<span>Balancing the choices, we have as follows:
A. 3AgBr + GaPO4 → Ag3PO4 +GaBr3
B. 3H2SO4 + 2B(OH)3 → B2(SO4)3 + 6H2O
C. Fe + 2AgNO3 → Fe(NO3)2 + 2Ag
D. C2H4O2 +2O2 → 2CO2 + 2H2O
Therefore, the correct answers are option A and B. Hope this answers the question. Have a nice day.</span>
Answer:
b) 
The confidence interval for this case is given (6.21, 6.59)
So we can conclude at 95% of confidence that the true mean for the PH concentration is between 6.21 and 6.59 moles per liter
c) Since the confidence interval not contains the value 7 we reject the hypothesis that the true mean is equal to 7. And the same result was obtained with the t test for the true mean.
Explanation:
We assume that part a is test the claim. And we can conduct the following hypothesis test:
Null hypothesis: 
Alternative hypothesis 
The statistic is to check this hypothesi is given by:

We know the following info from the problem:

Replacing we got:

And the p value would be:

Since the p value is very low compared to the significance assumed of 0.05 we have enough evidence to reject the null hypothesis that the true mean is equal to 7 moles/liter
Part b
The confidence interval is given by:

The confidence interval for this case is given (6.21, 6.59)
So we can conclude at 95% of confidence that the true mean for the PH concentration is between 6.21 and 6.59 moles per liter
Part c
Since the confidence interval not contains the value 7 we reject the hypothesis that the true mean is equal to 7. And the same result was obtained with the t test for the true mean.
The purpose<span> of preparing </span>Set-up<span> _ is to act as a </span>control set-up<span> to ensure that the (measured variable) is only caused by the(changed variable) and not any other variables in the experiment.</span>
In order to synthesize a complex organic molecule, the
chemist should at least illustrate or imagine the bonds that are in need to be
cut down or to separate in order to obtain the compound that can be easily
changed.
Mass =70 ( Mass of protons=1 ,Mass of neutrons =1, Mass of electron =0.0005(can be ignored))
Therefore, 40 +30=70
Charge= -2 ( it is taking in/attracting electrons to its shell) base on the proton number you are able to identify if it is attracting or releasing an electron, if the electron number is more than proton number then it is attracting therefore resulting in a negative charge vice versa for releasing an electron.