Chemistry - September 2007

Which of the following are true statements ?

a) Water is a homogeneous mixture
b) Neon is an element
c) Mixing sand in water and allowing it to stand undisturbed for an
extended period of time will lead to a homogeneous mixture.
d) Magnesium chloride MgCl2 is a heterogeneous mixture

2007-09-06 12:35:17 · 1 answers · asked by Anonymous

Explain how the heat from the combustion reaction is related to the temperature change of the water.

2007-09-06 12:35:16 · 1 answers · asked by NaimFrasheri 1

A piece of lead having a mass of 104.5 g is placed in an empty graduated cylinder.
35.0 mL of water is then poured slowly and carefully into the same cylinder.The final water level would then indicate the total volume of the materials in the graduated cylinder.
What is this total volume in millileters

2007-09-06 12:34:38 · 1 answers · asked by Anonymous

16.7 pounds
34.3 pounds
167 pounds
343 pounds

2007-09-06 12:09:49 · 6 answers · asked by notachemwiz 1

which weighs 4.32 kg?

0.000625 cm3
0.625 cm3
1.60 cm3
1.60 L

2007-09-06 12:08:30 · 1 answers · asked by notachemwiz 1

Write the balanced equations for these solutions

A.) NaClO + (Na2S2O3 in NaOH) ---->

B.) NaClO + (KI in NaOH) ----->

C.) NaClO + (Na2SO3 in NaOH)

PLease list all the equations, balanced, because i have no idea what the products look like, since the second set of reactions are in sodium hydroxide.

2007-09-06 12:06:44 · 2 answers · asked by shashank 2

you have 2 distinct gaseous compunds made from elements x and y:
compund 1: 30.43%x, 69.57%y
compund 2: 63.64%x, 36.36%y

when you react gas x with y, you get:
1 volume gas x + 2 volumes gas y -> 2 volumes compund 1

2 volumes gas x + 1 volume gas y -> 2 volumes compund 2

Assume simplest possible formula and determine relative atomic masses of element x and element y.

i don't understand how to incorporate the percents.

2007-09-06 11:44:02 · 2 answers · asked by Anonymous

Question

The electrolysis of an unknown pure substance resulted in two separate components. The original sample is a(n) _______. The resulting substances can be __________ or _________.


a. heterogeneous mixture b. solution c. compound

d. element

2007-09-06 11:02:01 · 1 answers · asked by edge0125 1

How do enzymes effect the equilibrium constant?

2007-09-06 10:42:46 · 2 answers · asked by dfgh d 1

1M copper(ii) sulfate, a copper strip and a coin? I'm guessing the coin is made out of silver

2007-09-06 09:46:29 · 0 answers · asked by mrsjoshgroban 1

2007-09-06 09:38:48 · 2 answers · asked by lilak95 1

We put two wires attached to a 9 volt battery in a solution of water and household salt. The immediate effect was the forming of a small amount of white/grey substance off the wires, then the water turning slightly yellow. On settling the water is now colourless with a deposit of gold coloured mattered at the bottom of the glass. Could you give me a chemical equation of what has happened?

2007-09-06 09:33:37 · 2 answers · asked by Anonymous

Is it:

HNO3 + Zn0 ----> ZnNO3 + H2O?

2007-09-06 09:32:24 · 2 answers · asked by Anonymous

2007-09-06 09:29:32 · 5 answers · asked by Amanda M 1

I just dont understand what the things in the brackets meant. And then whats the difference?

2007-09-06 09:26:50 · 9 answers · asked by Anonymous

I need help relating these into one large equation:

V=3b P=(a/27b^2) T=(8a/27Rb)

2007-09-06 09:21:27 · 1 answers · asked by Kiss M 1

2007-09-06 09:17:31 · 5 answers · asked by magiccaster4 1

im doing my project on biochemistry but i dont know what it means.

2007-09-06 09:08:26 · 6 answers · asked by Anonymous

http://www.abington.k12.pa.us/zuckar/ban_dihydrogen_monoxide.htm

today was my first day of bio, 9th grade. my teacher gave us this website to read over, and discuss on monday. isn't dihydrogen monoxide water? from the way it's described, 'Most of these deaths are caused by accidental inhalation of DHMO, but the dangers of dihydrogen monoxide do not end there. Prolonged exposure to its solid form causes severe tissue damage' If you breathe in water, you'll drown, and if you are exposed to ice for a long time, you'll get frostbite.
So... am I right?

2007-09-06 09:01:55 · 4 answers · asked by cloulve 2

1.08 g of NaH2PO4 and 3.66 g of K2HPO4 are dissolved in sufficient water to make a liter of solution. Calculate the pH of the resulting solution.

2007-09-06 09:00:26 · 1 answers · asked by jon st. germain 1

Thank you in advance!

2007-09-06 08:58:20 · 1 answers · asked by Kate 1

2007-09-06 08:32:25 · 1 answers · asked by Anonymous

2007-09-06 08:03:59 · 9 answers · asked by mrk_ck 2

2007-09-06 08:00:09 · 4 answers · asked by Meggy 2

Look at it, it's not in any sensible shape. I asked one of my friends this question, and they said it is because there are spaces reserved for undiscovered elements. At this, I asked him how they know about these elements if they are undiscovered.

He didn't have an answer to this, maybe you do?

2007-09-06 07:55:18 · 3 answers · asked by Anonymous

I am given a compound. It is C3H2F2.. with the 3 carbons being double bonded to each other. The questions wants me to indicate the type of orbitals on each atom used to form each bond. I am not sure if I am right but I know the first and third carbon use sp2 orbitals to bond to hydrogen (s orbital) and fluorine (which I am not sure what orbital it is to bond to carbon). the middle carbon uses sp orbitals. I'm really confused as to what orbitals fluorine uses to bond to carbon and if the rest of my work is correctly done? please help!!

2007-09-06 07:41:59 · 3 answers · asked by vaflip 1

2007-09-06 07:28:10 · 2 answers · asked by John D 2

2007-09-06 07:20:02 · 5 answers · asked by rayg 1

What is the pH of a solution which contains 0.0516 moles of sodium acetate and 0.1204 moles of acetic acid?

acetic acid Ka = 1.8*10^-5

2007-09-06 06:56:02 · 1 answers · asked by jon st. germain 1

i need answers to these questions please!

1. Research chemists discovered a simple way to reduce the amount of harmful nitrogen oxide in car
exhaust fumes. If a stream of ammonia gas is injected into the hot exhaust, the following reaction
happens:
6NO(g) + 4NH3(g) ® 5N2(g) + 6H2O(g)
a) What are the products of this reaction?
b) How much ammonia, NH3, would be needed to react with 18g of nitrogen oxide, NO?
c) Assume that the average distance travelled by a car is about 19,800km per year, and that the
average car emits 1g of nitrogen oxide per km.
How much ammonia would be needed for one car in a year?
2. a) Balance the following equation:
Fe2O3(s) + ¼CO(g) ® ¼Fe(l) + ¼CO2(g)
b) Iron(III) oxide is reduced to iron in the blast furnace according to the equation completed in
part (a). How much iron(III) oxide is needed to produce 112g of iron?
c) How much iron can be made from 320 tonnes of iron(III) oxide?

2007-09-06 06:37:16 · 7 answers · asked by Anonymous