Chemistry - October 2007

To find the mass percent of dolomite [CaMg(CO3)2] in a soil sample, a geochemist titrates 11.30 g of soil with 35.90 mL of 0.2516 M HCl. What is the mass percent of dolomite in the soil?
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2007-10-08 05:21:12 · 2 answers · asked by bumblebee 4

A mixture of KClO3 and KCl with a mass of 0.915 g was heated to produce O2. After heating, the mass of residue was 0.614 g. Assuming all the KClO3 decomposed to KCl and O2, calculate the mass percent of KClO3 in the original mixture.
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2007-10-08 05:20:10 · 2 answers · asked by bumblebee 4

Which of the following is true of he ionization energy of the elements?




a. ionization energy generally decreases as we move left to right and decreases as we move top to bottom in the periodic table

b. ionization energy generally decreases as we move left to right and increases as we move top to bottom in the periodic table

c. ionization energy generally increases as we move left to right and decreases as we move top to bottom in the periodic table

d. ionization energy generally increases as we move left to right and increases as we move top to bottom in the periodic table

2007-10-08 04:18:06 · 2 answers · asked by ee101202 1

!!!!!!!!!!please its home work!!!!!!!!!!!!

2007-10-08 04:13:33 · 10 answers · asked by Anonymous

2007-10-08 03:04:30 · 3 answers · asked by kz j 1

2007-10-08 02:02:36 · 1 answers · asked by michaelpc12 2

1) Lemon juice
2) Tomato juice
3) Apple juice
4) Washing soda solution

I need the exact color.

2007-10-08 01:38:43 · 2 answers · asked by Akilesh - Internet Undertaker 7

2007-10-08 01:35:44 · 2 answers · asked by quratulain h 1

Since some people say that aluminum is a cause of alzheimers disease, I know many people won't use deoderants any more that contain aluminum. Also since heating plastic has been known to have dangerous cancer causing fumes, what about heating aluminum pans in the oven?? Could aluminum give off anything (fumes, chemicals, etc) when heated to high temperatures?

2007-10-07 21:09:48 · 2 answers · asked by Wintergirl 5

What is the pH of a 0.10 M solution of NH4NO2? Ka for HNO2 = 4.6 10-4, Kb for NH3 = 1.8 10-5 (hint: consider the equilibrium NH4+ + NO2- NH3 + HNO2)

a)6.30
b)2.26
c)9.26
d)2.17

2007-10-07 20:20:32 · 1 answers · asked by Anonymous

2007-10-07 18:27:50 · 4 answers · asked by Anonymous

The equilibrium constant for the reaction:

H2 + I2 = 2HI

has a value of 50.0 at 745K.

When 1 mol I2 and 3 mol H2 are allowed to come to equilibrium at 745K in a flask of volume 10L, what amount in moles of HI will be produced?

2007-10-07 17:46:25 · 2 answers · asked by Peter G 3

What is the Lowest Percent for Isopropyl Alcohol? I know that there is a 99% and a 70% and a 50%, but I want to know if there is any percentage that is lower than 50%.

2007-10-07 17:24:57 · 4 answers · asked by darklinkredlink 2

2007-10-07 17:19:52 · 7 answers · asked by Royal 4

The catalytic decomposition of hydrogen peroxide can be expressed as:

2H2O2(aq) --> 2H2O(l) + O2(g)

A trial of this decomposition experiment produced the following data:


Volume of O2 produced at room conditions 240 ml
Barometric pressure 740 torr
Temperature of water 24oC
Temperature of O2 25oC
Vapor Pressure due to water at 24oC 22.4 torr


Calculate the volume of O2(g) produced at standard conditions of temperature and pressure. (enter your answer in liters)

2007-10-07 17:06:18 · 2 answers · asked by newtype603 2

If electricity is the movement of free electrons across a conductor. Does the conductor or element (such as copper) change since it's losing electrons? or does the atom create more electrons on it's own? I'm thinking that the electricity cycles in a loop which means that the electrons are constantly returning to it's original atom. But when you get arc's or when a power line is cut and the loop is severed, how do the atoms get their electrons back?

2007-10-07 16:47:28 · 2 answers · asked by Top Gun 1

2007-10-07 16:25:15 · 1 answers · asked by essence_05 3

(b) CuBr2 (aq) + NaOH (aq) ? (net ionic equation)

(c) AgNO3 (aq) + KI (aq) ? (net ionic equation)

2007-10-07 16:24:36 · 2 answers · asked by Circuiteer 1

what do elements in the same period have in common?

How can one find the number of valence electrons for elements?
Ex: find the number of valence electrons for element F?

2007-10-07 16:12:23 · 4 answers · asked by Wii 2

2007-10-07 16:11:07 · 3 answers · asked by Gideon 1

The answers given are the following:
a. 35
b. 1.12
c. 25.8
d. 62.4
e. 39.3

2007-10-07 16:04:40 · 4 answers · asked by Anonymous

A) density
B) concentration
C) temperature
D) mass
E) pressure


I thought that density mass and pressure were not intensive but I can only choose one, so i'm stuck?

2007-10-07 14:46:48 · 1 answers · asked by Anonymous

Two rain storms occurred in one week in a certain area. In the first rainstorm 25ML of rain fell per hour, and in the second rainfall 40ML of rain fell per hour. RAin fell that week for a total of 70 hours for a total rainfall of 2200ML. How long was each of the two rainstorms?

2007-10-07 14:33:41 · 1 answers · asked by rebeccapolsh333 2

i saw it in the answer to a chemistry question about dissolving Teo2 in SiO2- supposedly you can do that by dissolving the TeO2 in H2SO4, then doing a base wash- what's this mean tho?

2007-10-07 14:11:05 · 2 answers · asked by Pkizzle 2

When NaOH(aq) and CaCO3(aq) are mixed what recipitate forms and what color

same question with
NaOH and KCl
NaOH and K2CrO4
CaCO3 And KCl
CaCO3 and AgNO3
CaCO3 And K2CrO4
KCl And K2CrO4
AgNO3 and K2CrO4

I am having trouble making my table of knowns for a qualitative analysis lab, if someone could do at least some of these it would be very helpful.

2007-10-07 14:09:23 · 1 answers · asked by daniel T 3

if Heat is transferred from the system to teh surrounding then

A. Q (of system) is postive
B. Q (of system) is negitive
C. the system is doing work
D. the surrounding are doing work

2007-10-07 14:00:18 · 2 answers · asked by Anonymous

explain static and dynamic balancing

and

explain conservation of mass. refer to vinegar and baking soda experiment.



thankss!! :)

2007-10-07 13:48:30 · 1 answers · asked by nelliekellibelly 2

When 0.50 moles of lithium is reacted with excess nitrogen, 0.15 moles of lithium nitride are formed. What is the percent yield of the reaction? I got 90%, but teacher said 30%. Please verify

2007-10-07 13:44:34 · 1 answers · asked by Chuck 1

what are the elements that make up lipids?

what are lipids building blocks?

what are lipids unique features?

what are lipids functions?

any help is appretiated

2007-10-07 13:42:16 · 5 answers · asked by Anonymous

When hydrochloric acid reacts with magnesium metal, hydrogen gas and aqueous magnesium chloride are produced. What volume of 4.0 M HCl is required to react completely with 3.00 g of magnesium

2007-10-07 13:26:12 · 2 answers · asked by Anonymous