Given :
Volume of NaCl solution 2.5 L .
Molarity of NaCl solution is 0.070 M .
To Find :
How many moles are present in the solution.
Solution :
Let, n be the number of moles.
We know, molarity is given by :

So,
 
Therefore, number of moles of NaCl is 0.175 moles.
 
        
             
        
        
        
Answer:
Required number of moles of ideal gas is 0.877 moles.
Explanation:
Pressure (P) = 0.850 atm
Temperature (T) = 295 K
Volume (V) = 25 ltr
Universal gas constant (R) = 0.0821
no of moles (n) = ?
we have the ideal gas equation as:
                             PV= nRT
                 or, 0.850× 25 = n × 0.0821 × 295
                 or, n = 0.877 moles
Hence the required number of moles of an ideal gas is 0.877 moles.
 
        
             
        
        
        
RbOH is a strong base that dissociates completely and HCl is a strong acid that too dissociates completely. the complete reaction between the acid and base is;
RbOH + HCl ---> RbCl + H₂O
stoichiometry of acid to base is 1:1
At neutralisation point
H⁺ mol = OH⁻ mol
mol = molarity x volume 
if Ma - molarity of acid and Va - volume of acid reacted
Mb - molarity of base and Vb - volume of base reacted 
Ma x Va = Mb x Vb
0.5 M x 52.8 mL = Mb x 60.0 mL 
Mb = 0.44 M 
molarity of base - 0.44 M 
        
             
        
        
        
MgF₂ ( <span>Magnesium fluoride )
hope this helps!</span>
        
             
        
        
        
Answer:
36.09% is the mass percent composition of calcium in calcium chloride
Explanation:
Mass percent is defined as one hundred times the ratio between the mass of a compound (In this case, Calcium), and the total mass of the sample:
<em>Mass Percent = Mass compound / Total mass of the sample × 100</em>
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Computing the values of the problem:
Mass Percent = 0.690g / 1.912g * 100
Mass percent = 
<h3>36.09% is the mass percent composition of calcium in calcium chloride</h3>