To determine the density, we use the following formula:

mass= 2.813 grams
volume= ?
we need to first calculate the volume before we can solve for the density. since the question states that the sample has a spherical shape, we can use the volume formula of spheres to find it.

radius (r)=

=

let's plug in the values
V=

we need to change the

to

using the following conversion
1 cm= 10 mm

now we can find the density.
density= 2.813 grams/ 0.268 cm=
10.5 g/cm3
The mass of nitric acid required to make the given solution is 0.0627 g.
The given parameters:
- <em>Volume of the acid, V = 250 mL</em>
- <em>pH of the acid, = 2.4</em>
The hydrogen ion (H⁺) concentration of the nitric acid is calculated as follows;

The molarity of the nitric acid is calculated as follows;

The number of moles of the nitric acid is calculated as follows;

The molar mass of nitric acid is calculated as;

The mass of the nitric acid contained in the calculated number of moles is calculated as;

Thus, the mass of nitric acid required to make the given solution is 0.0627 g.
Learn more about molarity of acids here: brainly.com/question/13864682
Answer:
Name ; Nickel(ii)Hydroxide
Formula;NI3O6
Explanation:
Answer:
(a) 7.11x10⁻⁴ M/s
(b) 2.56 mol.L⁻¹.h⁻¹
Explanation:
(a) The reaction is:
O₃(g) + NO(g) → O₂(g) + NO₂(g) (1)
The reaction rate of equation (1) is given by:
(2)
<u>We have:</u>
k: is the rate constant of reaction = 3.91x10⁶ M⁻¹.s⁻¹
[O₃]₀ = 2.35x10⁻⁶ M
[NO]₀ = 7.74x10⁻⁵ M
Hence, to find the inital reacion rate we will use equation (2):
Therefore, the inital reaction rate is 7.11x10⁻⁴ M/s
(b) The number of moles of NO₂(g) produced per hour per liter of air is:
t = 1 h
V = 1 L
![\frac{\Delta[NO_{2}]}{\Delta t} = rate](https://tex.z-dn.net/?f=%5Cfrac%7B%5CDelta%5BNO_%7B2%7D%5D%7D%7B%5CDelta%20t%7D%20%3D%20rate)
![\frac{\Delta[NO_{2}]}{\Delta t} = 7.11 \cdot 10^{-4} M/s*\frac{3600 s}{1 h} = 2.56 mol.L^{-1}.h{-1}](https://tex.z-dn.net/?f=%5Cfrac%7B%5CDelta%5BNO_%7B2%7D%5D%7D%7B%5CDelta%20t%7D%20%3D%207.11%20%5Ccdot%2010%5E%7B-4%7D%20M%2Fs%2A%5Cfrac%7B3600%20s%7D%7B1%20h%7D%20%3D%202.56%20mol.L%5E%7B-1%7D.h%7B-1%7D)
Hence, the number of moles of NO₂(g) produced per hour per liter of air is 2.56 mol.L⁻¹.h⁻¹
I hope it helps you!