Chemistry - October 2006

1) 5.34g of a salt of formula M2SO4 (Where M is a metal) were dissolved in water. The sulphate ion was precipitated by adding excess barium chloride solution when 4.66g of barium sulphate (BaSO4) were obtained .

(a)How many moles of sulphate ion were precipitaed as barium sulphate?

(b)How many moles of M2SO4 were in the solution?

(c)What is the formula mass of M2SO4?

(d)What is the relative atomic mass of M?

(e)Use a table of relative atomic masses to identify M.

(2)(a)Explain what is meant by "hydrogen peroxide has the molecular formula H2O2'

(b)2H2O2------>2H2O2 + O2
What mass of oxygen can be formed from 17g of H2O?

(c)What mass of oxygen can be formed from 17g of H2O2 if 1 g of maganese dioxide catalyst is used?

(3)What mass of solid is precipitated when excess dilute sulphuric acid is added to 100cm^3 of 2 M barium chloride solution?

Explain plz.

2006-10-04 11:42:18 · 6 answers · asked by candyisland2002 2

Chromium (atomic mass= 51.9961 amu) had 4 isotopes. their masses are 49.94605 AMU, 51.94501 amu, 52.94065 amu, and 53.93888 amu. the first two isotopes have a total abundance of 87.87% and the last isotope has an abundance of 2.365% what is the abundance of the third isotope? Estimate the abundances of the first two isotopes. - whats the answer and how do u get it.

2006-10-04 11:42:15 · 1 answers · asked by xoMadisonxo 2

2006-10-04 11:18:32 · 4 answers · asked by steviedb9 1

(a) 2 MnO4-(aq) + 10 Cl-(aq) + 16H +(aq) 5 Cl2(g) + 2 Mn2+(aq) + 8 H2O(l)

Oxidizing agent:
Reducing agent:

(b) 8 H+(aq) + Cr2O72-(aq) + 3SO32-(aq) 2 Cr3+(aq) + 3 SO42-(aq) + 4 H2O(l)

Oxidizing agent:
Reducing agent:


6HCl(aq) + 2HNO3(aq) + 3Cu(s) 2NO(g) + 3CuCl2(aq) + 4H2O(l)

Oxidizing agent:
Reducing agent:

2006-10-04 11:16:25 · 2 answers · asked by Amy 1

We did a calorimetry experiment in class in which we burned nuts (Brazil nuts and cashews) to find out how much energy they contained. What do the nuts contain that makes them easily burn? Also, the nuts didn't burn entirely. Why didn't they, and what is the substance that remained?

2006-10-04 11:03:13 · 5 answers · asked by Cosette 3

What is the base in this equation?
(CH3)3N(aq) + HCl(aq) (CH3)3NH+ (aq) + Cl -(aq)
Acid: HCl

what is the acid in this equation?
NH3(aq) + HCN(aq) NH3+(aq) + CN -(aq)
Base:NH3

2006-10-04 10:55:35 · 3 answers · asked by Amy 1

a 1.0000 g sample of water weighed in air at 24°C should occupy what volume in ml

2006-10-04 10:49:40 · 4 answers · asked by asknow 1

Aluminum sulfate, known as cake alum, has a remarkably wide range of uses, from dyeing leather and cloth to purifying sewage. In aqueous solution, it reacts with base to form a white precipitate.


Total equation:
1 Al2(SO4)3 (aq) +6 NaOH (aq) ----> blank (aq) + blank (s)

net ionic:
blank (aq) + blank (aq) ---> blank (s)



B) What mass (g) of precipitate forms when 137.5 mL of 0.636 M NaOH is added to 517 mL of a solution that contains 18.0 g aluminum sulfate per liter?



If anyone has any ideas please help with what you can. Thank you sooo much.

2006-10-04 10:40:40 · 2 answers · asked by Amy 1

i need answers asap.....pls.....

2006-10-04 10:30:52 · 8 answers · asked by Rune 1

Reaction is P4+6I2---> 4PI3

It says what mass of P4 is needed to produce 52.6 g of PI3if the reaction has an 86% yield?

what does the % yield mean for this? is the 52.6 g 86 % and i have to solve this using the 100% yield, or is the 52.6 g 100% yield and i have to solve this problem using 86% of it?
im confused.
someone plz help!

2006-10-04 10:24:06 · 4 answers · asked by Anonymous

2006-10-04 10:22:18 · 3 answers · asked by Dude J 1

2006-10-04 10:19:11 · 2 answers · asked by Amy 1

One question is "What happens when phenolphthalein solution is mixed with hcl solution". I don't just want the answer to this, but can anyone tell me how I'd go about finding out the answer please?

2006-10-04 10:18:52 · 2 answers · asked by Anonymous

2006-10-04 10:17:33 · 7 answers · asked by Amy 1

What is the mass of the precipitate formed when 12.0 mL of 0.150 M NaCl is added to 25.00 mL of a 0.0500 M AgNO3 solution?

2006-10-04 09:45:35 · 4 answers · asked by jasmine m 1

2006-10-04 09:43:35 · 1 answers · asked by TPatel 1

2006-10-04 09:41:29 · 1 answers · asked by TPatel 1

2006-10-04 09:34:33 · 1 answers · asked by ejade00 2

I need to write a balanced equation for the reaction of Zinc(metal) and Hydrochloric acid (aqueous).
I know it's simple enough cos I used to do it but my brain is rejecting all sense!
Anyone able to answer to a simpleton?
Cheers:D

2006-10-04 09:32:06 · 5 answers · asked by Anonymous

Isotope 1;
relative isotopic mass- 63.0
% abundance- 77.2

Isotope 2;
rel. isotopic mass- 65.0
% abundance- 22.8

when i calculate the relative atomic mass of the element i got 4878.42 i think it's wrong..


anyone help me pls..

2006-10-04 09:21:32 · 1 answers · asked by KC 1

in a limiting reactant problem? do i treat it like a regular arrow? or does it have any effect on the answer?

2006-10-04 09:19:44 · 6 answers · asked by Anonymous

2006-10-04 09:17:23 · 7 answers · asked by mapleafgal sweet an delicious 1

what do i need to do this?
and how should i go about doing this?
is there any way to speed up the process?

2006-10-04 09:01:22 · 4 answers · asked by psycho 3

2006-10-04 08:56:35 · 17 answers · asked by Anonymous

What i mean by this question is black and whites are shades of colours, but for an example, the colour blue, how does it turn blue, are there chemicals or something that react to make the colour.

Like peoples eye colour, the information is in our genes, but how does the colour get there, are their hormones that make the colour etc?

2006-10-04 08:51:05 · 8 answers · asked by Anonymous

The question is here:
http://ca.blog.360.yahoo.com/blog-LDLB08k9fqL4u3yfbggy

How can you combined the four molecules on the left to make the one on the right?

2006-10-04 08:41:04 · 1 answers · asked by Hard Rocker 3

2006-10-04 08:39:28 · 10 answers · asked by highcap10 2

2006-10-04 08:34:10 · 4 answers · asked by stupid dude 1

2006-10-04 07:59:36 · 1 answers · asked by Kashmira A 1

can u tell me how many moles of Ti and Cl atoms were reacted?

2006-10-04 07:30:08 · 3 answers · asked by KC 1