Chemistry

How to calculate enthalpy change? I just don't get it, please help :(

I have a major chemistry exam in 3 weeks and im starting to freak out :\ Practice question: What is the enthalpy change for the following reaction? SiCl4(l) + 2H2(g) --> Si(s) + 4HCl(g) Compound......

Graphite - intermolecular bonding.

What going on with the molecule? Are the van der waals forces the attraction between the delocalised electrons and carbons positive nuclei only?-Graphite consists of a series of plates of six membered

Are there plants which are basic when they decompose

Yes. Plants decompose by nitrogen fixing bacteria that produce NH3.When added with water this becomes ammonia hydroxide, which is a base.

Why is mercury (II) sulfide less of an environmental concern than mercury (II) nitrate

Science help for chemistry please-mercury (II) sulfide has very little solubility and would release very little mercury (II) ion into the environment, while mercury (II) nitrate is quite soluble and w

Chemistry, finding PH, pOH and H+

A dilute solution of Ca(OH)2 has a concentration of 5.2x10^-4M Calculate PH POH and H+ and another problem I dont understand is What is the [OH-] of a solution with a PH of 3.95? im failing chemistr

Chemistry --> NaOBr or NaBrO

Which one is it and does it matter? If so why? Thankyou!-The reason is the bonds. The molecule is Na+BrO- so thje sodium is attached to the oxygen not the bromine.Hence it is writtren NaOBr to show

What does a jump in the curve mean

What does a large jump in the curve of a titration of a weak monoprotic acid with sodium hydroxide indicate?-During the beginning of titration, you reach a point where the pH doesnt seem to change.Thi

Open vessel at 27 c is heated until 3/5 of air in it has been expelled.find the temperature at which it heated

Find the air escaped out if vessel was heated to 900k find the temperature at which half the air escapes out.-Hello use V1/T1 = V2/T2 1) V1 = 2/5*V2 T1/V1 = T2/V2 300/(2/5*V2) = T2/V2 T2 = 5*300/2

How do I find the pH of this

Determine the pH of solutions with each of the following [H3O+] a. 2.0 x 10^-5 M Not asking for just the answer but how to do it-pH = -log([H3O+]) pH = -log(2.0x10^-5) pH = 4.70-Take the negative log

Chemisty molar mass and density HELP PLEASE!!

What is the molar mass of a gas with density 0.7 g/L at 770 torr and 40 degrees C? Thanks so much!-D = 0.7 (g/L) R = 0.0821 (L.atm/mol.K) T = degree C + 273.15....=> T = 40 + 273.15 = 313.15K P (1 atm

How to calculate molarity for this problem

1.6 L solution containing 1.55 g of dissolved KBr. The molar mass is 119.0 g/mole? Im confused about this problem-Molarity=mol of solute/L of solution or sumthin like that . But you convert g to mol f

In the following equation, identify the acid and base on the reactants side as well as their conjugates on the

In the following equation, identify the acid and base on the reactants side as well as their conjugates on the products side. H2O + H2O ↔ H3O+ + OH- PLEASE HELP ITS FOR HOMEWORK!!!-An acid-base conju

What is this symbol? I've been seeing it on a lot of questions

K-1 (K to the power of -1) ? Ive seen it on Heat capacity questions, like this - J mol-1 K-1 (I know J mol-1 = joules per mole) Ive looked everywhere and i just dont know what it is! Im sure this is

CHEMISTRY CALCULATION help

here are my following questions 1)2Ca+O2 (oxygen)==>2 Cao work out the mass of product made with 60 grams of calcium could you include the ratio too and explain? thanks :)-Yes here the ratio is sig

A question on stoichiometry, 10 points best answer.

A student is trying to determine the mass of aluminum oxide that is produced when aluminum reacts with excess oxygen. 4 Al + 3 O2 --> 2 Al2O3 The student states that 4g of aluminum reacts with 3g of o