Remember that
molecular substances (e.g. covalent compounds) may also dissolve, but most will not form ions. One example is sugar.
There are exceptions to this and some molecular substances
will form ions when they dissolve. Hydrogen chloride for example can ionise to form hydrogen and chloride ions.
Interesting fact
The ability of ionic compounds to dissolve in water is extremely important in the human body! The body is made up of
cells , each of which is surrounded by a
membrane . Dissolved ions are found inside and outside of body cells in different concentrations. Some of these ions are positive (e.g.
) and some are negative (e.g.
). If there is a difference in the charge that is inside and outside the cell, then there is a
potential difference across the cell membrane. This is called the
membrane potential of the cell. The membrane potential acts like a battery and affects the movement of all charged substances across the membrane. Membrane potentials play a role in muscle functioning, digestion, excretion and in maintaining blood pH to name just a few. The movement of ions across the membrane can also be converted into an electric signal that can be transferred along
neurons (nerve cells), which control body processes. If ionic substances were not able to dissociate in water, then none of these processes would be possible! It is also important to realise that our bodies can
lose ions such as
,
,
,
, and
, for example when we sweat during exercise. Sports drinks such as Lucozade and Powerade are designed to replace these lost ions so that the body's normal functioning is not affected.
Write a balanced equation to show how silver nitrate (
) dissociates in water.
The cation is:
and the anion is:
Since we know both the anion and the cation that silver nitrate dissociates into we can write the following equation:
Ions in solution
For each of the following, say whether the substance is ionic or molecular.
potassium nitrate (
)
ethanol (
)
sucrose (a type of sugar) (
)
sodium bromide (
)
Write a balanced equation to show how each of the following ionic compounds dissociate in water.
sodium sulphate (
)
potassium bromide (
)
potassium permanganate (
)
sodium phosphate (
)
Ions and water hardness
This section is not examinable and is included as an example of ions in aqueous solution.
Water hardness
Water hardness is a measure of the mineral content of water. Minerals are substances such as calcite, quartz and mica that occur naturally as a result of geological processes.
Hard water is water that has a high mineral content. Water that has a low mineral content is known as
soft water . If water has a high mineral content, it usually contains high levels of metal ions, mainly calcium (
) and magnesium (
). The calcium enters the water from either
(limestone or chalk) or from mineral deposits of
. The main source of magnesium is a sedimentary rock called dolomite,
. Hard water may also contain other metals as well as bicarbonates and sulphates.
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?
