Answer:- 0.0211 moles of air.
Solution:- This problem is based on an ideal gas law equation.
temperature, pressure and volume are given and asked to calculate the moles of the air. Standard pressure is 1.00 atm.
T = 15 + 273 = 288 K
P = 1.00 atm
V = 0.500 L
The ideal gas law equation is, PV = nRT
where R is the universal gas law constant and its value is 0.0821 atm.L per mol per K.
n is the number of moles and its what we are asked to calculate.
For n, the equation is rearranged as:

Let's plug in the values and do the calculations:

n = 0.0211 moles
So, there are 0.0211 moles of the air in the bottle.
54.936 grams of NaCl will be produced from 33.0 g of Na and 34.0 g of Cl.
Explanation:
Data given:
mass of Na = 33 grams
mass of
= 24 grams
atomic mass of Na = 23 grams/moles
atomic mass of Cl = 70 grams/mole
mass of NaCl formed =?
atomic mass of NaCl = 58.44 gram/mole
balanced chemical reaction:
2Na +
⇒ 2NaCl
number of moles = 
putting the values in the equation:
number of moles of Na = 
= 0.69 moles
number of moles of chlorine gas = 
= 0.47 moles
limiting reagent is chlorine gas in the reaction
from the balanced chemical reaction:
1 mole of chlorine gas reacts to form 2 moles of NaCl
then 0.47 moles of chlorine gas will form x moles
= 
x = 0.94 moles of NaCl is formed.
mass = atomic mass x number of moles
mass = 58.44 x 0.94
= 54.936 grams of NaCl is produced.
Answer:
2.05*10⁻⁵ moles of CF₂ can dissolve in 100 g of water.
12.82 moles of CaF₂ will dissolve in exactly 1.00 L of solution
Explanation:
First, by definition of solubility, in 100 g of water there are 0.0016 g of CaF₂. So, to know how many moles are 0.0016 g, you must know the molar mass of the compound. For that you know:
- Ca: 40 g/mole
- F: 19 g/mole
So the molar mass of CaF₂ is:
CaF₂= 40 g/mole + 2*19 g/mole= 78 g/mole
Now you can apply the following rule of three: if there are 78 grams of CaF₂ in 1 mole, in 0.0016 grams of the compound how many moles are there?

moles=2.05*10⁻⁵
<u><em>2.05*10⁻⁵ moles of CF₂ can dissolve in 100 g of water.</em></u>
Now, to answer the following question, you can apply the following rule of three: if by definition of density in 1 mL there is 1 g of CaF₂, in 1000 mL (where 1L = 1000mL) how much mass of the compound is there?

mass of CaF₂= 1000 g
Now you can apply the following rule of three: if there are 78 grams of CaF₂ in 1 mole, in 1000 grams of the compound how many moles are there?

moles=12.82
<u><em>12.82 moles of CaF₂ will dissolve in exactly 1.00 L of solution</em></u>
The answer is calcium chloride.
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