Chemistry - January 2007

1.)__ Balanced equation for the combustion of B 2H 6
2.)__Neutralization of stomach acid (HCl) by milk of magnesia (magnesium hydroxide)
3.)__Balanced equation for the combustion of Si 4H 10
4.)__Thermal decomposition of nitrous oxide (laughing gas)
5.)__A salt like(alkaline earth metal) hydride reacting with water.
6.)__Thermal decomposition of witherite (barium carbonate)
7.)__Reduction of a metal halide by drogen to form a metal

a. CaH 2 + 2 H 2O --> Ca(OH) 2 + 2 H 2
b. PdCl 2 + H 2 --> Pd + 2 HCl
c. BaCO 3 --> BaO + CO 2
d. 2 HCl + Mg(OH) 2 --> MgCl 2 + 2 H 2O
e. B 2H 6 + 3 O 2 --> B 2O 3 + 3 H 2O
f. 2 Si 4H 10 + 13 O 2 --> 8 SiO 2 + 10 H 2O
g. NH 4NO 3 ---> N 2O + 2 H 2O

2007-01-28 14:07:17 · 6 answers · asked by Cupcake 2

This is in regards to DNA. Why would you say that it was a great find for scientists and how has it helped science in general?

2007-01-28 13:19:59 · 9 answers · asked by M. M 4

Thanks, I have some hw problems that I wasnt sure the anwer of, if u can explain it, that would help and if not its ok!

1. Choose the word that best completes the following statement. In a neutralization reaction an acid and base react to form water and ________________.

a.salt
b.metal
c.ionic compound
d.ester

2.Determine the mass of sodium chloride produced when 1.75 moles of chlorine gas reacts with sodium
a.202.64 g NaCl
b.204.54 g NaCl
c.188.53 g NaCl
d.244.02 g NaCl
e. 2.04 g NaCl

3.The [H+] of a solution is 1 x 10-4. What is the pH of the solution?
a.pH 10
b.pH 8
c.pH 4
d.pH 2

4. There are two answer choices that would correctly complete this sentence. Choose both answers. Antacids are bases. People use the antacids to __________________ the acids in the stomach.
a.buffer
b.increase the concentration of
c.neutralize
d.decrease the concentration of

2007-01-28 13:18:35 · 5 answers · asked by nice too meet you. 4

what is an activity series and how is it used in a single displacement? please give me an examples and real-life application if possible^^

2007-01-28 13:09:33 · 1 answers · asked by aebin 4

2007-01-28 12:59:57 · 2 answers · asked by ninekittys 3

2007-01-28 12:58:53 · 3 answers · asked by Anonymous

2007-01-28 12:57:57 · 2 answers · asked by eg4ever1 1

What are the oxidations sates of the transition metal ion in each of the following:
[Co(H20)6]^3+, [Cr(H2O)4(Cl)2], and [Os(NH3)2(Cl)2]SO4

Please help and explain!!!!

2007-01-28 12:42:36 · 5 answers · asked by Anonymous

Match the descriptions with the names and symbol/formula of a Group 5A(15) element/compound.

1.)__Element(s) essential in plant nutrition
2.)__Phosphorus-containing water softener
3.)__Hydride produced at multimillion-ton level
4.)__Hydride used to manufacture rocket propellants and drugs
5.)__Amphoteric hydroxide with a 5A element in its' +3 oxidation state
6.)__Two examples of an odd-electron molecule
7.)__Element that is an electrical conductor

a. ammonium, NH 3
b. nitrogen and phosphorus, N & P
c. hydrazine, N 2H 4
d. nitrogen monoxide and nitrogen dioxide, NO & NO 2
e. diarsenium trioxide, As 2O 3
f. sodium tripolyphosphate, Na 5P 3O 10
g. bismuth, Bi

2007-01-28 12:31:41 · 2 answers · asked by Cupcake 2

discribe the shape and give the bond angle of molecule CH4 methene

2007-01-28 12:30:29 · 3 answers · asked by Anonymous

2007-01-28 12:28:24 · 3 answers · asked by Anonymous

A 15-g sample of lithium is reacted with 15 g of fluorine to form lithium fluoride: 2Li + F2 --> 2LiF. After the reaction is complete, what will be present?

