its 40
I just took the test right now to get this answer
Answer:
Se detailed explanation.
Explanation:
Hello,
In this case, since both magnesium and calcium ions are in group IIA, we can review the following similar properties:
- Since both calcium and magnesium are in group IIA they have two valence electrons, it means that the both of them have two electrons at their outer shells.
- They are highly soluble in water when forming ionic bonds with nonmetals such as those belonging to halogens and oxygen's family.
- Calcium has 18 electrons and magnesium 10 which are two less than the total protons (20 and 12 respectively) since the both of them have lost two electrons due their ionized form.
- Their electron configurations are:
It means that the both of them are at the 
region since it is the last subshell at which their electrons are.
Best regards.
First convert the 112 km/hr ratio into m/s (meters per second). To do this you multiply 112 km with 1000 m/km (since there's 1000 m in one km). You get 112000 m. Then multiply 1 hr with 60 min/hr (since there's 60 min in one hr. You get 60 min, but you want seconds, so multiply 60 min with 60 s/min to get 3600 s. There you go! Your answer is the speed of 112000m/3600s, but you can simplify that to 31.11m/s (since the answer should be in ? meters per 1 second.
Also, the "100-m-distance" part of the question is just to throw you off, because one particular speed obviously stays constant over any distance. Hope that helps :)
Solution:
At the equivalence point, moles NaOH = moles benzoic acid
HA + NaOH ==> NaA + H2O where HA is benzoic acid
At the equivalence point, all the benzoic acid ==> sodium benzoate
A^- + H2O ==> HA + OH- (again, A^- is the benzoate anion and HA is the weak acid benzoic acid)
Kb for benzoate = 1x10^-14/4.5x10^-4 = 2.22x10^-11
Kb = 2.22x10^-11 = [HA][OH-][A^-] = (x)(x)/0.150
x^2 = 3.33x10^-12
x = 1.8x10^-6 = [OH-]
pOH = -log [OH-] = 5.74
pH = 14 - pOH = 8.26
