Answer:
true
Explanation:
This is because it helps distribute the particles that are being dissolved. 
 
        
                    
             
        
        
        
Answer:
its a chemical formula, it has numbers and symbols
 
        
                    
             
        
        
        
Covalent compounds: N2, CCl4, SiO2 and AlCl3.
Ionic compounds: CaCl2 and LiBr.
Hope this helps!
        
             
        
        
        
Answer:
Synthetic detergents can be used for washing purposes even when the water is hard, whereas soaps are not suitable for washing with hard water. This is because of the fact that synthetic detergents can lather with hard water. Hence, Synthetic detergents better than soaps.
 
        
                    
             
        
        
        
Answer:
a) 1,6%
b) 64,775 g/mol
c) 3,6×10⁻² M
d) 2,3×10⁻³ g/mL
Explanation:
a) The mass fractium of helium is obtained converting the moles of the four gases to grams with molar weight and then caculating of the total of grams how many are of helium, thus:
- Helium: 0,25 moles × = 1 g of Helium = 1 g of Helium
- Argon: 0,25 moles × = 10 g of Argon = 10 g of Argon
- Krypton: 0,25 moles × = 20,95 g of krypton = 20,95 g of krypton
- Xenon: 0,25 moles × = 32,825 g of Xenon = 32,825 g of Xenon
Total grams: 1g+10g+20,85g+30,825g= 62,675 g
Mass fraction of helium:  × 100 = <em>1,6%</em>
 × 100 = <em>1,6%</em>
<em />
<em>The mass fraction of Helium is 1,6%</em>
<em />
<em>b)</em><em>  </em>Because the mole fraction of all gases is the same the average molecular weight of the mixture is:
 = 64,775 g/mol
 = 64,775 g/mol
c) The molar concentration is possible to know ussing ideal gas law, thus:
 = M
 = M
Where:
P is pressure: 150 kPa
R is gas constant: 8,3145
T is temperature: 500 K
And M is molar concentration. Replacing:
M = 3,6×10⁻² M
d) The mass density is possible to know converting the moles of molarity to grams with average molecular weight and liters to mililiters, thus:
3,6×10⁻²  ×
 ×  ×
 ×  =
 =
2,3×10⁻³ g/mL
I hope it helps!