Answer:
54.1 % Ca, 43.2 % O, 2.7% H
Explanation:
Molecular formula for calcium hydroxide is Ca(OH)₂
As we don't have a mass of Ca(OH)₂ to find out the percentage composition, we consider that the question refers to 1 mol of compound.
1 mol of hydroxide weighs 74.08 g
1 mol of hydroxide has 1 mol of Ca, therefore 40.08 g are Ca
2 moles of O therefore 32g are O
2 moles of H therefore 2 g are H
Percentage composition is known as (Mass of element/Total mass) . 100
- (40.08 / 74.08) . 100 = 54.1 %
- (32 / 74.08) . 100 = 43.2 %
- (2 / 74.08) . 100 = 2.7%
The number of protons in an uncharged atom equals the number of electrons.
Answer:
22m/s
Explanation:
Given parameters:
Time = 5s
Acceleration = 4m/s²
Initial velocity = 2m/s
Unknown
Final speed = ?
Solution:
To solve this problem, we use the expression below;
v = u + at
v is the final speed
u is the initial speed
a is the acceleration
t is the time taken
So, insert the parameters and solve;
v = 2 + 4 x 5 = 22m/s
This means that there are 7 protons in the nucleus of a nitrogen atom.
Your answer is C for sure
