Answer:
The correct answer is <em>D) Niels Bohr</em>
Explanation:
Bohr proposed a new atomic model, whereby he explains that electrons rotate around the nucleus at well-defined levels, describing circular orbits. Each orbit was called the energy level (it is called the main quantum number n, going from numbers 1 to 7). To make his model, Bohr studied the Hydrogen atom (it has a proton in its nucleus and an electron rotating around it).
Because it is balanced with protons and electrons
The volume of the given solution is 2.5 L.
<u>Explanation:</u>
Volume of the solution = 2500 mL
We have to convert it into litres as,
1000 mL = 1 litre
To convert ml into litres we have to divide the millilitres by 1000, so that it can be converted into L.
Here given volume is 2500 mL.
Volume in L =
= 2.5 L
So the volume of the solution is 2.5 L.
Answer:
Moles of carbon dioxide gas is 0.584 moles.
Mass of 0.584 moles of carbon dioxide gas is 25.7 g
Explanation:
Using ideal gas equation
PV = nRT
where,
P = Pressure of gas = 
V = Volume of gas = 30.0 L
n = number of moles of gas = ?
R = Gas constant = 0.0821 L.atm/mol.K
T = Temperature of gas = 27°C = 300.15 K
Putting values in above equation, we get:

Moles of carbon dioxide gas = 0.584 moles
Mass of 0.584 moles of carbon dioxide gas = 0.584 mol × 44 g/mol = 25.69 g ≈ 25.7 g
1. Answer:
1.0 × 10–9 M OH–
Explanation:
pH = -Log[H+]
pOH = -Log[OH-]
But;
pH + pOH = 14
Therefore;
[H+] + [OH-] = 1.0 × 10^-14 M
Therefore;
[OH-] = 1.0 × 10^-14 M - (1.0 × 10^–5 M)
= 1.0 × 10^-9 M OH–
2. Answer;
pH = 7.28
Explanation;
pH = -Log[H3O+]
Given;
[H3O+] = 5.2 × 10^–8 M
Therefore;
pH = - log [5.2 × 10^–8 M]
= 7.28
The pH is 7.28