Answer:
Percentage error = 1.88 %
Solution:
Data Given:
Mass of Sample = 20.46 g
Volume of Sample = 43.0 mL - 40.0 mL = 3.0 mL
Formula Used:
Density = Mass / Volume
Putting values,
Density = 20.46 g / 3.0 mL
Density = 6.82 g.mL⁻¹
Percentage Error:
Experimental Value = 6.82 g.mL⁻¹
Accepted Value = 6.95 g.mL⁻¹
= 6.82 g.mL⁻¹ / 6.95 g.mL⁻¹ × 100 = 98.12 %
Percentage Error = 100 % - 98.12 %
Percentage error = 1.88 %
The magnesium dissolves to form magnesium chloride and hydrogen gas is released.
Mg + 2HCl -----> MgCl2 + H2(g).
3Zn + 8HNO3 ---> 3Zn(NO3)2 + 4H2O + 2NO IF IT IS COLD AND DILUT NITRIC ACID .
IF IT IS HOT AND CONCENTRATED THEN:
Zn+ 4HNO3 ---> Zn(NO3)2 +2H2O +2NO2
Answer:
2 litres of pure alcohol will be added to make the overall concentration of 9 litres of mixture as 30%.
Explanation:
Suppose x is the number of litres added to the 10% mixture than the quantity of new mixture is given as below
litres
litres
Also the quantity of alcohol is given as
Now the equation is as

So 2 litres of pure alcohol will be added to make the overall concentration of 9 litres of mixture as 30%.