I got the answer +1300. However, they wanted it in sig figs. Would it be 1000?

Calculate the standard reaction enthalpy for the reaction between  

 

 

 

Compound
	-46
	-286
	34

 

 

 

Enter either a+ or - sign and the magnitude. Hint: Significant figures are determined by place value.

 

__________

What is the standard enthalpy of reaction for 2H2(g) + O2(g)-->2H20(g)?

please show calculations. When I did them I got +483kj/mol if O-H is 463kj/mol and H2 is 497kj/mol and O2 is 436kj/mol. the answer should be -483kj/mol however. The formula is reactant - products right?

Which of the following solutions is acidic?

A. [H30+] = 7.0x10^-7 M

B. [H3O+] = 1.5 x 10^-10 M

C. [H3O+] <7.0 X 10^-7 M

D. [H3O+] > 7.0 X 10^-7 M

E. [H3O+] = 1.0 X 10^-14

I attempted this by finding pH via the negative log of each H3O value.... which gives me a pH of 6.15 when [H3O+] is 7.0 x 10^-7 M. The way the question is worded is tricky however - it seems that only one answer is wanted (and all other questions in this assignment have only one answer) but technicially wouldn't a pH = 6.15 AND <6.15 both be acidic? and, potentially, couldnt a ph of >6.15 POSSIBLY be acidic as well if it were under 7?