Na3PO4 + Ba(OH)2 --> Ba3(PO4)2 + NaOH How many moles of Ba3(PO4)2 will be formed if 400g of sodium phosphate is reacted?

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.

the answer is definitely c.

gas and precipitate r the correct answers