substance by one degree Celsius is called the specific heat capacity.

$Q=m\times c\times \Delta T$

Q = Heat absorbed= $4.31\times 10^1kJ$ = $43100J$ (1kJ=1000J)

m= mass of substance = ?

c = specific heat capacity = $0.385J/g^0C$

Change in temperature , $\Delta T=T_f-T_i=6.71\times 10^1^0C=67.1^0C$

Putting in the values, we get:

$43100J=m\times 0.385J/g^0C\times 67.1^0C$

$m=1670g=1.67kg$ (1kg=1000g)

Thus the mass (in kg) of the copper sample is 1.67

3 0

3 years ago

If 133mL of a 1.2 M glucose solution is diluted to 41.0L, what is the molarity of the diluted solution?

WITCHER [35]

the formula we is as follows:-

M1V1= M2V2

where

M1=1.2

V1=0.133l

V2=41l

M2=?

1.2 × 0.133 = 41 × M2

0.1596 = 41 × M2

M2 = 0.15960/41

M2 = 0.0038926829

7 0

3 years ago

Which scientist is known as the father of chemistry *?

noname [10]

The correct answer is Antoine-Laurent de Lavoisier. Hope this helps!

3 0

3 years ago

Give 5 examples of each type of mixture. Heterogeneous: Homogeneous:

Kipish [7]

Heterogeneous:
- A salad with tomatoes and almonds
- Salt and Pepper mixed in a bowl (dry)
- A fruit bowl
- Oil and Water
- Solid Tea Herbs and Water
Homogeneous:
- Salt water
- A well blended fruit smoothie
- Lemon water
- Gatorade
- Sprite

5 0

3 years ago

Read 2 more answers