?

Im not sure how to do this.. please explain!! Thankyou so much!!

Please helppp!!

What element forms an ion with the electron configuration of [Kr] and a -2 charge?? (Please explain)

Please explain.

1) The mole fraction of nitrogen in air is 0.7808. Calculate the partial pressure of N2 in air

when the atmospheric pressure is 760 torr. Express your answer in atm.

If a sample of N2 at 1 atm of pressure is found to have 2.19% impurities of other gases,

what is the mole fraction of nitrogen in the sample

According to the equation:

MnO2(s) + 4HCl(aq) --> MnCl2(aq) + 2H2O (l) + Cl2(g)

How much MnO2(s) should be in excess to HCl (aq) to obtain 0.375 L of Cl2(g) at 298.15 degrees K, and 0.978 atm?

( I already converted the ml->L, C->K, and Torr->atm that was in the problem originally, I just dont know what to do next)

Calculate the mass of solid sodium chlorite that must be added to 1.50 L of a 0.100 M AgNO3 solution to precipitate all of the Ag+ ions in the form of AgCl (s)??

I dont understand .. please show me a step by step process. Thankyouou

SOMEONE GOOD AT CHEM PLEASE EXPLAINN

What are the Oxidation States of each.. and which element is being oxidized and which one is reduced?? Im really confused on how to do this please explain!!

1) In lab, you are given a 5.00 gram sample of Mgx(SO4)y ● aH2O.

a. You heat the sample in order to drive off the water in the sample. After cooling the crucible, the new mass of the sample is 2.44 grams. What is the mass of water in the sample?

b. You then dissolve the solid in water and isolate solid Magnesium. After filtering and drying the magnesium on a pre-weighed watch-glass you have the following data. Determine the mass of Mg in the sample: - show your work

Mass empty watch-glass 15.78 grams Mass watch-glass + Mg 16.27 grams

c. Determine the mass of sulfate by difference – show your work

d. Determine the empirical formula

redox, precipitation, acid/base or none of them?

1) Ba(ClO3)2(s) --> BaCl2(s) + 3O2 (g)

2) CaO(s) + CO2(g)--> CaCO3(s)

3) 2NaCl(aq) + K2S (aq) --> Na2S (aq) +2KCl (aq)

3.00x10^20 HF molecules?

18.0 picomoles of HF?

PLEASE ROUND TO SIG FIGS

3.00x10^20 HF molecules?

18.0 picomoles of HF?

A lot of things in my life aren't going right , this last week has just been horrible ..

Idk

Lets say we have element Se.

The mass number is 76

The number of neutrons is 42

The number of protons is 34

and the charge is -2

WHAT IS THE NUMBER OF ELECTRONS then since the charge is not neutral ??

Please explain how to figure out!!

In a combustion of Hydrogen gas , hydrogen reacts with water from the air to form water vapor . If you burn 53.4 grams of hydrogen and produce 477 g. of water, how much oxygen reacted?

PLEASE EXPLAIN !!

You have a sample of titanium metal. You mass it on a electronic balance and it has a mass of 7.52 grams. You decide to measure the volume of the sample by volume displacement. you fill a graduated cylinder with 35.2 mL of water. After dropping the titanium into the graduated cylinder, the volume now reads 36.9 mL. Determine the density of the titanium .

PLEAS ExpLAIN!!

PLEASE EXPLAINNNNNN