United Nations, people's Republic of China

United Nations, people's Republic of China

UN (United Nation)
PRC (people's Republic of China)

What is the primary unit of length measurement? What are the common units? How to convert?

M m others are kilometer km decimeter DM cm mm mm 1 m = 10 decimeter = 100 cm = 1000 mm, and light years and micrometers are not commonly used

The United States, China, Britain, Canada, their English abbreviations

USA
PRC of China
UK
Can Canada

When the mass fraction of solute in a solution is w, the density is pg / ml, and the molar mass is m, the mass concentration of substance in the solution can be calculated

Let the solution be 1 ml, that is 1000 ml;
Mass of solution = volume × density = 1000 ρ,
Mass of solute = mass of solution × w = 1000pw,
Therefore, the amount of solute is 1000 PW / m,
Mass concentration of substance = mass / volume of substance = (1000pw / M) / 1 = 1000pw / M

Suppose that the density of a solution is p, the molar mass of the solution is m, the mass fraction of solute is w, and the mass concentration of solute is C, the relationship between W and C is deduced

c=1000pw\m

In a saturated solution, the molar mass of solute is m, the density of solution is ρ, the mass concentration of solute is C, what is the solubility of solute?

Assuming that the solution is 1 L, the mass of solute is cx1xm = cm
The mass of the solution is 1000 x ρ = 1000 ρ
So the mass of water is 1000 ρ - cm
Let the solubility be SG, then S / 100 = cm / (1000 ρ - cm)
S=100CM/（1000ρ-CM）

Given the concentration of the substance, the density of the solution, calculate the mass percentage concentration formula

(mass concentration of substance * relative molecular mass of solute) / (solution density)

Calculation formula of mass concentration of substance
The derivation process of W = 1000 * density * solute mass fraction / m

In the derivation of the formula, the unit of density is usually g / ml, and the volume of solution is one liter
C=n/V
=(m/M)/V
=(1000D*W%/M)/1L
=1000 * density * solute mass fraction / M

Calculation of chemical substance concentration formula, (including density and mass fraction) and (including solubility)

Let m be the mass of solution, s be the solubility, W be the mass fraction, C be the mass concentration, and p be the density of solution
M is the molar mass of solute
C = amount of solute / volume of solution
1. Amount of solute = m * w / M
Solution volume = m / P
C = (MW / M) / (M / P)
Rearrangement C = PW / M
However, the unit of density is g / cm3 and the concentration of substance is mol / L
In order to unify the unit, C = 1000pw / m
2. If w = s / (100 + s) can be obtained in saturated solution with known solubility
We take W into C = 1000pw / m,
c=1000pS/[(100+S)M]
Note: the unit of C is mol / L, the unit of P is g / cm3, and the unit of S is g

Calculate the concentration of HCl in hydrochloric acid with 37% HCl mass fraction and 1.19 g / cm ^ 3 density

100ml hydrochloric acid is 119g hydrochloric acid, containing HCl 119 * 37% = 44.03g
The content of 100 ml hydrochloric acid: 44.03 / 36.5 = 1.206 mol
The concentration of the substance is 1.206mol/100ml = 12.06mol/l, that is 12n