Answer:
12.50g
Explanation:
T½ = 2.5years
No = 100g
N = ?
Time (T) = 7.5 years
To solve this question, we'll have to find the disintegration constant λ first
T½ = In2 / λ
T½ = 0.693 / λ
λ = 0.693 / 2.5
λ = 0.2772
In(N/No) = -λt
N = No* e^-λt
N = 100 * e^-(0.2772*7.5)
N = 100*e^-2.079
N = 100 * 0.125
N = 12.50g
The sample remaining after 7.5 years is 12.50g
I can think of 2 off the top of my head first is friction and second is gravity
The amount ( in moles of excess reactant that is left is 0.206 moles
Explanation
FeS(s) + 2HCl (aq) → FeCl2 (s) + H2S (g)
- by use of mole ratio of FeS: HCl which is 1:2 this means that 0.223 mole of FeS reacted completely with 0.223 x 2/1 =0.446 moles 0f FeCl2.
- HCl was in excess because 0.446 moles of HCl reacted and initially there was 0.652 moles.
- Therefore the amount that was left
= 0.652- 0.446 =0.206 moles
Burning and other changes in matter do not destroy matter. The mass of matter is always the same before and after the changes occur. The law of conservation of mass states that matter cannot be created or destroyed
<h2>Answer:</h2>
The three examples of convection are
- The stack effect
- Oceanic circulation
- Hot air balloon
<h2>Explanation:</h2>
The stack effect is also referred to as the chimney effect which is the movement of air inside and outside of buildings, flues or any other objects because of buoyancy principle. In oceanic circulation warm water around the equator circulates towards the poles and the cooler water at the poles moves towards the equator. In hot air balloon, a heater inside the balloon heats the air and so the air moves upward.
