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Using the combined gas law

  1. An enclosed gas(i.e. one in a sealed container) has a volume of 300 cm 3 and a temperature of 300 K . The pressure of the gas is 50 kPa . Calculate the number of moles of gas that are present in the container.
  2. What pressure will 3 mol of gaseous nitrogen exert if it is pumped into a container that has a volume of 25 dm 3 at a temperature of 29 0 C ?
  3. The volume of air inside a tyre is 19 litres and the temperature is 290 K . You check the pressure of your tyres and find that the pressure is 190 kPa . How many moles of air are present in the tyre?
  4. 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 K and the number of moles of gas is 13 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 = n V

For this equation, the units for volume are dm 3 . Therefore, the unit of concentration is mol · dm - 3 . When concentration is expressed in mol · 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 is a measure of the amount of solute that is dissolved in a given volume of liquid. It is measured in mol · dm - 3 . Another term that is used for concentration is molarity (M)

If 3,5 g of sodium hydroxide (NaOH) is dissolved in 2,5 dm 3 of water, what is the concentration of the solution in mol · dm - 3 ?

  1. n = m M = 3 , 5 40 = 0 , 0875 mol
  2. C = n V = 0 , 0875 2 , 5 = 0 , 035

    The concentration of the solution is 0,035 mol · dm - 3 or 0,035 M

You have a 1 dm 3 container in which to prepare a solution of potassium permanganate ( KMnO 4 ). What mass of KMnO 4 is needed to make a solution with a concentration of 0,2 M ?

  1. C = n V


    n = C × V = 0 , 2 × 1 = 0 , 2 mol
  2. m = n × M = 0 , 2 × 158 , 04 = 31 , 61 g

    The mass of KMnO 4 that is needed is 31,61 g .

How much sodium chloride (in g) will one need to prepare 500 cm 3 of solution with a concentration of 0,01 M ?

  1. V = 500 1 000 = 0 , 5 dm 3
  2. n = C × V = 0 , 01 × 0 , 5 = 0 , 005 mol
  3. m = n × M = 0 , 005 × 58 , 45 = 0 , 29 g

    The mass of sodium chloride needed is 0,29 g

Molarity and the concentration of solutions

  1. 5,95 g of potassium bromide was dissolved in 400 cm 3 of water. Calculate its molarity.
  2. 100 g of sodium chloride (NaCl) is dissolved in 450 cm 3 of water.
    1. How many moles of NaCl are present in solution?
    2. What is the volume of water (in dm 3 )?
    3. Calculate the concentration of the solution.
    4. What mass of sodium chloride would need to be added for the concentration to become 5,7 mol · dm - 3 ?
  3. What is the molarity of the solution formed by dissolving 80 g of sodium hydroxide ( NaOH ) in 500 cm 3 of water?
  4. What mass (g) of hydrogen chloride ( HCl ) is needed to make up 1000 cm 3 of a solution of concentration 1 mol · dm - 3 ?
  5. How many moles of H 2 SO 4 are there in 250 cm 3 of a 0,8 M sulphuric acid solution? What mass of acid is in this solution?

Questions & Answers

are nano particles real
Missy Reply
Hello, if I study Physics teacher in bachelor, can I study Nanotechnology in master?
Lale Reply
no can't
where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
has a lot of application modern world
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
yes that's correct
I think
Nasa has use it in the 60's, copper as water purification in the moon travel.
nanocopper obvius
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
analytical skills graphene is prepared to kill any type viruses .
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What makes metals better to use as wires than non-metals? (please link to bonding type)??? HELP
Yash Reply

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Source:  OpenStax, Chemistry grade 10 [caps]. OpenStax CNX. Jun 13, 2011 Download for free at http://cnx.org/content/col11303/1.4
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