Chemistry - November 2007

2007-11-15 03:40:59 · 1 answers · asked by Chem 111 1

2007-11-15 03:39:47 · 3 answers · asked by Chem 111 1

An amount of Chlorine gas weighs 5.67g and reacts with 8.90 g Oxygen to form a compound. What is the empirical formula?

Ok is the stuff with the grams there to throw me off? Isn't the empirical formula just Cl2O? What's with this question?

2007-11-15 03:36:40 · 1 answers · asked by Burnt Toast 1

resulting mass is 0.546g.the cobalt is isolated and weighs 0.248g.what is the formula of the hydrate?
A)DETERMINE the number of moles of water lost from the hydrated unkown
B)DETERMINE the number of moles of cobalt collected
C)DETERMINE the number of moles of chloride in the compound
d)What is the mole ratio of cobalt to chloride(cobalt is equal to 1: )
E)WHAT is the mole ratio of cobalt to water lost (set cobalt to 1: )

2007-11-15 03:10:11 · 1 answers · asked by mohjd s 1

2007-11-15 02:50:31 · 1 answers · asked by Christina S 1

Still not getting it.

The combustion of 2.209 grams of elmonane, a hydrocarbon with a molar mass of 218.00 grams/mole, released 44.31 kJ of heat energy. What is the molar heat of combustion for elmonane (kJ/mol)?

For this I worked it out as:
2.209/218= 0.0101mol E (E for elmonane)
44.31/.0101 = 4387.13

But my answer is wrong. What am I supposed to be doing? And what is the right answer?

2007-11-15 02:44:52 · 2 answers · asked by Smoke20 1

Assume density of solution is 1.0

What volume of concentrated hydrochloric acid is needed to neutralize this amount of sodium hydroxide solution?

2007-11-15 02:44:11 · 3 answers · asked by Anonymous

This is a sample question, but I need to know how to figure it for later questions, can anyone help?

The synthesis of 16.10 grams of sterlingite, an organic compound with a molar mass of 109.42 grams/mole, absorbed 28.46 kJ of heat energy. What is the molar heat of formation for sterlingite (kJ/mol)?

2007-11-15 02:22:07 · 1 answers · asked by Smoke20 1

What is the coefficient for NO2

2007-11-15 02:20:08 · 1 answers · asked by bubba 1 1

assume no heat is lost to surroundings ; d of water is 1.00g/ml
I would appreciaste any help learning how to work these problems, even with a different prob set up thank you, I have a serious problem with setting these up

2007-11-14 22:40:07 · 1 answers · asked by HisGlory 1

if you could design a fireworks display, what salts would you use and why?
where do you observe colorful light emissions? what do they have in common?

2007-11-14 22:11:20 · 2 answers · asked by kris 1

2007-11-14 18:28:18 · 4 answers · asked by Shashi Ranjan 2

2007-11-14 17:51:20 · 4 answers · asked by Anonymous

I have a benzene ring with a -CO2CH3 (ester) at position one, and a -NO2 group at position three and five...is this more polar or less polar compared to:
a benzene ring with only the -CO2CH3 group
and a benzene ring with the -CO2CH3 group and one NO2
group at the third position?

2007-11-14 17:40:45 · 1 answers · asked by xsxplayboixsx 1

Determine the number of moles of Krypton contained in a 3.25 liter gas tank at 5.80 atm and 25.5 °C.
If the gas is Oxygen instead of Krypton; will the answer be the same? Why or why not?


I'm pretty sure the equation n=PV/RT should be used in this problem. All the information is given for it except for R, which is a constant, that can change.... confusing.

2007-11-14 17:28:51 · 4 answers · asked by Anonymous

Can sublimination be used in the project to isolate a particular soil compound?

While the soil compound possibly contains CuCl2, CoSO4, NiCl2 Biphenyl, Benzoic acid, Camphor , m-Nitroaniline and Napthalene.

How does the boiling point and the melting point of these compound tells you rather sublimination can be use or not?

2007-11-14 17:10:08 · 1 answers · asked by Anonymous

if converting from grams to moles 5 grams of ( 4 C3 H5 N3 O9) (4 being the co-efficent) what are the moles. I forgot how to do simple stuff when you multiply 5(1 mol / molecular mass) do you multiply it by 4? in other words do you do 5(1 mol/ 227.1) or 5(1 mol/908.4) , because of the coefficent. Please i need an answer asap. this is a small step in a half hour problem that goes a long way. Seem to have forgotten my basics.

2007-11-14 16:58:17 · 4 answers · asked by Protons 2

I need to make a bath of it and am rusty on my chemistry.

2007-11-14 16:50:47 · 4 answers · asked by toaddozer 3

Mixtures of helium and oxygen are used in scuba diving tanks to help prevent the bends, which is a condition caused by nitrogen bubbles forming in the bloodstream. If 95 L of oxygen and 25 L of helium at STP are pumped into a scuba tank with a volume of 8.0 L, what is the partial pressure of each gas in the tank and what is the total pressure in the tank at 25°C?

2007-11-14 16:40:32 · 1 answers · asked by sovietwarhawk 1

In a study of the properties of an aquoous solution of Th(NO3)4 a freezing point depression of 0.0703K was observed for an aqueous solution of molality 9.6 mmol kg^-1 What is the apparent number of ions per formula unit?

2007-11-14 16:33:51 · 5 answers · asked by ShouldBeSleeping 2

solution? Please help

2007-11-14 16:18:29 · 2 answers · asked by Tonie M 1

5) Potassium carbonate + bromine -----> potassium bromide +potassium bromate + carbon dioxide

2007-11-14 15:57:09 · 3 answers · asked by Caramel 2

2007-11-14 15:49:49 · 5 answers · asked by brooklyn15290 1

What is the speed of an electromagnetic wave having a frequency of 1.33 x (10 to the 17th power) Hz and a wavelength of 2.25 nm? Isn't it supposed to be 3 x (10 to the 8th power)? Please help and thanks :)

2007-11-14 15:40:32 · 4 answers · asked by R3B3LL10N 1

I am not sure what to do for most of them so could you help me?

1.Metals usually react to form cations [T/F]
2.Weak acids and bases are used ti wash clothes[T/F]
3.Acid precipitation results mainly from combustion reactions[T/F]
4.arrangement of elements with similar chemical properties in the periodic table. _____
5.Type of ion that is usaully formed by metal atoms.________
6.group of atoms with a net charge; the atoms are joined by covalent bonds.________
7.type of bond formed when a pair of electrons is shared
8.Phosphorus atom has___valence electrons
9.An example of an anion with the same number of electrons as Ne is________.

Help is appreciated ^-^

2007-11-14 15:09:17 · 3 answers · asked by Good Evening, Miss 3

2007-11-14 14:57:57 · 1 answers · asked by Anonymous

a gaseous element is a poor conductor of heat and electricity, and is extremely nonreactive. Is the element likely to be a metal, nonmetal, or metalloid?
where would the element be located on the periodic table?
Explain please!!

2007-11-14 14:55:34 · 3 answers · asked by Anonymous

2007-11-14 14:55:01 · 5 answers · asked by sojo3 1

2007-11-14 14:52:16 · 2 answers · asked by Help 1

Hvap for the liquid is 40.2 kJ mol-1 at 89°C.

2007-11-14 14:50:18 · 1 answers · asked by Sean D 2