Answer:
B is False
Explanation:
In physical chemistry we always look from system's perspective, so if we heat something ΔH is positive and if the system gives heat out then ΔH is negative.
A. We have to give energy to benzene to evaporate it. Statement true.
B. If heat is absorbed then the enthalpy must be positive.
C. The heat is absorbed then ΔH is positive.
D. Usually for burning heat is exposed from system. So enthalpy is negative.
E. Obvious
Answer:
Na2B4O7 + H2SO4 + 5H2O → 4H3BO3 + Na2SO4
Explanation:
The unbalanced equation is given as;
Na2B4O7 + H2SO4(aq) + H2O → H3BO3(s) + Na2SO4(aq)
Balancing the equation of the reaction involves making sure the number of moles of elements in the reactants to be equal to the number of moles of the element of the products.
The balanced equation is given as;
Na2B4O7 + H2SO4 + 5H2O → 4H3BO3 + Na2SO4
Density is g/cm^3 so you get the volume of the block:
4.6×5.5×8.4= 212.52cm^3
Then you take grams÷cm^3:
Green and purple because they are non-metals or gases
Answer:
0.05 moles of sodium sulfate are required.
Explanation:
Concentration of sodium ions in 1 L = 0.10 M
Moles of sodium ions = 0.10 mol
1 mole of sodium sulfate gives 2 moles of sodium ions.
Then 0.10 mol of sodium ions will be given by:
0.05 moles of sodium sulfate are required.
