Basic Chemistry Question

Basic Chemistry question?

Carryout the following operations, and express the answers with the appropriate number of significant figures.
a) 11,254.1+0.1983=
b) 320.55-(6104.5/2.3)=
c) 863*[1255-(3.45*108)]=
d) (0.0045*20,000.0)+(2813*12)=

Basic Chemistry Questions?

1) there is an electrostatic force between a metal and a non-metal ( Ionic bond). the potassium ion will have a +1 charge and oxygen will have a -2 charge. so K2O is the correct formula. (D)

2)You will need a balanced equation for the combustion of glucose:
C6H12O6 + 6 O2 -----> 6CO2 + 6H20

using the molecular weight of glucose, you can determine the # of moles of glucose
0.1127g X 1 mole glucose / 180.15588g = 0.000626 moles of glucose

now, according to the balanced equation, for every mole of glucose, you will produce 6 moles of CO2. So since you have 0.000626 moles of glucose:

Moles of CO2 = 0.000626 X 6 = 0.003753 moles

Using the molecular weight of CO2, you will be able to determine its mass
0.003753 mol X 44.0095 g/mol = 0.165 grams of CO2

3) First you need to know the total number of magnesium bromide ( MgBr2) moles there are in the solution.
5.00 g X 1 Mole/184.113g = 0.027157 moles of MgBr2

we now that there are 2 moles of Br ions for every mole of MgBr2 from the molecular formula. therefore,

# of moles of Br = 0.027157 X 2 = 0.054314

you get 1 mole of Mg ions for every mole of MgBr2, so

Moles of MgBr2 = Moles of Mg ions
Total # of ions = 0.02715 + 0.054314 =0.0815 moles of ions

4)The formula for percent yield is :
Percent yield = actual yield/ theoretical yield X 100%
so algebraically, solve for the actual yield and you should get approximately, 6.01 grams

Very basic chemistry question/help?

In all three cases, keep in mind that silver has only the 1+ oxidation state, so there's no need to use the roman numeral.

1) Ag2O is silver oxide.

2) Just AgNO3. You'd only use the roman numeral if you were writing out the name of the molecule. For example:
FeCl3 is Iron (III) Chloride.

3) AgClO4. See the above for explanation

I have a few Basic Chemistry questions?

Im trying to study for my test next week, but i dont seem to understand this material from my study guide. Can you help me elaborate on this info? If possible please explain the answer. I really need to know this stuff in order to pass my test

1.)The bond between F and Cl would be:
a.)pure covalent
b.)polar covalent
c.)ionic
d.)metallic

2.)Polar molecules have an equal number of positive and negative particles.
a.)True
b.)False

3.)Ionization energy and electronegativity are related to the periodic table in that:
a.)Both increase going across a row and up a column.
b.)Both decrease going across a row and increase going down a column.
c.)Electronegativity increases going across a row and up a column while ionization energy decreases.
d.)There is no relation.

4.)Select all that apply.

A nonmetal:
a.)is more likely to attract an electron than a metal
b.)is more likely to lose an electron than a metal
c.)requires more energy to lose an electron than a metal
d.)requires less energy to lose an electron than a metal

5.)When atoms from Group IA combine with atoms from Group VII:
a.)A nearly 100% covalent bond forms.
b.)The bond will be ionic.
c.)A weak bond will form.
d.)The resulting compound will be very unstable.
e.)A great deal of energy is absorbed.

I Promise to give 10pts

Basic Chemistry Question - 10 Points?

1 mole is 6.022x10^23 individual units.

So
1 mole of a molecule is 6.022x10^23 molecules
1 mole of an element is 6.022x10^23 atoms of that element

2 moles of O2 molecules will contain
2 x 6.022x10^23 molecules of O2
= 1.2x10^24 molecules of O2

BUT each 1 molecule of O2 has 2 Atoms of O

Therefore there are 2 x as many atoms as molecules

Number atoms = 2 x number molecules
= 2 x 1.2x10^24

= 2.4x10^24 Atoms (2 sig figs)

Acid/Base Chemistry Question?

Here's the question:

Ephedrine, a central nervous system stimulant, is used in nasal sprays as a decongestant. This compound is a weak organic base:

C10H15ON(aq) + H2O(l) ===>C10H15ONH+(aq) + OH-(aq)

A 0.035 M solution of ephedrine has a pH of 11.33. Calculate Kb for ephedrine.


I'm stuck, can someone help!!!

Basic Chemistry Questions - What are atoms, etc.?

This is NOT homework, just some questions that I would like to know the answer to. I am not asking anyone to answer all the questions, even one would be fine!


What is the difference/relation between an atom, a molecule, a compound, a particle and an element?

What conducts electricity better, liquid or aqueous?

What is a mole?

What is the relation between moles, atoms, number of particles and mass and molar mass?

What is the difference between the molecular mass, and the molar mass, atomic mass and the relative atomic mass?

How many orbitals are there in each subshell? S, P, D and F.

What is the difference between polar and non-polar?
What is dipole-dipole?



Thanks!
Any help is appreciated