True
the definition of matter is any substance that has mass and takes up space.
If the Ka of HCN = 5.0 x 10^-10
Since
(Ka) (Ka) - 1 x 10^ -14
then
the Kb of its conjugate base (CN-) = 2.0 X 10^-5
since
pH + pOH = 14
when the pH = 10.00
then
the pOH = 4.00
& the OH-
would then equal 1.0 X 10^-4
NaCN as a base does a hydrolysis in water:
CN- & water --> HCN & OH-
notice that equal amounts of OH- & HCN are formed
Kb = [HCN] [OH-] / [CN-]
2.0 X 10^-5 = [1.0 X 10^-4] [1.0 X 10^-4] / [CN-]
[CN-] =(1.0 X 10^-8) / (2.0 X 10^-5)
[CN-] = (5.0 X 10^-4)
that's 0.00050 Molar
which is 0.00050 moles in each liter of aqueous KCN solution
which is
0.00025 moles KCN in 500. mL of aqueous KCN solution
use molar mass of KCN, to find grams:
(0.00025 moles KCN) (65.12 grams KCN / mole) = 0.01628 grams of KCn
which is 16.3 mg of KCN
& rounded to the 2 sig figs which are showing in the Ka of HCN , "5.0" X 10^-10
your answer would be
16 mg of KCN
sorry even after making a correction in calcs , I don't get one of your answers.
the only way that I could get one of them is to pretend that yours was a 1 sig fig problem,
in which case your 16 mg would round off to 20 mg.
but you have 3 sig figs in "500. ml", & 2 sig figs in both the "pH of 10.00."
& The Ka of HCN = "5.0 x 10^-10."
it does however take 12 mg of NaCN, to make 500. mL of aqueous solution pH of 10.00. the molar mass of NaCN has the smaller molar mass of 49.00 grams per mole.
maybe they meant NaCN, but wrote KCN instead.
I hope i answered this correctly for you.
Answer:
B
Explanation:
If you are comparing an amount you are trying to find the quantity or the total of something or the size therefore answer B is the right answer
Hello!
1)Through vacuum, the fastest method of thermal energy transfer would be radiation. This kind of thermal energy transfer consists in energy carried out from a radiant body by electromagnetic waves at the speed of light e.g. the heat from the Sun. Radiation doesn't involve contact between the two bodies by any solid or fluid.
In the vacuum, the fastest way for heat to be transferred would be through radiation because the electromagnetic waves would be faster than any other heat transfer method and because there is no contact as there is no solid or fluid between the two bodies.
2) Through a gas: The fastest method of thermal energy transfer would be convection. Convection is the heat transfer by the real movement of molecules of a fluid. A gas is a fluid, and it would experience this kind of energy transfer as the molecules move.
Earth's atmosphere experience this kind of energy transfer, as large air masses move by convection, creating wind currents.
3) Through a solid: The fastest method of thermal energy transfer would be conduction. Conduction consists in the heat transfer between two bodies by molecular agitation but there is no movement involved i.e. the bodies are not fluids.
In the case of a solid, this kind of energy transfer will depend on a constant known as Thermal Conductivity, which allows assessing the ability to transfer heat through a solid.
Have a nice day!
Answer:
Cl
Explanation:
cl has mass number 35 and its atomic number is 17 so number of proton =atomic number 17 and number of neutron is =mass number -number of proton =35-17 =18
