GCSE Chemistry Revision "Concentration of Solutions"
Summary
TLDRIn this Free Science video, viewers learn how to calculate the concentration of a solution in grams per decimeter cubed. The lesson explains that concentration is the mass of solute per given volume of solution, with water often serving as the solvent. The video demonstrates calculations using a formula and offers practice problems. Higher-tier students also explore how changes in solute mass and solution volume affect concentration, making this an informative resource for understanding chemical solutions.
Takeaways
- š The concentration of a solution is defined as the mass of solute in a given volume of solution.
- š Higher tier students will learn an additional definition of concentration later, but Foundation students only need to learn this one.
- š§ A solute is a chemical that is dissolved in a solvent, commonly water in chemistry.
- š¢ The unit of concentration is grams per decimeter cubed (g/dmĀ³), which is equivalent to grams per liter.
- š The concentration is calculated using the formula: concentration (g/dmĀ³) = mass (g) / volume (dmĀ³).
- š A triangle diagram is used to help remember the formula for calculating concentration.
- š§Ŗ Example calculation: 200 g of a chemical dissolved in water to a final volume of 1 dmĀ³ results in a concentration of 200 g/dmĀ³.
- š§ Challenging calculation: 150 g of a chemical dissolved in water to a final volume of 0.5 dmĀ³ results in a concentration of 300 g/dmĀ³.
- š The equation can be rearranged to calculate either the mass of a solute or the volume of a solution given the concentration.
- š If the mass of solute is increased while the volume remains constant, the concentration increases.
- š If the volume of the solution is increased while the mass of solute remains constant, the concentration decreases.
Q & A
What is the definition of concentration in the context of this video?
-Concentration refers to the mass of a solute in a given volume of solution, expressed in grams per decimeter cubed (g/dmĀ³).
What is a solute in chemistry?
-A solute is a chemical that is dissolved in a solvent, with water being a common solvent in chemistry.
What is the unit of concentration used in this video?
-The unit of concentration used is grams per decimeter cubed (g/dmĀ³), which is equivalent to grams per liter.
How is concentration calculated according to the video?
-Concentration is calculated by dividing the mass of the solute in grams by the volume of the solution in decimeters cubed.
What is the concentration of a solution if 200 g of a chemical is dissolved in water to a final volume of 1 dmĀ³?
-The concentration would be 200 g/dmĀ³ since the mass (200 g) divided by the volume (1 dmĀ³) equals 200 g/dmĀ³.
How would you calculate the concentration if 150 g of a chemical is dissolved in water to a final volume of 0.5 dmĀ³?
-The concentration would be 300 g/dmĀ³, calculated by dividing the mass (150 g) by the volume (0.5 dmĀ³).
What is the mass of a chemical needed to achieve a concentration of 600 g/dmĀ³ in a final volume of 0.4 dmĀ³?
-The mass needed would be 240 g, calculated by multiplying the concentration (600 g/dmĀ³) by the volume (0.4 dmĀ³).
How do you find the final volume of a solution containing 200 g of a chemical with a concentration of 800 g/dmĀ³?
-The final volume would be 0.25 dmĀ³, found by dividing the mass (200 g) by the concentration (800 g/dmĀ³).
How does increasing the mass of the solute affect the concentration if the volume of the solution remains the same?
-Increasing the mass of the solute while keeping the volume constant will increase the concentration of the solution.
What happens to the concentration if the volume of the solution is increased while the mass of the solute remains the same?
-If the volume of the solution is increased and the mass of the solute remains the same, the concentration of the solution will decrease.
What additional resources are available for practicing concentration calculations as mentioned in the video?
-The video mentions a revision workbook with more questions on concentration, which can be accessed by clicking on the provided link.
Outlines
š¬ Introduction to Solution Concentration
The script starts with an introduction to the concept of concentration in chemistry, specifically focusing on how it's calculated in grams per decimeter cubed (g/dmĀ³). It clarifies that for higher tier students, there will be an additional definition of concentration in later videos, but foundation students need only learn this one. The script defines a solute as a chemical dissolved in a solvent, typically water, and explains that the concentration can be calculated using the formula: concentration (g/dmĀ³) = mass (g) / volume (dmĀ³). A visual aid in the form of a triangle is mentioned to help with learning this equation. The script then poses a question to calculate the concentration of a solution with 200 g of a chemical dissolved in water to a final volume of 1 dmĀ³, resulting in a concentration of 200 g/dmĀ³.
š§Ŗ Calculating Concentration with Different Volumes
The script challenges viewers with a more complex question involving a chemical dissolved in water to a final volume of 0.5 dmĀ³, asking to calculate the concentration. The correct answer, obtained by dividing 150 g by 0.5 dmĀ³, is 300 g/dmĀ³. The video then suggests rearranging the concentration equation to calculate either the mass of a solute or the volume of a solution. An example question is given where viewers are asked to calculate the mass of a chemical needed to achieve a concentration of 600 g/dmĀ³ in a final volume of 0.4 dmĀ³. The correct calculation involves multiplying the concentration by the volume, yielding a mass of 240 g.
