Which of these equations is balanced? a. h2o+co > h2co3 b. 2nacl +h2so4 > na2so4 + 2hcl c. 2cao+ h2o > ca(oh)2 d. mn +fe > mns + fe

The equatin that is balanced is 2NaCl + H2SO4 → Na2SO4 + 2HCl. The answer is letter B. The reactant has two Na, 2 Cl, 2 H, 1 S and 4 O. These number of atoms is also the same for the product side.

electron microscopy and scanning tunneling microscopes gives us a greater understanding of atoms by being able to see the atom itself, and lets us see some atomic reactions.

explanation:

- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms