Entrance Ticket 11/17/14

Starting CH 10. Chemical Quantities & the mole.

1.) What is a mole (in chemistry)?

2.) A mole is also called __________’s number.

3.) If you were to stack 1 mole of poker chips, how high do you think it would go?

Answers

1.) What is a mole?

A mole is the number 6.022 x 1023

2.) A mole is also called

Avogadro’s number.

Amedeo Avogadro

How big is a mole? (You need a calculator today)

•Take a ruler and measure the height of ten poker chips in centimeters. Be as precise as you possibly can.

•How would you find the height of a single poker chip? Do it.

•Write down the height of a single poker chip for your group

•How high would a mole of poker chips be?

•How high would a mole of poker chips be in kilometers? (convert from cm to km)

How big is a mole?

•Do you have any idea how high your stack of poker chips would go? Well, let’s find out.

•The distance from Earth to the Sun is about 150 million km. (1.5 x 108 km)

•How many times would your stack of poker chips go to the sun and back?

How big is a mole?Yes, that’s correct. A mole of poker chips would stack to the sun and

back about 4 billion times!

Conclusion:

The mole is a REALLY BIG NUMBER!

WHY?

How big is a mole?Chemists and scientists use this # to measure amounts of matter, and matter is made of particles that are incredibly small!

So small that if you had 1 mole of carbon atoms, it would only weigh 12 grams (0.026 lbs)!

Entrance Ticket 11/18/14

1.) What did you learn about Avogadro’s # in class yesterday? Why do we use it in chemistry?

2.) Look at the periodic table. The average atomic mass is also the molar mass. What does molar mass mean?

3.) What is the molar mass of carbon monoxide (CO)?

Answers2.) Molar mass means how much an

element or compound weighs in grams per mole (g/mol).

3.) Carbon weighs 12 g/mol Oxygen weighs 16 g/mol

So the molar mass of CO would = 12 + 16 = 28 g/mol

Entrance Ticket 11/19/14 Yesterday, we learned how to find molar

mass, a vital skill to your success in this class. What does molar mass tell you?

Find the molar mass of….

1) NH4NO3 3) H2SO4

2) NaOH 4) Al2(SO4)3

Answers

1) 80.06 g/mol 3) 98.09 g/mol

2) 40 g/mol 4) 342.17 g/mol

Check your answers for mass (g) to moles (mol) conversions

11.) 0.5 mol 15.) 0.01 mol

12.) 0.2 mol 16.) 19.7 mol

13.) 1.97 mol 17.) 0.000046 mol or

4.6 x 10-5 mol

14.) 2mol 18.) 1.24 mol

Entrance Ticket 11/20/14*Please get out your labs

1.) If you weigh 14 grams of carbon monoxide (CO), how many moles is this?

2.) How many carbon monoxide molecules is this?

3.) How many total atoms is this?

Answers1.) 14g CO x (1mol/28g)= 0.5 mol CO

2.) 0.5molCO x (6.02x1023molecules/1mol)=

3.0x1023 molecules CO

3.) 3.0x1023 molec CO x (2 atoms/1molec)=6.0 x 1023 atoms

Lab Experiment

Please get out your % Composition of Hydrates Lab It is on pages

20-22.

Make sure all of your 1 step and 2 step conversions are completed by tomorrow!

Entrance Ticket 12/1/141.) How many grams would 3 moles of sodium

bicarbonate, NaHCO3, weigh?

2.) What is the mass of 2.5 moles of water?

3.) How many water molecules are in 2.5 mol of water?

Answers

1.) 3 mol NaHCO3 x (84g/1 mol) =

252 g NaHCO3

2.) 2.5 mol H2O x (18g/1 mol) = 45 g H2O

3.) 2.5 mol H2O x (6.02x1023 molecules/1 mol)=

1.5 x 1024 H2O molecules

10.1 & 10.2 study guide

10.1 use these: 10.2 use these:

-atomic mass -Density

-mole -mole

-Avogadro’s # -molar volume

-6.02x1023 -22.4

-molar mass -22.4L/1mol

Homework Help

16) you’re all good!17) iron (II) hydroxide is Fe(OH)2

18) you’re all good!19) dinitrogen trioxide is N2O3

20-21) 1 mole of any gas at STP = 22.4 L

STP: Standard Temperature & Pressure

0°C 1 atm

Entrance Ticket 12/3/141) How many moles is 1.34 grams of

Copper Sulfate (CuSO4)?

2) How many moles is 0.46 grams of water?

3)Please have out: -labs-10.2 #16-21-10.1 & 10.2 packet

Answers1) 1.34 g CuSO4 x (1 mol/159.65 g) =

0.0084 mol

2) 0.46 g H2O x (1 mol/18 g) =

0.026 mol

Hydrates Lab Help #1) To find the mass of the pure copper sulfate,

you need to subtract the mass of the empty crucible from the final mass after heating.

#2) Take your answer from #1 and convert it to moles. (you should know how to do this)

Hydrates Lab Help #3) a) Find the mass of the water lost by

subtracting the mass after heating from

the mass before heating.

b) Convert that mass to moles.

#4) Divide your moles of water by moles of copper sulfate to find the ratio of water to copper sulfate!

Hydrates Lab Help

The actual “x” in the hydrated copper sulfate is….

5

Hydrates Lab Help

#5a.) Take your mass of water and divide it into the mass of the hydrated salt (mass before heating minus the crucible). Then multiply by 100 to make a %.

Hydrates Lab Help

#5b.) Use the formula CuSO4 • 5H2O to find the % mass of water.

