The answer is 0.50 mol. The number of moles of potassium bromide in the beaker will not change since there is no additional potassium bromide introduced to the solution. The molarity of potassium bromide, the number of moles of water, the volume of the water solvent and the volume of the solution will all change if water is added.
Answer:

Explanation:
We can use the formula for momentum to calculate the mass.

Methane CH
does not have ionic bonds. Because of the close value of electronegativity of the carbon and hydrogen atoms the electrons are shared forming covalent bonds.
Answer:
V = 331.13 mL of 50 by mass NO3 solution
Explanation:
∴ δ sln = 2.00 g/mL
∴ %m HNO3 = 50% = ( mass HNO3 / mass sln ) × 100
∴ V required sln = 500 mL
∴ δ HNO3 = 1.51 g/mL.......from literature
⇒ V sln = mass sln / δ sln = 500 mL
⇒ mass sln = (500 mL )×( 2 g/mL ) = 1000 g sln
⇒ mass HNO3 = ( 0.5 )×(1000 g) = 500 g HNO3
⇒ V HNO3 = ( 500 g HNO3 )×(ml HNO3/1.51 g ) = 331.13 mL