a.2.16 moles lithium fluoride only
b.0.789 moles lithium fluoride only
c.2.16 moles lithium fluoride and 0.395 moles fluorine
d.0.789 moles lithium fluoride and 1.37 moles lithium
e.none of these

2007-01-28 12:20:55 · 2 answers · asked by Anonymous

2007-01-28 12:19:56 · 5 answers · asked by stlouiscards8 3

My high school chemistry teacher told us about mixing some things and getting a solution that after drying on a surface (such as a driveway) would make loud cracks when walked on or driven over. This would be a great way to get back at some friends, but I cant remember what to mix to get this. Does anyone know?

2007-01-28 12:18:07 · 3 answers · asked by anonymous 2

i am making my schedule for my junior year
i have to drop one of the classes because of physics.
(There's no space if I add physics on my schedule)

So which one should I take for my junior year, chemistry AP
or Biology AP?

2007-01-28 12:08:38 · 9 answers · asked by Daine W 2

I am really sorry to ask this question but it's about science and it's my worst subject. I even googled and yahooed this question but weird answers came up, so can you please answer this question without giving me URL's and stuff..THANX

Why is silicon important?

What would happen if Silicon never existed?

PLEASE...I KNOW THESE MIGHT BE EZ QUESTIONS...but sorry I am not good at sciene so this was my only hope. :]

THANK YOUUUUUU!!!!!!!!!!!!!!!!!!!!!!!!!

2007-01-28 12:07:49 · 3 answers · asked by Miss Universe 2

2007-01-28 12:05:26 · 2 answers · asked by ashnadpersaud 1

what are the properties of the group?

2007-01-28 11:51:43 · 1 answers · asked by i<3mauro 2

What is the theoretical yield of silver chloride if 1.266g of calcium chloride are reacted w/ exces silver nitrate? Ans is 1.646g

i dont understand how they got this ans..so can somebody tell me how to do this prb thankz!

2007-01-28 11:48:33 · 2 answers · asked by pReCioUs_mE 1

A 15-g sample of lithium is reacted with 15 g of fluorine to form lithium fluoride: 2Li + F2 --> 2LiF. After the reaction is complete, what will be present?
I think I start by dividing 15 g by the molar masses, but is the molar mass
2 x amu of Li and 2 x amu of F?
Thanks

2007-01-28 11:45:16 · 2 answers · asked by Anonymous

I need help with this chem prb!!!
I know the ans. which is 9.400 but i dont understand how they got this ans. cant figure it out :(
can someone tell me how to do this prb thankz!

2007-01-28 11:42:18 · 1 answers · asked by pReCioUs_mE 1

Calculate the pH of a .700 M NaC2H3O2.
Ka (HC2H3O2)=1.8*10^-5

the answer is 9.29 but i dont know how it was solved by the packet

2007-01-28 11:33:07 · 4 answers · asked by Anonymous

Please only answer if you know what you're talking about. Why is Fluorine more reactive than Chlorine, for example?

2007-01-28 11:29:01 · 4 answers · asked by pinkcouture56 2

In doing an experiment, i found that mold wouldnt grow on Quaker breakfast cookies. I asked my biology teacher and he said that it had something to do with the preservatives in them. I found the preservative potassium sorbate in the breakfast cookies but can anyone tell me what it is doing so that mold won't grow on it???

2007-01-28 11:16:08 · 2 answers · asked by Sarah 2

2007-01-28 11:15:44 · 14 answers · asked by cylo1818 3

Could someone please explain this to me in laymans terms??? I don't understand it and I need to know it for my chem class.

2007-01-28 11:15:33 · 3 answers · asked by Amaya 3

CuSO4 +KI --> CuI + KI3 +K2S04

2007-01-28 11:11:11 · 3 answers · asked by perfectionistjc 2

What's the method to finding the answer?

2007-01-28 11:10:46 · 3 answers · asked by Travis 2

i have to complete this formula but i don't know how combustion works. please give me an ex.

2007-01-28 11:05:15 · 3 answers · asked by christine b 1

I know that the equation works, but I am interested in finding out whether that particular reaction would occur.

2007-01-28 10:48:40 · 1 answers · asked by Anonymous