An enclosed gas(i.e. one in a sealed container) has a volume of
$300\phantom{\rule{2pt}{0ex}}\mathrm{cm}{}^{3}$ and a temperature of
$300\phantom{\rule{2pt}{0ex}}\mathrm{K}$ . The pressure of the gas is
$50\phantom{\rule{2pt}{0ex}}\mathrm{kPa}$ . Calculate the number of moles of gas that are present in the container.
What pressure will
$3\phantom{\rule{2pt}{0ex}}\mathrm{mol}$ of gaseous nitrogen exert if it is pumped into a container that has a volume of
$25\phantom{\rule{2pt}{0ex}}\mathrm{dm}{}^{3}$ at a temperature of
$29\phantom{\rule{2pt}{0ex}}{}^{0}\phantom{\rule{2pt}{0ex}}\mathrm{C}$ ?
The volume of air inside a tyre is 19 litres and the temperature is
$290\phantom{\rule{2pt}{0ex}}\mathrm{K}$ . You check the pressure of your tyres and find that the pressure is
$190\phantom{\rule{2pt}{0ex}}\mathrm{kPa}$ . How many moles of air are present in the tyre?
Compressed carbon dioxide is contained within a gas cylinder at a pressure of 700 kPa. The temperature of the gas in the cylinder is
$310\phantom{\rule{2pt}{0ex}}\mathrm{K}$ and the number of moles of gas is
$13\phantom{\rule{2pt}{0ex}}\mathrm{mols}$ of carbon dioxide. What is the volume of the gas inside the cylinder?
Molar concentrations of liquids
A typical solution is made by dissolving some solid substance in a liquid. The amount of substance that is dissolved in a given volume of liquid is known as the
concentration of the liquid. Mathematically, concentration (C) is defined as moles of solute (n) per unit volume (V) of solution.
$$C=\frac{n}{V}$$
For this equation, the units for volume are
$\mathrm{dm}{}^{3}$ . Therefore, the unit of concentration is
$\mathrm{mol}\xb7{\mathrm{dm}}^{-3}$ .
When concentration is expressed in
$\mathrm{mol}\xb7{\mathrm{dm}}^{-3}$ it is known as the
molarity (M) of the solution. Molarity is the most common expression for concentration.
Do not confuse molarity (M) with molar mass (M). Look carefully at the question in which the M appears to determine whether it is concentration or molar mass.
Concentration
Concentration is a measure of the amount of solute that is dissolved in a given volume of liquid. It is measured in
$\mathrm{mol}\xb7{\mathrm{dm}}^{-3}$ . Another term that is used for concentration is
molarity (M)
If
$\mathrm{3,5}\phantom{\rule{2pt}{0ex}}\mathrm{g}$ of sodium hydroxide (NaOH) is dissolved in
$\mathrm{2,5}\phantom{\rule{2pt}{0ex}}{\mathrm{dm}}^{3}$ of water, what is the concentration of the solution in
$\mathrm{mol}\xb7{\mathrm{dm}}^{-3}$ ?
The concentration of the solution is
$\mathrm{0,035}\phantom{\rule{2pt}{0ex}}\mathrm{mol}\xb7{\mathrm{dm}}^{-3}$ or
$\mathrm{0,035}\phantom{\rule{2pt}{0ex}}\mathrm{M}$
You have a
$1\phantom{\rule{2pt}{0ex}}{\mathrm{dm}}^{3}$ container in which to prepare a solution of potassium permanganate (
$\mathrm{KMnO}{}_{4}$ ). What mass of
$\mathrm{KMnO}{}_{4}$ is needed to make a solution with a concentration of
$\mathrm{0,2}\phantom{\rule{2pt}{0ex}}\mathrm{M}$ ?
The mass of
$\mathrm{KMnO}{}_{4}$ that is needed is
$\mathrm{31,61}\phantom{\rule{2pt}{0ex}}\mathrm{g}$ .
How much sodium chloride (in g) will one need to prepare
$500\phantom{\rule{2pt}{0ex}}{\mathrm{cm}}^{3}$ of solution with a concentration of
$\mathrm{0,01}\phantom{\rule{2pt}{0ex}}\mathrm{M}$ ?
The mass of sodium chloride needed is
$\mathrm{0,29}\phantom{\rule{2pt}{0ex}}\mathrm{g}$
Molarity and the concentration of solutions
$\mathrm{5,95}\phantom{\rule{2pt}{0ex}}\mathrm{g}$ of potassium bromide was dissolved in
$400\phantom{\rule{2pt}{0ex}}{\mathrm{cm}}^{3}$ of water. Calculate its molarity.
$100\phantom{\rule{2pt}{0ex}}\mathrm{g}$ of sodium chloride (NaCl) is dissolved in
$450\phantom{\rule{2pt}{0ex}}{\mathrm{cm}}^{3}$ of water.
How many moles of NaCl are present in solution?
What is the volume of water (in
${\mathrm{dm}}^{3}$ )?
Calculate the concentration of the solution.
What mass of sodium chloride would need to be added for the concentration to become
$\mathrm{5,7}\phantom{\rule{2pt}{0ex}}\mathrm{mol}\xb7{\mathrm{dm}}^{-3}$ ?
What is the molarity of the solution formed by dissolving
$80\phantom{\rule{2pt}{0ex}}\mathrm{g}$ of sodium hydroxide (
$\mathrm{NaOH}$ ) in
$500\phantom{\rule{2pt}{0ex}}{\mathrm{cm}}^{3}$ of water?
What mass (g) of hydrogen chloride (
$\mathrm{HCl}$ ) is needed to make up
$1000\phantom{\rule{2pt}{0ex}}{\mathrm{cm}}^{3}$ of a solution of concentration
$1\phantom{\rule{2pt}{0ex}}\mathrm{mol}\xb7{\mathrm{dm}}^{-3}$ ?
How many moles of
$\mathrm{H}{}_{2}\mathrm{SO}{}_{4}$ are there in
$250\phantom{\rule{2pt}{0ex}}{\mathrm{cm}}^{3}$ of a
$\mathrm{0,8}\phantom{\rule{2pt}{0ex}}\mathrm{M}$ sulphuric acid solution? What mass of acid is in this solution?
Questions & Answers
Is there any normative that regulates the use of silver nanoparticles?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?