Upon heating a sample of NiCl2•6H2O, a sample originally weighing 3.5 g yields an anhydrous salt residue weighing 2.1g. What is the percent by mass of water in the hydrate?

Percent by mass = 40%

Explanation:

Mass of Compound before heating = 3.5g

Mass of compound after heating = 2.1g

Mass of water present = 3.5g - 2.1g = 1.4g

Percent by mass = ( Mass of water /  Mass of compound ) x 100

Percentage by mass = (1.4 / 3.5) x 100

Percent by mass = 0.4 x 100

Percent by mass = 40%

the answer is d : ) have a good da

a: 45.9 meters

b: 4.29 seconds

step-by-step explanation:

a: h(t)=1/2(-9.8)(3)^2+0(3)+90

h(t)=-4.9(3)^2+90

h(t)=-44.1+90

h(t)=45.9 meters

b: 0=1/2(-9.8)(t^2)+0t+90

0=-4.9t^2+90

-90=-4.9t^2

18.37=t^2

t=4.29 seconds

in the second question, the numbers aren't exact, but they're a close approximation.