Question

Does conservation always happen? Even with ice and water?

Answer 1

conservation of mass? yes, in chemical reactions, matter is neither created nor destroyed. water solidifies to ice and ice melts into water, same amount of atoms, always

Answer 2

A student does an experiment changing ice into water. The mass of the ice is 1Kg in the beginning. The student then heats it on a hotplate and the mass is now 0.8 kg. Why is the mass of the water that results lower than that of the initial ice? Where do you think that mass could have gone? Does conservation always apply?

Answer 3

it evaporated into a gas phase and floated away

Answer 4

Why is the mass of the water lower than the the initial ice?

Answer 5

because some of it evaporated and it escaped

Answer 6

Doesn't it have to do with density?

Answer 7

nope. ice is less dense than water, although so it occupies more volume with the same amount of mass. The mass remains the same whether it's ice, water, or water vapour.

Answer 8

what about conversions?

Answer 9

what about them?

Answer 10

you place a beaker with 60ml of a solution on a balance and finds its mass to be M60ml. However you only want to use 1.5 tsps of it and you want to know the mass of exactly how much you're using.

Answer 11

if there are 4.929 tsps in 1ml first convert 60 ml to how many tsps are in it

Answer 12

since you are using 1.5 divide 1.5 tsps by the total number of tsps to find the percentage

Answer 13

milliliters is not a unit of mass, but volume.

4.929 tsps = 1mL
60 mL = 295.74 tbps - 1.5 tbps = 294.24 tbps divide by 4.929 = 59.69 mL

so you need 0.304 mL

you can go about this conversion in several ways, you end up with the same answer.

Answer 14

what will the percentage be?

Answer 15

divide the volume you took, 0.304 mL, by the initial, 60 mL.

Answer 16

its 197.368

Answer 17

0.304/60= 0.0056 .. so it's 5.6%

Answer 18

ok i did it backwards .. thanks so much! that was extremely helpful

Answer 19

no prob!

Answer 20

so why is the mass of the water lower than the ice?

Answer 21

being put on a hot plate and heated raised it's kinetic energy and molecules bounced around and "escaped" from the liquid form into the vapour form, and we call this evaporating. That is the only way mass can be "lost", by mere transformation. It would certainly lose volume if it went from ice to water, like when you put water in the freezer and it expands, or a soda can (which is mostly water) and it explodes.

Answer 22

what about the 1.5 tspn part?