Answer:
Iron remains = 17.49 mg
Explanation:
Half life of iron -55 = 2.737 years (Source)
Where, k is rate constant
So,
The rate constant, k = 0.2533 year⁻¹
Time = 2.41 years
![[A_0]](https://tex.z-dn.net/?f=%5BA_0%5D)
= 32.2 mg
Using integrated rate law for first order kinetics as:
![[A_t]=[A_0]e^{-kt}](https://tex.z-dn.net/?f=%5BA_t%5D%3D%5BA_0%5De%5E%7B-kt%7D)
Where,
![[A_t]](https://tex.z-dn.net/?f=%5BA_t%5D)
is the concentration at time t
is the initial concentration
So,
![[A_t]=32.2\times e^{-0.2533\times 2.41}\ mg](https://tex.z-dn.net/?f=%5BA_t%5D%3D32.2%5Ctimes%20e%5E%7B-0.2533%5Ctimes%202.41%7D%5C%20mg)
![[A_t]=32.2\times e^{-0.610453}\ mg](https://tex.z-dn.net/?f=%5BA_t%5D%3D32.2%5Ctimes%20e%5E%7B-0.610453%7D%5C%20mg)
![[A_t]=17.49\ mg](https://tex.z-dn.net/?f=%5BA_t%5D%3D17.49%5C%20mg)
<u>Iron remains = 17.49 mg</u>
Answer:
(a) oxygen
(b) 154g (to 3sf)
(c) 79.9% (to 3sf)
Explanation:
mass (g) = moles × Mr/Ar
note: eqn means chemical equation
(a)
moles of P = 84.1 ÷ 30.973 = 2.7152 moles
moles of O2 = 85÷2(16) = 2.65625 moles
Assuming all the moles of P is used up,
moles of O2 / moles of phosphorus = 5/4 (according to balanced chemical eqn)
moles of O2 required = 5/4 × 2.7152moles = 3.394 moles (more than supplied which is 2.65625moles)
therefore there is insufficient moles of O2 and the limiting reactant is oxygen.
(b)
moles of P2O5 produced
= 2/5 (according to eqn) × 2.7152
= 1.08608moles
mass of P2O5 produced
= 1.08608 × [ 2(30.973) + 5(16) ]
= 154.164g
= approx. 154g to 3 sig. fig.
(c)
% yield = actual/theoretical yield × 100%
= 123/154 × 100%
= 79.870%
= approx. 79.9% (to 3sf)
Answer:
its d, forming a hypothesis is always one of the first things you do, and d is the best answer from these 4
If there is more soil, there would be more plants, and thus, more organisms, depending on if the soil has enough nutrients to support an ecosystem. The way that this would affect the climate is that it would transpire moisture into the atmosphere, and also generate fresher air through photosynthesis.
Answer:
49.14 carat.
Explanation:
From the question given above, we obtained the following data:
Volume of diamond = 2.8 mL
Mass of diamond (in carat) =.?
Next, we shall determine the mass of diamond in grams (g). This can be obtained as follow:
Volume of diamond = 2.8 mL
Density of diamond = 3.51 g/mL
Mass of diamond ( in grams) =?
Density = mass /volume
3.51 = mass /2.8
Cross multiply
Mass of diamond (in g) = 3.51 × 2.8
Mass of diamond (in g) = 9.828 g
Finally, we shall Convert 9.828 g to carat. This can be obtained as follow:
1 g = 5 carat
Therefore,
9.828 g = 9.828 g /1 g × 5 carat
9.828 g = 49.14 carat.
Therefore, the mass of the diamond in carat is 49.14 carat.
