Chemistry - October 2007

C7H6O3 + CH3OH --> C8H8O3 + H2O

1st reactant = 1.50g Salicylic acid
2nd reactant = 11.20g Methanol
1st product = Aspirin
2nd product = Water
Experimental Yield is 1.27g

What is the theoretical yield?
What is the yield percent?

Please help me out ive been trying to figure this out for the last hour... Thanks

2007-10-28 09:03:53 · 1 answers · asked by jamet002 2

Fe(NO3)3 + KSCN ===> ???????

2007-10-28 09:02:25 · 1 answers · asked by Anonymous

2007-10-28 08:53:36 · 2 answers · asked by BARBARA K 1

So how do you explain a change of smell chemical reaction?
Amonia nitrate + sodium hydroxid==> ammonia hydroxide + sodium sulfate

a change of smell is the change that occurs but HOW does it happen? I need to explain it

2007-10-28 08:50:41 · 1 answers · asked by Anonymous

Potassiums average atomic mass is 39.10. K40 has a very low natural abundnce.

2007-10-28 08:48:13 · 1 answers · asked by Jackie D 1

Also why is I(-) a better nucleophile than F(-) in protic solvents?

2007-10-28 08:46:35 · 1 answers · asked by Anonymous

the subscript contains the mass number, right? what about the superscript?

2007-10-28 08:34:37 · 2 answers · asked by thru_irish_eyes105 1

How is it possible to weigh water when you need a container to put it in to weigh it, wont the container throw off the end value? roflz

2007-10-28 08:30:10 · 2 answers · asked by Anonymous

A 30.6 g sample of gas occupies 22.4 L at STP. What is the molecular weight of this gas? Please include sig figs, and thank you!

2007-10-28 08:25:49 · 2 answers · asked by Anonymous

What is the balanced net ionic equation for concentrated hydrochloric acid (HCl (is it aqueous????)) that is added to a solution of sodium carbonate (Na2CO3)?

2007-10-28 08:18:08 · 3 answers · asked by Anonymous

please help if u know biology!! give good details please

2007-10-28 08:17:28 · 2 answers · asked by Hannah L 1

2007-10-28 08:04:09 · 5 answers · asked by Konamauri L 1

=]

2007-10-28 07:59:52 · 3 answers · asked by Chuby 3

okay, im having a lot of trouble figuring out the answer to these two questions. ive looked thru my book a number of times and can never find the exact help i need.

first question.
liquid hydrogen peroxide, an oxidizing agent in many rocket fuel mixtures, release oxygen gas on decomposition:
2H202(l) ----> 2h20(l)+o2(g) = -196.1kj

how much heat is released when 647 kg of h202 decomposes?

and the next question is
silver chloride agcl precipitates when solutions of silver nitrate, AgNO3, and sodium chlloride NaCl are mixed.

to determine the molar heat of reaction for this precipitation, 100.0ml of 0.400 M silver nitrate and 50.0mL of .800M sodium chloride were mixed in a constant-pressure calorimeter, which has a negligible heat capacity. the temp of the mixture rose from 21.15*C to 25.55*C. if the density of the solution is 1.0g/ml and its specific heat is 4.18j/g*c, what is the molar heat of reaction for this precipitation.

thanks. please show how to do them, soo ic an learn.

2007-10-28 07:55:04 · 1 answers · asked by ilikegcalot 1

How can water be softened and what are the health concerns regarding chemically softened water?

2007-10-28 07:52:24 · 3 answers · asked by Anonymous

I need this for my science Project heh. I'd appreciate the help thanks

2007-10-28 07:49:44 · 2 answers · asked by sk8terpimpo33 1

Please provide some resources stating dangerous gold compounds.

2007-10-28 07:43:09 · 3 answers · asked by Chinki C 1

Adipic acid is used in the manufacture of nylon. The composition of the acid is 49.3% C, 6.9% H, 43.8% O (by mass) and the molecular weight is 146 amu. What is the molecular formula?

