The standard molar enthalpy of formation of NH3(g) is -45.9 kJ/mol. What is the enthalpy change if 9.51 g N 2(g) and 1.96 g H2(g) react to produce NH
3(8)?
a.-29.8 kJ/mol-rxn
b.-43.7 kJ/mol-rxn
C.-10.3 kJ/mol-rxn
d.-20.7 kJ/mol-rxn
e. -65.6 kJ/mol-rxn

Agood hypothesis includes which of the following? a: prediction b: data c: uncertainty d: conclusion

Two metal blocks that have slightly different temperatures are placed next to one another. after five minutes, they both have lower but equal temperatures. according to the law of conservation of energy, what  most likelyhappened? energy was created inside the blocks.energy was destroyed inside the blocks.energy was absorbed into the blocks from outside the system.energy was transferred from the warmer block to the cooler block.

What is a substance? a. a physical property of matter b. a chemical property of matter c. an element or compound that cannot be physically separated d. characteristics used to tell the difference between mixtures