Explanation:
balance the equation ...HCl,Ba(OH) and BaCl2 are aqueous
know groups of the elements H 1+ ,Cl -,Ba 2+,OH-
write complete ionic eqution and eliminate spectator ions those appearing on both sides Cl and Ba
Mass of metal piece is 611 g and volume of graduated cylinder is 25.1 mL. When metal piece is placed in the graduated cylinder water level increases to 56.7 mL. The increase in volume is due to volume of metal piece that gets added to the volume of water.
Thus, volume of metal piece can be calculated by subtracting initial volume from the final one.

Thus, volume of metal piece will be 31.6 mL. The mass of metal piece is given 611 g, density of metal can be calculated as follows:

Therefore, density of metal is 19.33 g/mL.
The lower the activation energy required for a chemical reaction
Answer: D (6.04) is the best answer
Explanation:
pOH = - log [OH⁻]
pOH = - log (9.0 x 10⁻⁷)
pOH = 6.0457