Predictions for Chemistry 2014 HSC? (8 Viewers)

[faisalabdul16]

Is it U-238

Yeap

New question any one else?

 

[enigma_1]

Yeap

New question any one else?

yay, you go

 

[Queenroot]

Why do combustion reactions need monitoring?

 

[seventhroot]

Why do combustion reactions need monitoring?

so they don't combust too much

 

[faisalabdul16]

A student decomposed solid copper(II) nitrate, producing NO2(g) according to the following equation.
2Cu(NO3)2 (s) 2CuO (s) + 4NO2 (g) + O2 (g)

They bubbled the NO2 (g) into water in order to convert it into nitrous and nitric acid:

2NO2 (g) + H2O (l) HNO2 (aq) + HNO3 (aq)

To answer this question, assume that all of the NO2 produced by the student reacted with water.

(a) Calculate the volume of NO2 gas (measured at 25 0C and 100 kPa) produced by the decomposition of 0.75 g of solid Cu(NO3)2.

(b) The student trapped all of the NO2 gas in a beaker containing 100 mL of water, converting it to nitrous and nitric acids, as shown above. Calculate the pH of the resulting solutions.

Blue looks pretty cool.

 

[enigma_1]

so they don't combust too much

Not sure if serious

 

[seventhroot]

Not sure if serious

can confirm srs

 

[Queenroot]

so they don't combust too much

B6 bruh

 

[faisalabdul16]

can confirm srs

Someone do my question

 

[seventhroot]

B6 bruh

knew it

possible state rank?

Someone do my question

okay

A student decomposed solid copper(II) nitrate, producing NO2(g) according to the following equation.
2Cu(NO3)2 (s) 2CuO (s) + 4NO2 (g) + O2 (g)

They bubbled the NO2 (g) into water in order to convert it into nitrous and nitric acid:

2NO2 (g) + H2O (l) HNO2 (aq) + HNO3 (aq)

To answer this question, assume that all of the NO2 produced by the student reacted with water.

(a) Calculate the volume of NO2 gas (measured at 25 0C and 100 kPa) produced by the decomposition of 0.75 g of solid Cu(NO3)2.

~14 + 2x16 = 46

(b) The student trapped all of the NO2 gas in a beaker containing 100 mL of water, converting it to nitrous and nitric acids, as shown above. Calculate the pH of the resulting solutions.

pH = ln(106.5) = 4.6

an attempt was made.jpg

 

[Queenroot]

knew it

possible state rank?


okay


~14 + 2x16 = 46


pH = ln(106.5) = 4.6

an attempt was made.jpg

Lel that is what I do in my math exams

 

[seventhroot]

Lel that is what I do in my math exams

so roughly how much marks will I get for that? like make 2-3/3?

 

[Queenroot]

so roughly how much marks will I get for that? like make 2-3/3?

0

 

[seventhroot]

0

so the question wasn't worth any marks? ahh I see

 

[faisalabdul16]

knew it

possible state rank?


okay


~14 + 2x16 = 46


pH = ln(106.5) = 4.6

an attempt was made.jpg

Completely wrong.

so roughly how much marks will I get for that? like make 2-3/3?

0. Can't even give you pity marks.

0

so the question wasn't worth any marks? ahh I see

Question was worth 4 marks.

 

[MrBeefJerky]

Industrial Chem Q: Why are the large volumes of CO2(g) produced during the Solvay process of little environmental concern? Include chemical equations in your answer (3)

 

[faisalabdul16]

Industrial Chem Q: Why are the large volumes of CO2(g) produced during the Solvay process of little environmental concern? Include chemical equations in your answer (3)

The large volumes of carbon dioxide produced during the Solvay process are of little environmental concern as it is regenerated and re-used. In step of one of the Solvay Process, Calcium carbonate is heated in the kiln, producing calcium oxide (used in a later process) and carbon dioxide used in the next step.
In the second step, ammonia is saturated with brine forming sodium hydrogen carbonate as carbon dioxide is pumped in. Ammonia is added to brine forming ammonical brine and carbon dioxide is dissolved in (it is carbonated now). Sodium hydrogen carbonate and ammonium chloride are formed, and sodium hydrogen carbonate is separated through cooling the mixture to 0 degrees, and because of sodium hydrogen carbonates low solubility, it crystallises out.
In the third step, sodium hydrogen carbonate undergoes decomposition to not only form the sodium carbonate which is then sold to factories, but also carbon dioxide which is channeled back into the Solvay Tower to again be used and make sodium hydrogen carbonate. Hence because carbon dioxide is re-used, it is of little environmental concern as large volumes do not escape into the environment.

Equations are obvious, I'm too lazy to put them in.

 

[faisalabdul16]

Industrial Question - Explain the cleaning action of soap in terms of its molecular structure. 3 marks
Core Question - Describe two possible sources of contamination in a catchment, and assess methods that could be used for purifying the water before it reaches the town. 7 marks

 

[faisalabdul16]

bump

 

[faisalabdul16]

Industrial Question - Explain the cleaning action of soap in terms of its molecular structure. 3 marks
Core Question - Describe two possible sources of contamination in a catchment, and assess methods that could be used for purifying the water before it reaches the town. 7 marks

Is everyone asleep or something? -.- hahahaha

Industrial Question - Soap is an effective surfactant due to its unique tadpole-like structure which allows for two-pronged cleaning effects. Soap has a long hydrocarbon tail which is hydrophobic (water hating) and an anionic head which is hydrophilic (water loving.) By working together, soap is able to act as a bridge, carrying off particles as the tail attaches to oil droplets and as the head dissolves in water. By effectively encircling these oil particles, a micelle is formed. The micelle carries a negative charge, thereby making it unable to resettle on the surface of the water as the particles repel one another. Non-oily substances can also be removed as the head dissolves in the water, and the tail sticks in the air, thereby breaking the surface tension. This causes the particles to become more "wet" and thus wash off.