Answer:
Isotopes have same atomic numbers, no. of protons and no. of electrons. Only their no. of neutrons and atomic mass are changed.
<u>Na - 24:</u>
Atomic Mass = 24
Atomic No. = 11
Hence,
No. of protons in Na-24 = 11
No. of neutrons = Atomic Mass - Atomic Number
No. of neutrons = 24 - 11
No. of neutrons = 13
Atomic Number = 11
![\rule[225]{225}{2}](https://tex.z-dn.net/?f=%5Crule%5B225%5D%7B225%7D%7B2%7D)
Hope this helped!
<h3>~AH1807</h3><h3>Peace!</h3>
Answer:
The mole fraction of NaOH in an aqueous solution that contain 22.9% NaOH by mass=0.882
Explanation:
We are given that
Aqueous solution that contains 22.9% NaOH by mass means
22.9 g NaOH in 100 g solution.
Mass of NaOH(WB)=22.9 g
Mass of water =100-22.9=77.1
Na=23
O=16
H=1.01
Molar mass of NaOH(MB)=23+16+1.01=40.01
Number of moles =
Using the formula
Number of moles of NaOH

Molar mass of water=16+2(1.01)=18.02g
Number of moles of water

Now, mole fraction of NaOH
=

=0.882
Hence, the mole fraction of NaOH in an aqueous solution that contain 22.9% NaOH by mass=0.882
Cu + S ---> CuS
by reaction 1 mol 1 mol
from the problem 0.25 mol 0.25 mol
0.25 mol Cu
Answer:
0.74M
Explanation:
Step 1 :
Data obtained from the question.
Initial concentration (C1) = 3M
Initial volume (V2) = 185mL
Final volume (V2) = 750mL
Final concentration (C2) =..?
Step 2:
Determination of the new concentration of the solution.
The new concentration of the solution can be obtained by using the dilution formula as shown below:
C1V1 = C2V2
3 x 185 = C2 x 750
Divide both side by 750
C2 = 3 x 185 / 750
C2 = 0.74M
Therefore, the new concentration of the solution is 0.74M
Time taken = 3 hours
<h3>Further explanation</h3>
Given
speed : 75 mph
distance : 225 miles
Required
time taken
Solution
An equation of constant velocity motion

d = distance = m
v = speed = m / s
t = time = seconds
Input the value :
t = d : v
t = 225 miles : 75 miles/hour
t = 3 hours