5H2O

CuSO4 • 5H2O

Entrance Ticket 12/2/13

-Please get out your labs and your conversions practice page

1) How many formula units are in 500. grams of Copper Sulfate (CuSO4)?

2) If you have 2.41 x 1024 formula units of KOH, how much would it weigh?

Answers

500gCuSO4 x (1mol/159.6g)(6.02x1023f.u./1mol)

= 1.89 x 1024 f.u. CuSO4

2.41x1024f.u.KOH x (1mol/6.02x1023f.u.)(56.1g/1mol)

= 225 g KOH

Entrance Ticket 12/3/13

1) Find the molar mass of carbon disulfide (CS2).

2) What is the mass of 4.0 mol of CS2?

3) How many CS2 molecules is this?

4) If you weighed out 100.0 grams of CS2 in the lab, how many molecules are in your sample?

Answers

1) 12 + 32.1 + 32.1 = 76.2 g/mol

2) 4.0 mol x (76.2g/1mol) = 304.8 g

3) 4.0 mol x (6.022x1023 molecs/1mol) = 2.4x1024 CS2

molecules

4) 100g (1mol/76.2g)(6.022x1023molecs/1mol)= 7.9 x 1023 CS2

molecules

Practice1) What is the mass of 1.81 x 1024 silver nitrate

(AgNO3) formula units?

2) What does STP stand for and what are its values?

3) What is the volume of 6.21 moles of carbon dioxide gas at STP?

Answers1.) 1.81x1024 f.u.x(1mol/6.022x1023)(169.9g/1mol)

= 511 g AgNO3

2) STP stands for standard temperature and pressure. Standard temperature is 0°C and standard pressure is 1 atm.

3) 6.21 moles CO2 (22.4L/1 mol) = 139 L CO2

Practice1.) If you have 300 grams of Chlorine gas, Cl2,

then how many moles is this?

4.2 mol

2.) What is the volume, in liters, of Chlorine gas from problem #1 at STP?

94 L

3.) How many Chlorine molecules are there from problem #1? How many total atoms?

2.5 x 1024 molecules, 5.0 x 1024 atoms

Practice

1.) If the mass of a sample of water is 9.0 grams, how many water molecules are in the sample?

3.0 x 1023 water molecules

2.) If you were to heat the water from #1 into steam, what volume would it have at STP?

11.2 L

Answers

1.)

9.0g x (1 mol/18 g) (6.02x1023 molec./1 mol) =

3.0 x 1023 water molecules

2.) 0.5 mol x (22.4 L/ 1 mol) = 11.2 L H2O

Understanding the mole1) Which of the following has more total

molecules?

a) 1 mol of NH3 c) they have the same

b) 1mol of CO

2) Which of the following has more total atoms?

a) 1 mol of NH3 c) they have the same

b) 1mol of CO

Practice1) If you have 4.0 moles of carbon dioxide

(CO2), how many carbon dioxide molecules is this?

2) Look at your answer to #1. Now, figure out how many total oxygen atoms are present if you have 4.0 moles of CO2.

Answers#1)

4.0 mol CO2 x (6.02 x 1023 molec./ 1 mol)=

2.4 x 1024 CO2 molecules

#2.)

2.4x1024CO2molec. x (2 atoms O / 1 molec.CO2)=

4.8 x 1024 atoms O

Today…Are there any questions from the

Hydrates Lab or CH 10 practice problems?

Make sure that you can do 1 step and 2 step conversions using molar mass, Avogadro’s #, and volume of a gas @ STP.

More Practice1) How many grams would 5.2 moles of

C6H12O6 weigh?

2) 100. g of oxygen gas (O2 ) is equal to how many moles of O2 ?

*Chapter 10 quiz tomorrow

Answers

1) 5.2 mol C6H12O6 x (180g/1mol ) =

940 g C6H12O6

2) 100. g O2 x (1mol/32.g) = 3.1 mol O2

More Practice!1) In the lab you weigh a sample of liquid

nitrogen (N2) and find it has a mass of 328.4 grams. How many moles is this?

2) How many N2 molecules are present in question 1?

3) If all of the liquid nitrogen turned into nitrogen gas (N2), what would its volume be at STP?

More Practice!1) 328.4 g N2 x (1mol/28.0g) = 11.7 mol N2

2) 11.7 mol N2 x (6.02x1023molec./1mol) =

7.04 x 1024 molecules N2

3) 11.7 mol N2 x (22.4L/1mol) = 262 L N2

More Practice: Make your own!

1) With your group, write down on a small piece of scratch paper your own conversion problem.

Hint: Pick a substance...pick an amount of that substance (grams, moles, particles or liters)...then ask to change to different amount of (grams, moles, particles or liters)

Mole Joke

Q: What did Avogadro teach his students in math class?

A: Moletiplication

Welcome to…Mr. Melton’s Chemistry class!

What is chemistry???Chemistry studies matter and the changes that matter undergoes

What is matter?Matter is anything that has mass and volume.

Can you give some examples?

Chemistry…Is chemistry important?

Matter & Change

Matter usually changes in two different ways… chemically and physically.

What is the difference between chemical change and physical change?When matter changes physically it is still the same substance, it has just changed its physical form. In chemical change matter changesinto a new substance

An example of chemical changeCOMBUSTION!

Have you heard of combustion?

What do you think of when you hear combustion?

How about an example?

Methane bubbles!

Chemical ReactionsIn chemistry, we explain chemical change

by writing out chemical reactions.

Does anybody know what substance is necessary for combustion?

That’s right! Oxygen!