Please please help me with this. Thanks in advance!

2007-10-28 07:27:29 · 4 answers · asked by jamet002 2

and Do the fructose can move in TLC (sol. n-Butanol:acetic acid :watwr =4:1:1)

2007-10-28 07:07:21 · 1 answers · asked by Anonymous

what is the difference between the endpoint and the equivalence point of a titration???

2007-10-28 07:01:19 · 1 answers · asked by NEEDs MATH HELP!! 1

state whether you think they are good or bad please

2007-10-28 06:54:36 · 1 answers · asked by greenpink413 2

What is the internal energy change for the system if 883 joules of heat flows FROM the system into the surroundings and 365 joules of work is DONE on the system by the surroundings?

my answer was this, but the system where we submit our answers tells me that it's wrong!!

delta u = q + w
= 883 + (-365)
= 518 J

isn't that correct???

2007-10-28 06:33:50 · 2 answers · asked by Curious 1

A bomb calorimeter has a heat capacity of 843 J/°C and contains 473 g of water. If the combustion of 0.500 mole of a hydrocarbon increases the temperature of the calorimeter from 22.73°C to 26.95°C, determine the heat evolved per mole of hydrocarbon.

A. 8.38 kJ
B. 23.8 kJ
C. 76.0 kJ
D. 95.9 kJ
E. 8380 kJ

2007-10-28 06:30:37 · 3 answers · asked by desigoddess217 1

2007-10-28 06:21:06 · 1 answers · asked by Maggie 1

Why did we use a glowing splint instead of a burning splint?
The experiment was to place 5mL of hydrogen peroxide, in a test tube. Add a pinch of manganese dioxide. And test the gas that is given off with the glowing splint.

What gas were we testing for with the glowing splint? Oxygen?

2007-10-28 06:13:14 · 5 answers · asked by tooooodles 3

Here's the info I have:
.4063 g KHP
Titrated 17.93 mL of NaOH into the KHP solution
Mole ratio KHP:NaOH, 1:1

10 mL H2SO4
Titrated 26.39 mL NaOH into the acid
Mole ratio NaOH:H2SO4 is 2:1

Please help me!

Part 1 - Standardization
1. Calculate the moles of KHP from mass weighed out.
2. Calculate the moles of NaOH that would react with the KHP.
3. Calculate the concentration of NaOH using titration volume.

Part 2 - Titration of Acid
1. Calculate the moles of NaOH delivered from buret
2. Calculate the moles of acid that would react with the NaOH
3. Calculate the concentration of acid using sample volume.

2007-10-28 06:12:30 · 2 answers · asked by Anonymous

please explain this to me, b/c i can't remember it and i don't have my book with me! thanks!

2007-10-28 06:08:23 · 3 answers · asked by Anonymous

what are the steps to find the heat released in this problem?
and is the formula q=mc(deltaT)

36.0g of steam at 100.0degrees celcius(sp?) was condensed to water and cooled to 25.0degrees celcius(sp?). Find the heat released.

2007-10-28 06:05:18 · 2 answers · asked by Anonymous

A bomb calorimeter has a heat capacity of 843 J/°C and contains 473 g of water. If the combustion of 0.500 mole of a hydrocarbon increases the temperature of the calorimeter from 22.73°C to 26.95°C, determine the heat evolved per mole of hydrocarbon.

A. 8.38 kJ
B. 23.8 kJ
C. 76.0 kJ
D. 95.9 kJ
E. 8380 kJ


Can someone just Explain the steps?

2007-10-28 06:02:09 · 1 answers · asked by Anonymous

What is the enthalpy change when 22.5 g of CH4 are burned in excess O2?
CH4(g) + 2O2(g) ------>CO2(g) + 2H2O(l) DH°= -890 kJ

A. -39.5 kJ
B. -890 kJ
C. -1250 kJ
D. +890 kJ
E. +1250 kJ
no need to solve, How do you know?

2007-10-28 06:01:12 · 1 answers · asked by Anonymous