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3 years ago

. What is the mass, in grams, of a sample of 7.83 × 1024 atoms of helium (He)?

Chemistry

1 answer:

erica [24]3 years ago

6 0

Moles He = 7.83 x 10^24 / 6.02 x 10^23 =13.0

<span>mass He = 13.0 mol x 4.00 g/mol = 52.0 g</span>

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What is liquor ammonia fortis?

erik [133]

Answer:

Ammonia fortis liquor is a saturated solution of ammonia in water. It is also called 880 ammonia. Its relative density is 0.880. It is stored in tightly sealed bottles in a cold place. (Sorry if I'm wrong)

Explanation:

6 0

2 years ago

Read 2 more answers

2. Using the following data, calculate the average atomic mass of magnesium (give your answer to the nearest

arlik [135]

Answer:

24.32

Explanation:

From the question given above, the following data were obtained:

Isotope A:

Mass of A = 24

Abundance (A%) = 78.70%

Isotope B

Mass of B = 25

Abundance (B%) = 10.13%

Isotope C:

Mass of C = 26

Abundance (C%) = 11.17%

Average atomic mass of Mg =..?

The average atomic mass of Mg can be obtained as illustrated below:

Average atomic mass = [(Mass of A × A%)/100] + [(Mass of B × B%)/100] + [(Mass of C × C%)/100]

Average atomic mass = [(24 × 78.70)/100] + [(25 × 10.13)/100] + [(26 × 11.17)/100]

= 18.888 + 2.5325 + 2.9042

= 24.3247 ≈ 24.32

Therefore, the average atomic mass of magnesium (Mg) is 24.32

8 0

3 years ago

What element provides strength to the exoskeleton of Clams and oysters

Julli [10]

Phosphorus!!!! Hope this helps

8 0

2 years ago

How many moles of NaCl must be dissolved in 0.5 L of water to make a 4 mole/L

kvv77 [185]

C = 4 mol/l
v = 0.5 l

n(NaCl)=cv

n(NaCl) = 4 mol/l · 0.5 l = 2 mol

2 moles of NaCl must be dissolved

5 0

3 years ago

A gas used to extinguish fires is composed of 75 % CO2 and 25 % N2. It is stored in a 5 m3 tank at 300 kPa and 25 °C. What is th

tatyana61 [14]

Answer : The partial pressure of the $CO_2$ in the tank in psia is, 32.6 psia.

Explanation :

As we are given 75 % $CO_2$ and 25 % $N_2$ in terms of volume.

First we have to calculate the moles of $CO_2$ and $N_2$ .

$\text{Moles of }CO_2=\frac{\text{Volume of }CO_2}{\text{Volume at STP}}=\frac{75}{22.4}=3.35mole$

$\text{Moles of }N_2=\frac{\text{Volume of }N_2}{\text{Volume at STP}}=\frac{25}{22.4}=1.12mole$

Now we have to calculate the mole fraction of $CO_2$ .

$\text{Mole fraction of }CO_2=\frac{\text{Moles of }CO_2}{\text{Moles of }CO_2+\text{Moles of }N_2}$

$\text{Mole fraction of }CO_2=\frac{3.35}{3.35+1.12}=0.75$

Now we have to calculate the partial pressure of the $CO_2$ gas.

$\text{Partial pressure of }CO_2=\text{Mole fraction of }CO_2\times \text{Total pressure of gas}$

$\text{Partial pressure of }CO_2=0.75mole\times 300Kpa=225Kpa=225Kpa\times \frac{0.145\text{ psia}}{1Kpa}=32.625\text{ psia}$

conversion used : (1 Kpa = 0.145 psia)

Therefore, the partial pressure of the $CO_2$ in the tank in psia is, 32.6 psia.

3 0

3 years ago