Reef Chemistry Question of the Day #40 Water weight

[Randy Holmes-Farley]

Reef Chemistry Question of the Day #40

Compared to freshwater, the same volume of natural seawater weighs approximately:


A. 35% more
B. 3.5% more
C. 26% more
D. 2.6% more
E. 1.026% more
F. 1.020% more

Good luck!






















.

 

[Keithcorals]

I think it's C

 

[Acro76]

awww... i was wrong! Tricky question :bigsmile:

 

[DFW]

D. This reminds me of a joke that my father told more than once when I was a child: "Which is heavier - a pound of feathers, or a pound of rocks?"

 

[H2O]

It's D .. DFW both pounds r equal .. if all dollars in existence add up to 10.3 trilion how is the IRS missing 9 trilion how is the pentagon missing 2.5 trilion and how u owe China 19 trilion or how u pay off 19 trilion with 10.3

 

[Steven@]

B... final answer...lol

 

[RacingTiger03]

saltwater is more dense than freshwater. Given the same VOLUME (let's say 1Gallon of each) as the question asks, saltwater will always weigh more ...

Since we measure in specific gravity, my guess is going to be..
E!

 

[beaslbob]

d

2.6% more means the sg is 1.026

 

[psirex]

D

Freshwater weighs ~ 8.4 Saltwater weighs ~ 8.6.....
Per gallon

 

[tzsetzse]

Depends upon the location where the seawater is collected. Salinities and dissolved solids vary around the globe

 

[Randy Holmes-Farley]

Depends upon the location where the seawater is collected. Salinities and dissolved solids vary around the globe

True, but does it vary enough that more than one of the answers is correct?

 

[H2O]

True, but does it vary enough that more than one of the answers is correct?

.
Yes it will vary depending on temperature so its possible to see another answer other then D

 

[Randy Holmes-Farley]

.
Yes it will vary depending on temperature so its possible to see another answer other then D

I don't think there is any place in any normal ocean where any answer except the correct one applies. The others are all eithr brackish water, or water so saline that even the most saline parts of the Red Sea do not meet that measurement.

 

[tzsetzse]

Ok. Having taken all that into consideration, "D" is the CLOSEST answer but I believe it to actually be 2.5%

 

[Randy Holmes-Farley]

Ok. Having taken all that into consideration, "D" is the CLOSEST answer but I believe it to actually be 2.5%

Can you share your math?

As folks have mentioned, salinity varies considerably, but for 35 ppt seawater, one of the answers is exactly correct to within the number of significant figures given.

 

[leptang]

B is my guess, so normal seawater is 35ppt of salt thats 35 pounds per 1000 gallons of water

 

[beaslbob]

I thought the specific gravity was based on how dense the water is. therefore the same volume weighs that much more.

 

[chrisfraser05]

A definite D from me

 

[beaslbob]

Can you share your math?

As folks have mentioned, salinity varies considerably, but for 35 ppt seawater, one of the answers is exactly correct to within the number of significant figures given.

Hopefully he's throwing a curve here.

 

[beaslbob]

Otherwise I'm wrong.