ocr a f325 revision thread

Original post by MathsNerd1

Erm, yeah that should be fine. Still only for 2 hours though.

Posted from TSR Mobile

OK you start :smile:

we do chapters 1 and 2 , for chapter 2 do pages 166-181

Reply 203

Original post by BeckyChatfield

Eugh I hate Chemistry so much!! Doing this paper, F322 AND F324 in the Summer!! Literally a case of ARGH!! Can't do Chem exams apparently!! At a D overall at the moment and need a B!! :frown:

I feel for you, I'm doing F321, F324 and this one as well for the summer, luckily I got a B in F322 so I won't be redoing that one but I need an A overall for my chosen university, we just need to work hard and hopefully it'll all pay off in the end :smile:

Reply 204

Original post by otrivine

OK you start :smile:

we do chapters 1 and 2 , for chapter 2 do pages 166-181

Okay let's build into like always.
Define lattice enthalpy and enthalpy change of atomisation. (4)

Posted from TSR Mobile

Reply 205

Original post by MathsNerd1

Okay let's build into like always.
Define lattice enthalpy and enthalpy change of atomisation. (4)

Posted from TSR Mobile

Lattice enthalpy is the energy that accompanies a reaction in which 1 mole of an ionic compound is formed from its gaseous ions under standard conditions.

Enthalpy change of atomisation is the enthalpy change that takes place when 1 mole of a gaseous atom is formed from the element under standard conditions.

Reply 206

Original post by otrivine

Lattice enthalpy is the energy that accompanies a reaction in which 1 mole of an ionic compound is formed from its gaseous ions under standard conditions.

Enthalpy change of atomisation is the enthalpy change that takes place when 1 mole of a gaseous atom is formed from the element under standard conditions.

Correct!

Posted from TSR Mobile

Reply 207

Original post by MathsNerd1

Correct!

Posted from TSR Mobile

Write an equation between nitric acid and limestone and is the reaction a redox? (4)

Reply 208

Original post by otrivine

Write an equation between nitric acid and limestone and is the reaction a redox? (4)

Okay the equation will be 2HNO3 + CaCO3 --> Ca(NO3)2 + H2O + CO2

And it isn't a redox equation? :s-smilie:

Reply 209

Original post by MathsNerd1

Okay the equation will be 2HNO3 + CaCO3 --> Ca(NO3)2 + H2O + CO2

And it isn't a redox equation? :s-smilie:

Yup correct!

my turn

Reply 210

ImageUploadedByStudent Room1364920217.324042.jpg84.4KB

Original post by otrivine

Yup correct!

my turn

That's a relief! And okay, question 1. (5)

Posted from TSR Mobile

(edited 11 years ago)

Reply 211

Original post by MathsNerd1

That's a relief! And okay, question 1. (5)

Posted from TSR Mobile

-57.5 , correct to 3 sig figure

Reply 212

Original post by otrivine

-57.5 , correct to 3 sig figure

Correct!

Posted from TSR Mobile

Reply 213

Original post by MathsNerd1

Correct!

Posted from TSR Mobile

Why is the value for enthalpy change of atomisation always positive (1)

Reply 214

Original post by otrivine

Why is the value for enthalpy change of atomisation always positive (1)

Because it is an endothermic process as the bonds have to be broken, hence the value is always positive.

Posted from TSR Mobile

Reply 215

Original post by MathsNerd1

Because it is an endothermic process as the bonds have to be broken, hence the value is always positive.

Posted from TSR Mobile

correct

my turn

Reply 216

ImageUploadedByStudent Room1364921108.638881.jpg103.7KB

Original post by otrivine

correct

my turn

Okay, here you go. (7)

Posted from TSR Mobile

Reply 217

Original post by MathsNerd1

Okay, here you go. (7)

Posted from TSR Mobile

2)a) 0.43 moles
b) Concentration of CH3COOH = 0.43 , Con of C2H5OH = 1.43 and concentration for the ester and water is 1.57

c) Kc= 4.01 , no units

Reply 218

Original post by otrivine

2)a) 0.43 moles
b) Concentration of CH3COOH = 0.43 , Con of C2H5OH = 1.43 and concentration for the ester and water is 1.57

c) Kc= 4.01 , no units

Except from part a you got it all right. The first part asked you how much of CH3COOH has reacted if 0.43 moles remained, so you'd do 2-0.43 to give 1.57 moles but other than that you were correct. :smile:

Reply 219

Original post by MathsNerd1

Except from part a you got it all right. The first part asked you how much of CH3COOH has reacted if 0.43 moles remained, so you'd do 2-0.43 to give 1.57 moles but other than that you were correct. :smile: