Carbon will have 4 valence electrons. It will have 2 in the p orbital and 2 in the s orbital. You can see this when you find the noble gas configuration of carbon which is [He]2s²2p² showing that carbon has 4 valence electrons.
I hope this helps. Let me know if anything is unclear.
The formula for Kw is:
Kw= [H]*[OH]
where [H] and [OH] are
concentrations
We are given the pH so we can calculate the [H]
concentration from the formula:
pH=-log[H]
7.43 = -log[H]
[H] = 3.715x10^-8 M
In neutral solution, [H] = [OH], therefore:
<span>[OH]= 3.715x10^-8 M
Calculating Kw:
Kw = (3.715x10^-8)*( 3.715x10^-8)</span>
<span>Kw = 1.38 x 10^-15 </span>
Answer:
The pressure exerted by the buggy on the surface of Mars is 1600 pascals.
Explanation:
The pressure is determined by the definition of stress, which is the force exerted by the buggy on the martian surface divided by the contact area of the latter:

Where:
- Stress, measured in pascals.
- Force, measured in newtons.
- Area, measured in square meters.
The force is the weight of the buggy (40 N) and
, the stress is now calculated:


The pressure exerted by the buggy on the surface of Mars is 1600 pascals.
Given the molarity of the solution is
.
The volume of the solution is 10.9/1000 L
Number of moles of HCl = Molarity * volume of the solution in L
Number of moles of HCl =
*
Number of moles of HCl = 2.7 moles.
Therefore number of moles of HCl in 10.9 ml of the stomach acid is 2.7 moles