Answer:
Number of moles = 0.057 × 10⁻⁷ mol
Explanation:
Given data:
Mass of SiO₂ = 3.4 × 10⁻⁷ g
Number of moles = ?
Solution:
Number of moles = mass/molar mass
Molar mass of SiO₂ = 60 g/mol
by putting values,
Number of moles = 3.4 × 10⁻⁷ g / 60 g/mol
Number of moles = 0.057 × 10⁻⁷ mol
Answer:
A. 28 years
Explanation:
Applying,
R = R'(2ᵃ/ⁿ).............. Equation 1
Where R = Original sample, R' = Sample left after decay, a = Total time taken to decay, n = half life.
From the question,
Given: R = 12 g, R' = 6 g, a = 28 years.
Substitute into equation 1 and solve for n
12 = 6(2²⁸/ⁿ)
12/6 = 2²⁸/ⁿ
2²⁸/ⁿ = 2
Equation the base,
28/n = 1
n = 28 years.
Hence the half-life is 28 years
Answer:
13.301
Explanation:
To calculate the pH of the solution, we must obtain the pOH of the solution as illustrated below:
The dissociation equation is given below
Ba(OH)2 <==> Ba^2+ + 2OH^-
Since Ba(OH)2 dissociate to produce 2moles of OH^-, the concentration of OH^- = 2x0.1 = 0.2M
pOH = - Log[OH^-]
pOH = - Log 0.2
pOH = 0.699
But
pH + pOH = 14
pH = 14 — pOH
pH = 14 — 0.699
pH = 13.301
In biological terms a cells main purpose is to survive but some important functions of cells are 1. Transports ( of molecules) 2. Chemical Reactions ( I.e Metabolism ) including energy conversion 3. reproduction hope this helps!
