Author Topic: I need help in chemi P1 PLZ!  (Read 1170 times)

Offline farahkuwait

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I need help in chemi P1 PLZ!
« on: May 25, 2010, 08:24:38 am »
Ok so i have to questions:
1- what is the relationship between: (barium nitrate+Hydrochloric acid) if theres any..
2- when volume of water increases, what happens to the temperature,, example:

15 When solid X is dissolved in water, an endothermic change takes place.
When 5 g of X are dissolved in 1000 cm3 of water, a temperature change of 10 °C occurs.
Which temperature change occurs when 5 g of X are dissolved in 500 cm3 of water?
A. a decrease of 20 °C
B. a decrease of 5 °C
C. an increase of 20 °C
D. an increase of 5 °C

??

Offline SoONa

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Re: I need help in chemi P1 PLZ!
« Reply #1 on: May 25, 2010, 10:23:39 am »
heyy .. i know the answer to the last question cuz i did it yesterday .. the answer is a decrease by 20.. cuz its endothermic so a decrease in temp and we halfed the conc. so doubled the temp.. ..
good luck

Offline Ghost Of Highbury

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Re: I need help in chemi P1 PLZ!
« Reply #2 on: May 25, 2010, 12:38:44 pm »
Ok so i have to questions:
1- what is the relationship between: (barium nitrate+Hydrochloric acid) if theres any..
2- when volume of water increases, what happens to the temperature,, example:

15 When solid X is dissolved in water, an endothermic change takes place.
When 5 g of X are dissolved in 1000 cm3 of water, a temperature change of 10 °C occurs.
Which temperature change occurs when 5 g of X are dissolved in 500 cm3 of water?
A. a decrease of 20 °C
B. a decrease of 5 °C
C. an increase of 20 °C
D. an increase of 5 °C

??


Barium nitrate + HCl = Barium Chloride + Nitric acid

Inversely proportional , volume of water decreases, more heat taken in.

(10*1000)/500 = 20

decreases by 20.

decreases because its endothermic.
divine intervention!