Answer:
Example
0.5 mol of sodium hydroxide is dissolved in 2 dm3 of water. Calculate the concentration of the sodium hydroxide solution formed.
Concentration =
Concentration = 0.25 mol/dm3
Volume units
Volumes used in concentration calculations must be in dm3, not in cm3. It is useful to know that 1 dm3 = 1000 cm3. This means:
divide by 1000 to convert from cm3 to dm3
multiply by 1000 to convert from dm3 to cm3
For example, 250 cm3 is 0.25 dm3 (250 ÷ 1000). It is often easiest to convert from cm3 to dm3 before continuing with a concentration calculation.
Question
100 cm3 of dilute hydrochloric acid contains 0.02 mol of dissolved hydrogen chloride. Calculate the concentration of the acid in mol/dm3.
Reveal answer
Converting between units
The relative formula mass of the solute is used to convert between mol/dm3 and g/dm3:
to convert from mol/dm3 to g/dm3, multiply by the relative formula mass
to convert from g/dm3 to mol/dm3, divide by the relative formula mass
Remember: the molar mass is the Ar or Mr in grams per mol.
Example
Calculate the concentration of 0.1 mol/dm3 sodium hydroxide solution in g/dm3. (Mr of NaOH = 40)
Concentration = 0.1 × 40
= 4 g/dm3
35 b.
37 h
39 i
41 d
hope that helps
Explanation:
The given chemical equation is:
The rate of the reaction is 0.0352 M/s.
During the course of the reaction, the rate of reactants decreases, and the rate of products increases.
The rate of disappearance of B is shown below:
![rate=-\frac{1}{4} \frac{d[B]}{dt}](https://tex.z-dn.net/?f=rate%3D-%5Cfrac%7B1%7D%7B4%7D%20%5Cfrac%7Bd%5BB%5D%7D%7Bdt%7D)
So, rate of change of B is :
Option C.
The statement that correctly compares protons, electrons, and neutrons is, "Quarks are present in protons and neutrons but not in electrons". Quarks are tiny particles which compose the neutrons and protons. These quarks in protons and neutrons are linked together by gluons.
Kinetic energy is the energy in motion. The higher the temperature, the higher the motion of molecules. Therefore from the choices, water vapor at 102C has the highest kinetic energy.
