What do you need help with. I am very good at chemistry.
Answer : The density of an object is, 
Solution : Given,
Mass of an object = 60 g
Volume of an object = 
Formula used :

Now put all the given values in this formula, we get the density of an object.

Therefore, the density of an object is, 
Answer:
C
Explanation:
A diatomic element in that list is Bromine
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 %