part a;
the equation for molarity, m, is
m=n/v
where v is volume and n is the number of moles of solute.
a certain solution has a molarity of m = 2.73 mol/l and has a volume of v = 0.650 l . what is the value of n?
express your answer numerically in moles.
part b;
the equation for photon energy, e, is
e=hcλ
where h = 6.626×10−34 j⋅s (planck's constant) and c = 2.99×108 m/s (the speed of light).
what is the wavelength, λ, of a photon that has an energy of e = 3.98×10−19 j ?
express your answer numerically in meters.
part c;
the ideal gas equation is
pv=nrt
where p is pressure, v is volume, n is the number of moles, r is a constant, and t is temperature.
you are told that a sample of gas has a pressure of p = 899 torr , a volume of v = 3280 ml, and a temperature of t = 307 k . if you use r = 8.206×10−2 l⋅atm/(k⋅mol) , which of the following conversions would be necessary before you could find the number of moles of gas, n, in this sample?
check all that apply.
view available hint(s)
check all that apply.
convert the pressure to atmospheres (atm).
convert the pressure to pascals (pa).
convert the volume to cubic meters (m3).
convert the volume to liters (l).
convert the temperature to degrees celsius (∘c).
convert the temperature to degrees fahrenheit (∘f).

Part A : n = 1.77 moles

Part B : λ =

Part C : n = 0.154 moles

Explanation:

Part A

The problem gives you the equation for molarity M:

n is the number of moles of solute and V is the volume

Then the problem gives you the molarity of a substance and the volume V = 0.650L, so you need to solve the equation for n:

as the V is dividing it passes to multiply the M:

n = M*V

and you should replace the values:

n = 1.77 moles

Part B

This time you have to solve the equation E = hcλ for λ that is the unknown information, so you have:

E = hcλ

h and c are multiplying so they pass to divide the E:

λ =

and replacing the values:

λ =

λ =

PartC

In this part the problem gives you the equation PV=nRT and the first thing you should do is to verify that all the quantities are in consistent units so:

so you need to convert the pressure to atmospheres and convert the volume to liters.

- Convert the pressure to atmospheres:

P = 1.18 atm

- Convert the volume to liters:

V = 3.28L

To find the number of moles n, you should solve the equation for n:

Pv = nRT

As R and T are multiplying the n, they pass to divide to the other side of the equation:

And finally you should replace the values:

n = 0.154 moles

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-

explanation:

a