š Advanced Questions on Concentration
The script presents another question for viewers to calculate the final volume of a solution containing 200 g of a chemical with a concentration of 800 g/dmĀ³. The correct approach is to divide the mass by the concentration, resulting in a final volume of 0.25 dmĀ³. The script then explains that higher tier students need to understand how the mass of the solute and the volume of the solution affect the concentration. Two key facts are highlighted: increasing the mass of the solute while keeping the volume constant increases the concentration, and increasing the volume of the solution while keeping the mass of the solute constant decreases the concentration. The video concludes by directing viewers to a revision workbook for more practice questions on concentration.
Mindmap
Keywords
š”Concentration
š”Solute
š”Solvent
š”Decimeter Cubed (dmĀ³)
š”Mass
š”Volume
š”Higher Tier Students
š”Equation
š”Rearranging Equation
š”Concentration Effects
š”Revision Workbook
Highlights
Introduction to calculating the concentration of a solution in grams per decimeter cubed
Explanation for higher tier students about additional concentration definitions
Definition of solute and solvent in chemistry
Concentration unit is grams per decimeter cubed, formerly known as grams per liter
Concentration calculation formula: mass in grams divided by volume in decimeters cubed
Visual aid in the form of a triangle to help memorize the concentration formula
Example calculation: 200 g of a chemical dissolved in water to a final volume of 1 DM cubed
Result of the example calculation: concentration of 200 g per decimeter cubed
Challenger question: calculating concentration with 150 g of a chemical dissolved in 0.5 DM cubed
Result of the challenging calculation: concentration of 300 g per decimeter cubed
Instruction on rearranging the concentration equation to find mass or volume
Example problem: calculating the mass needed for a specific concentration and volume
Solution to the example problem: multiplying concentration by volume to find mass
Another example problem: calculating the final volume of a solution with a given mass and concentration
Solution to the volume calculation: dividing mass by concentration
Explanation for higher tier students on how mass and volume affect concentration
Two key facts for higher tier students regarding concentration changes
Availability of more concentration questions in the revision workbook
Summary of the lesson's learning objectives
Transcripts
[Music]
hi and welcome back to free science
lessons. co.uk by the end of this video
you should be able to calculate the
concentration of a solution in grams per
desm cubed higher tier students should
also be able to explain how the mass of
the solute and the volume of the
solution affect the
concentration so let's start by looking
at what's meant by concentration the
concentration tells us the mass of a
solute in a given volume of solution now
I should point out that if you're a
higher tier student you learn another
definition of concentration as well as
this one in a later video but if you're
doing Foundation then you only need to
learn this
definition so what's meant by a solute
well a solute is a chemical which is
dissolved in a solvent and in chemistry
water is often used as a
solvent the unit of concentration for
this definition is G per decim cubed a
cubed is what used to be called a liter
but scientists don't use that word
anymore now we calculate the
concentration using this equation this
equation is not in the spec but I do
think it's worth learning the
concentration in grams per decimeter
cubed is the mass in grams divided by
the volume in decimet cubed and here's a
triangle to help you learn
this so let's look at a typical question
200 g of a chemical is dissolved in
water to a final volume of 1 DM cu cubed
calculate the concentration of the
solution here's the
equation to find the concentration we
divide the mass and grams by the volume
in decimet cubed this gives us a final
concentration of 200 g per decim cubed
now that was quite an easy one so let's
look at something a bit more
challenging 150 g of a chemical is
dissolved in water to a final volume of
0.5 DM cubed calculate the concentration
of the solution pause the video and try
this
yourself okay dividing 150 G by 0.5 DM
cubed gives us a final concentration of
300 G per decim
cubed okay now in the exam you could be
asked to rearrange this equation and
calculate the mass of a solute or the
volume of a solution so here's another
question for you to
try calculate the mass of a chemical
needed to dissolve in a final volume of
0.4 DM cubed to give a concentration of
600 G per per decim cubed now to answer
this question it's worth using the
triangle pause the video and try this
yourself we're calculating Mass so we
multiply the concentration by the volume
multiplying 600 by .4 gives us a final
mass of 240
G here's one more question for you to
try calculate the final volume of a
solution containing 200 g of a chemical
with a concentration of 800 G per decim
cubed here's a triangle pause the video
and try this
yourself okay we're calculating the
volume so we need to divide the mass by
the
concentration 200 g ID 800 G per decim
cubed gives us a final volume of .25
decim
cubed now if you're a higher student you
need to be able to explain how the mass
of the solute and the volume of the
solution affect the
concentration here are the two facts
that you need to know if we increase the
mass of solute and keep the volume the
same then we increase the
concentration if we increase the volume
of the solution and keep the mass of the
solute the same then we decrease the
concentration remember that you'll find
plenty more questions on concentration
in my revision workbook which you can
get by clicking on the link
above okay so hopefully now you should
be able to calculate the concentration
of a solution and grams per decimeter
cubed and if you're a higher tier
student you should be able to explain
how the mass of the solute and the
volume of the solution affect the
[Music]
concentration
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