When you are busy with these calculations, you will need to remember the following:
1dm
= 1 litre = 1000ml = 1000cm
, therefore dividing cm
by 1000 will give you an answer in dm
.
Some other terms and equations which will be useful to remember are shown below:
Molarity is a term used to describe the concentration of a solution, and is measured in mol.dm
. The symbol for molarity is M. Refer to chapter
[link] for more information on molarity.
Moles = molarity (mol.dm
) x volume (dm
)
Molarity (mol.dm
) =
Given the equation:
25cm
of a sodium hydroxide solution was pipetted into a conical flask and titrated with 0.2M hydrochloric acid. Using a suitable indicator, it was found that 15cm
of acid was needed to neutralise the alkali. Calculate the molarity of the sodium hydroxide.
NaOH: V = 25 cm
HCl: V = 15 cm
; C = 0.2 M
The equation is already balanced.
Therefore, n(HCl) = M
V (make sure that all the units are correct!)
M = 0.2mol.dm
V = 15cm
= 0.015dm
Therefore
There are 0.003 moles of HCl that react
Look at the equation for the reaction. For every mole of HCl there is one mole of NaOH that is involved in the reaction. Therefore, if 0.003 moles of HCl react, we can conclude that the same quantity of NaOH is needed for the reaction. The number of moles of NaOH in the reaction is 0.003.
First convert the volume into dm
. V = 0.025 dm
. Then continue with the calculation.
The molarity of the NaOH solution is 0.12 mol.dm
or 0.12 M
4.9 g of sulfuric acid is dissolved in water and the final solution has a volume of 220 cm
. Using titration, it was found that 20 cm
of this solution was able to completely neutralise 10 cm
of a sodium hydroxide solution. Calculate the concentration of the sodium hydroxide in mol.dm
.
M = n/V
V = 220 cm
= 0.22 dm
Therefore,
Remember that only 20 cm
of the sulfuric acid solution is used.
M = n/V, therefore n = M
V
According to the balanced chemical equation, the mole ratio of H
SO
to NaOH is 1:2. Therefore, the number of moles of NaOH that are neutralised is 0.0046
2 = 0.0092 mols.
Demonstration : the reaction of acids with carbonates
Apparatus and materials:
Small amounts of sodium carbonate and calcium carbonate (both in powder form); hydrochloric acid and sulfuric acid; retort stand; two test tubes; two rubber stoppers for the test tubes; a delivery tube; lime water. The demonstration should be set up as shown below.
Questions & Answers
A golfer on a fairway is 70 m away from the green, which sits below the level of the fairway by 20 m. If the golfer hits the ball at an angle of 40° with an initial speed of 20 m/s, how close to the green does she come?
A mouse of mass 200 g falls 100 m down a vertical mine shaft and lands at the bottom with a speed of 8.0 m/s. During its fall, how much work is done on the mouse by air resistance
Chemistry is a branch of science that deals with the study of matter,it composition,it structure and the changes it undergoes
Adjei
please, I'm a physics student and I need help in physics
Adjanou
chemistry could also be understood like the sexual attraction/repulsion of the male and female elements. the reaction varies depending on the energy differences of each given gender. + masculine -female.
Pedro
A ball is thrown straight up.it passes a 2.0m high window 7.50 m off the ground on it path up and takes 1.30 s to go past the window.what was the ball initial velocity
2. A sled plus passenger with total mass 50 kg is pulled 20 m across the snow (0.20) at constant velocity by a force directed 25° above the horizontal. Calculate (a) the work of the applied force, (b) the work of friction, and (c) the total work.
you have been hired as an espert witness in a court case involving an automobile accident. the accident involved car A of mass 1500kg which crashed into stationary car B of mass 1100kg. the driver of car A applied his brakes 15 m before he skidded and crashed into car B. after the collision, car A s
can someone explain to me, an ignorant high school student, why the trend of the graph doesn't follow the fact that the higher frequency a sound wave is, the more power it is, hence, making me think the phons output would follow this general trend?
Nevermind i just realied that the graph is the phons output for a person with normal hearing and not just the phons output of the sound waves power, I should read the entire thing next time
Joseph
Follow up question, does anyone know where I can find a graph that accuretly depicts the actual relative "power" output of sound over its frequency instead of just humans hearing
Joseph
"Generation of electrical energy from sound energy | IEEE Conference Publication | IEEE Xplore" ***ieeexplore.ieee.org/document/7150687?reload=true
A string is 3.00 m long with a mass of 5.00 g. The string is held taut with a tension of 500.00 N applied to the string. A pulse is sent down the string. How long does it take the pulse to travel the 3.00 m of the string?
