<em>C = 0,75 mol/dm³</em>
<em>V = 500mL = 500cm³ = 0,5dm³</em>
C = n/V
n = 0,75×0,5dm³
<u>n = 0,375 moles</u>
<em>M NaCl: 23+35,5 = 58,5g</em>
1 mole ---------- 58,5g
0,375 ----------- X
X = 0,375×58,5
<u>X = 21,9375g NaCl</u>
:)

<h3>Further explanation</h3>
Given
3000 L of gas at 39°C and 99 kPa to 45.5 kPa and 16°C,
Required
the new volume
Solution
Combined with Boyle's law and Gay Lussac's law

T₁ = 39 + 273 = 312
T₂ = 16 + 273 = 289
Input the value :
V₂ = (P₁V₁.T₂)/(P₂.T₁)
V₂ = (99 x 3000 x 289)/(45.5 x 312)
or we can write it as:
V₂ = 3000 L x (289/312) x (99/45.5)
The fourth one: Gain of an electron
Answer:
b. .28 M KCI
Explanation:
Use the dilution formula.
C₁V₁ = C₂V₂
C₂ = C₁V₁/V₂
C₂ = 1.6*0.175 / 1.0
C₂ = 0.28
Answer:
B
Explanation:
Assuming the units are all supposed to be the same
A cube shaped cell with a 1 um³ volume would have a dimensions of 1 x 1 x 1 (because volume = length x width x height and 1 x 1 x 1 =1)
If we double the dimensions, we have a cube with the dimensions 2 x 2 x 2.
The surface area of each face of the cube is the length x width, so 2 x 2. This means the surface area of each face of the cube is 4 um².
There are 6 faces of a cube, so the total surface area is 6 x 4 um² = 24 um².