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%
Answer: 243 hours
Explanation:
Expression for rate law for first order kinetics is given by:
where,
k = rate constant
t = age of sample
a = initial amount of the reactant = 
a - x = amount left after decay process = 
a) for completion of half life:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
b) for reducing the mass to 10.00 % of its original mass
The time taken to reach 10.00 % of its original mass is 243 hours
A3B2 because the oxidation numbers are the same as ionic charge just switch symbol and number. Then use the cross cross method and you get A3B2.
Answer:
Pb₂O₄
Explanation:
The given species are:
Pb⁴⁺ O²⁻
Now, to solve this problem, we use the combining powers which corresponds to the number of electrons usually lost or gained or shared by atoms during the course of a chemical combination.
Pb⁴⁺ O²⁻
Combining power 4 2
Exchange of valencies 2 4
Now the molecular formula is Pb₂O₄
