Course Notes

•Mole Concept

•Defining moles

o1 skin mole of elements has a mass equal to the molecular pounds in grams. oexamples

1 mole WATER is the range of molecules in 18. 015 g WATER

1 gopher H2 is definitely the number of elements in installment payments on your 016 g H2.

o1 mole of atoms contains a mass equal to the atomic weight in grams. o1 mole of particles sama dengan 6. 02214 x 1023 particles for any substance! Prove this by simply converting one particular mole to grams to daltons to particles for just about any substance. •vocabulary

omolar mass is the mass of one mole of a compound

bridge between moles and grams in unit change problems oAvogadro's number is the number of elements in one gopher for any element bridge among molecules and moles in unit conversion problems Using chemical formulations

•molecular formulas give atom-to-atom and mole-to-mole ratios oexample: molecular method C6H12O6

atom-to-atom ratiosatom-to-molecule ratiosmole-to-mole ratios (elements)mole-to-mole ratio (compound) 6 atoms C

doze atoms L

6 atoms C

six atoms O

12 atoms H

6 atoms O6 atoms C

1 molecule

12 atoms H

you molecule

6 atoms O

1 molecule6 mol C

12 mol H

6th mol C

6 mol O

doze mol L

6 mol O6 mol C

you mol C6H12O6

12 mol H

one particular mol C6H12O6

6 mol O

1 mol C6H12O6

•problems that ask you to bring up one compound to another require mole-to-mole proportions oexamples

How many grms of H2 can be obtained from the electrolysis of 10. 0 g of H2O? How many grms of CuO can be made out of a piece of water piping wire weighing 0. 2134 g? 2. 04 g of carbon reacts with 5. 44 g of O2 to form 7. 48 g of compound. How many atoms of To per atom of C are through this compound?

Chemical formulas and elemental structure

•mass percent: percent of total sample mass led by a particular component odetermine experimentally by decomposing test into components and weighing the distinct components determining water of hydration

combustion analysis of hydrocarbons

•finding element mass percents by a chemical formula

ostrategy: convert the mole small percentage of aspect in compound to a mass portion oprocedure

1 . Write a subscript X from your formula while (X mol element as well as 1 mol compound) installment payments on your Convert moles of element to grms (using the atomic weight) 3. Convert moles of compound to grams (using the gustar mass) four. Multiply by simply 100%

examples

To how many significant figures you have determine the proportion of carbon dioxide in a medication sample to tell apart cocaine (C17H21O4N) from aspirin (C9H8O4)? Vitamin B12 can be 4. 34% Co. When there is only one atom of Company per molecule of vitamin, what is the molar mass of cobalamin?

finding empirical formulas by element mass percents

0. Write the mass percent being a mass (mass percent is merely mass per 100 g sample). 1 ) Convert every single mass to moles.

2 . Divide every single molar sum by the tiniest molar quantity.

3. Across the mole proportions to the closest whole quantity or straightforward fraction. Employ significant figures to guide the selection of whole number or small fraction! 4. If possible, scale the ratios in order that all are complete numbers. These are generally the subscripts in the scientific formula. oexamples

elemental examination of a pure compound separated from tea leaves provided the following benefits: 49. 48% C, a few. 19% They would, 28. 85% N, 16. 48% U. What is the empirical formula of the substance?

g component per 75 g samplemoles element every 100 g samplemole ratiosimplified ratio 49. 48 g C4. 11952 mol C3. 999394

5. 19 g H5. 1490 mol H4. 99885

28. 85 g N2. 05973 mol N1. 999662

of sixteen. 48 g O1. 03004 mol O11

... The empirical formulation is C4H5N2O (it's caffeine).

What is a empirical mixture of a filtered drug sample that is 74. 27% C, 7. 79% H, doze. 99% In, and 5. 95% U? What is a empirical formula of an flat iron oxide that 70. 0% Fe and 30. 0% O? What is the molecular formula of a compound that is 5. 93% H and 94. 07% O, with molar mass 34. 015 g?

Employing Chemical Equations

opredicting sum of compound produced or consumed in a chemical reaction coefficients in well-balanced equation connect moles of one substance to...