Chemistry

Chemistry help please! [urgent]

Ive got this question and I really dont understand how to figure it out.. :( If one mole of pennies was divided so as to give an equal share to every person in Canada, how much would each person rece

Indicate the concentration of each present in the solution formed by mixing

Im very confused apon the process of doing these problems, i will offer more points to anyone who can answer them for me 1)42.0 mL of 0.130 M NaOH and 37.6 mL of 0.420 M NaOH 2)44.0 mL of 0.100 M and

Limiting Reactant help

I have this homework problem and I was hoping that someone could do it so i would be able to check my answer, thanks 10 grams of P2O5 react with 10 grams of 3H2O P2O5 + 3H2O -> 2H3PO4 1. Identify th

Activity effects for acid solution

What is the pH of a 0.03 M HCl accounting for activity effects? (H+ radius = 900 pm) What is the % difference if we assumed no activity?-To calculate the pH of the solution accounting for activity, w

A sample contains 20.823 grams of lithium metal. There are how many moles of lithium present

How do I go about solving this? Thanks!-use molar mass (20.823 grams of Li) ( 1 mole Li / 6.941 grams) = 3.000 moles of Li

Balancing half-reactions basic soln.

i know the steps and do not have problem doing these types on say br2+so2 -> br- + SO4^2- but im a little confused atone i ran across O2(g)=>OH^-(aq)-Rules for balancing Redoxequations: O = -2, unless

What do valance electrons determine about elements.

Help science homework!!!!!!!!!!-they determine how reactive the element will be. the closer to 8 it has, the more reactive it will be. so the halogens in group 17 are the most reactive elemtns on the

Given the following balanced equation, calculate the volume

Given the following balanced equation, calculate the volume of 0.278 M NaI that would be needed to react with all of the Hg2+ ion from 10.51 mL of a 0.168 M Hg(NO3)2 solution. 2NaI(aq) + Hg(NO3)2(aq)

What is the difference between the sum of the individual masses of the protons, neutrons, and electrons...

in an atom and the mass of the atom called?-mass defect the idea is the mass of the atom is never the mass of the sum of its parts.Because there is also energy that is observed as mass gained or lost

Calculating oxidation number of V in VOCl3

ok so oxidation number of oxygen is 2- and oxidation number of Cl is -1 which leaves X +-2 + -1(3)=0 which leaves 5 for v? what am i doing wrong-actually i think thats right. when youre calculating ox

How would you make this chemistry solution

How would you calculate to make the following solution: 10 ml of 100 mg/ml ampicillin (MW = 371.4 g/mole)-100mg/ml x 10ml = 1000mg or 1g ampicillin take 1g amp in 10ml water and stir.

What is the mass of 14.1 mol of the element nickel (Ni)

Also, How many molecules are contained in 0.900 mol O2? How many molecules are in 7.00 mol He? What is the mass of 0.0401 mol of the element sodium (Na)? How many molecules are in 0.0690 mol NH3?

Aluminium reacting with H2 (g) at STP - please help

2 Al (s) + 6 HCl (aq) ----------> 2 AlCl3 (aq) + 3 H2 (g) What is the mass of Al (s) needed to produce 508.8 mL of H2 gas at STP?? Any help with this question would be really appreciated!!!-2 Al + 6

ORGANIC LAYER WASHED WITH NAOH

What is the point in washing the organic layer with NaOH?-Washing an organic layer with a strong base separates a Brønsted acid into the aqueous layer.This is used for separating when there are multip

How to solve a simple HALF-LIFE question

The isotope of a certain element has a half life of 22 years. What percentage of a pure element sample prepare in may 2002, would have decayed by May 2009? The answer it gives is 42%, but Im not sure