Determine if the following equations are balanced or unbalanced a. Zn + HCl> ZnCl 2 + H 2
b. 2Na + H 2 > 2NaH
c. Al + Fe 2 O 3 > Fe + Al 2 O 3
d. MgBr 2 + Cl 2 > MgCl 2 + Br 2
e. C 3 H 8 + O 2 > H 2 O + CO 2

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under a microscope, cancer cells may look very different from normal cells. they often have different sizes and some may be larger than normal while others are smaller. cancer cells are often abnormally shaped and the control centre of the cell (the nucleus) may have an abnormal appearance.

i think? ?

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.