Lucinda

calculate the concentration of sodium benzoate that must be present in a 2.0M solution of benzoic acid (C6H5COOH) to produce a pH of 4.00. THIS IS THE ONLY INFORMATION GIVEN. I CANNOT FIND Kb ANY WHERE IN MY TEXT NOR DOES IT GIVE US A VOLUME. CAN ANYONE H...

15 years ago

What is the pH of a 2.62 x 10 -1 M HCN solution ? NB the pKa for HCN = 9.212. 4.90 9.21 0.58 11.32 13.42

15 years ago

An acid HA has Ka = 2.28 x 10 -4. The % ionisation of this acid in a 0.170 M solution of the acid in water is closest to 3.662 % 0.623 % 0.498 % 2.930 % 0.436 % 2.564 % i have an exam in 1 week and these are the types of questions i don't understand

15 years ago

What is the pH for the solution made from 11.10 mL of 0.278 M HCl solution mixed with 70.90 mL of 0.1300 M ammonia solution ? Note that the pKa for NH4+ is 9.241 8.94 9.24 8.77 9.72 9.54

15 years ago

In the analysis of food, the nitrogen from the protein is sometimes converted into ammonia which is titrated against a strong acid. Given that the final NH3 concentration (approximate) is 0.2M and that pKa for NH4+ is 9.2, choose the best indicator for su...

15 years ago

i have an exam friday and cant figure this question out! What is the pH of a 2.62 x 10 -1 M HCN solution ? NB the pKa for HCN = 9.212. 4.90 9.21 0.58 11.32 13.42

15 years ago

what is the pH of a 2.62x10^-1 M NaNO2 solution? NB the pKa for HCN=9.212 12.13 13.42 1.87 8.29 0.58 and also; what is the pH of a 2.62x10^-1 M HCN solution. NB the pKa forn HCN is 9.212. 4.90 9.21 0.58 11.32 13.42

15 years ago

I GOT THIS WRONG IN AN ASSIGNMENT. I HAVE AN EXAM IN 2 DAYS. CAN YOU SHOW ME HOW TO DO IT PLS. What is the pH of a 2.62 x 10 -1 M NaNO2 solution ? NB the pKa for HNO2 = 3.153. 12.13 13.42 1.87 8.29 0.58

15 years ago

1. You will need 600mL of a 0.5M NaOH solution. 3M NaOH is provided. Determine how much of the 3M NaOH you will need and write a procedure in your notebook for making the solution.

15 years ago

One characteristic of monomers that form addition polymers that is not common in monomers which form condensation polymers is: a. the presence of alkyl side chains b. the presence of two functional groups. c. the presence of pi bonds. d. None of the above...

15 years ago

Carboxylic acids are stronger acids than alcohols A. This is because the carboxy anion is delocalised. B. This is because the hydrogen atom is delocalised. C. The O-H bond in carboxylic acids is very strong. D. This statement is not true One characteristi...

15 years ago

A system loses 14.2 kJ of heat while performing 7.2kJ of work on the surroundings. If the initial internal energy, E, is 77.6 kJ, what is the final value of E? 56.2 kJ 70.6 kJ 99.0 kJ 84.6 kJ

15 years ago

Calculate the ƒ¢H‹ rxn for the following reaction. ƒ¢H‹ f [H2S(g)] = -21 kJ/mol; ƒ¢H‹ f [SO2(g)] = -297 kJ/mol; ƒ¢H‹ f [H2O(l)] = -285.8 kJ/mol; 2H2S(g) + SO2(g) ¨3S(s) + 2H2O(l) a. 232.6 kJ b. 910 kJ c. -232.6 kJ d. -910 kJ

15 years ago

1. What is the amount of oxalate in 2 mL of 0.035M solution? a) 7 ¡Á 10¨C2 mole b) 1.75 ¡Á 10¨C2 mole c) 7 ¡Á 10¨C5 mole d) 1.75 ¡Á 10¨C5 mole 2. Sodium oxalate may be prepared by titrating oxalic acid (C2H2O4) with sodium hydroxide, according to the equa...

15 years ago

1. The rate of a chemical reaction may be defined as: a) The speed at which a molecule travels from point A to point B. b) The change in concentration of reactants or products per unit time. c) The change in concentration of reactant divided by change in...

15 years ago

Use the given data at 298 K to calculate ¦¤G¡ã for the reaction 2NO(g) + 2H2(g) ¡ú N2(g) + 2H2O(g) Substance NO(g) H2(g) N2(g) H2O(g) ¦¤H¡ãf (kJ/mol) 90 0 0 -242 S¡ã(J/K¡¤mol) 211 131 192 189 a. -270 kJ b. -630 kJ c. -3.46 x 104 kJ d. -667 kJ

15 years ago

Use the following thermodynamic data at 298 K to determine the equilibrium constant at this temperature for the reaction of iron in steam to form hydrogen and iron(III) oxide. 2Fe(s) + 3H2O(g) 3H2(g) + Fe2O3(s) Substance Fe(s) H2O(g) H2(g) Fe2O3(s) ÄH°f (...

15 years ago

Calculate the reaction free energy of: H2(g) + I2(g) 2HI(g) when the concentrations are 0.026 mol L-1 (H2), 0.33 mol L-1 (I2), and 1.84 mol L-1 (HI), and the temperature is 700K. For this reaction Kc= 54 at 700 K. +11.6 kJ mol-1 0 kJ mol-1 -11.6 kJ mol-1...

15 years ago

I am struggling with how to answer this. It seems not enough information is given so it is really hard to agree or to disagree. (this is uni statistics) Assume you are the Store Manager for Coles in Wagga at the beginning of December 2012. An accountant i...

12 years ago

What are the parts of an exhaust system for a high bypass turbo fan and jet engine.

7 years ago

hemothorax is an accumulation of blood/fluid in the plueral cavity, ussually caused bt trauma. i would go with D. a good book every nurse should have, i do, is MOSBY'S DICTIONARY. ISBN: 0815148003 it's worth every cent!

15 years ago

the answer is in the question. the "radiopaque" would suggest xray/scans/ultrasounds...therefore the correct answer is D. angioplasty is surgery to correct/stablise vessels.

15 years ago

well, willy. Is it A or D. you are confusing me. i know that if you changed the question and swapped the addition and condensation around the answer is B.

15 years ago

gaby can you show me how you did this? i kept getting 333

15 years ago

i figured dH to = -664, the dS = -114. then i use equation> dG = dH -TdSand i got 333.08 kJ

15 years ago

not sure if this is right but... do you just square root it twice- giving 4.304cm. then wourk out the area? I don't have the picture so i'm assumming its a cube/square.

15 years ago

this is pretty much what i thought. and also being december with xmas shopping etc...sales should usually be high making a profit also...?? so many things not given in the question that really would determine and agree or a disagree. Thanks, wanted to mak...

12 years ago

9/24+4/24=13/24 24/24-13/24=11/24

7 years ago