Question

covalent compound CCl4?

Answer 1

Carbon tetrachloride?

Answer 2

yup

Answer 3

compound N2O5?

Answer 4

DInitride pentoxide??

Answer 5

good

Answer 6

incorrect? :S

Answer 7

oh sorry, when you have two nonmetals, for the first element gets its full name spelled out, not the -ide suffix

dinitrogen, not dinitride :S

Answer 8

and the second?

Answer 9

keeps the -ide suffix, so pentoxide

Answer 10

What is the name for the compound N2O4?

Answer 11

Dinitrogen tetraoxide??

Answer 12

almost, tetra + oxide ---> tetroxide (it drops the a)

Answer 13

formula P2S5.

Answer 14

Pentaphosphorus disulfide

Answer 15

almost, just switch the prefixes (2 phosphorus atoms, 5 sulfur atoms)

Answer 16

but dont you have to switch

Answer 17

like would phosphorus have 5

Answer 18

hm? Pentaphosphorus disulfide would be P5S2 not P2S5

Answer 19

yeah but to make it neutral dont you swtich

Answer 20

you're thinking of charges, the compound is already neutral so don't worry about charges here

Answer 21

oh okay

Answer 22

A flask contains 0.500 mol of liquid bromine, Br2. Determine the number of bromine molecules present in the flask.

Answer 23

2.41 x 10^24

Answer 24

hm not quite

0.500 mol of Br2 molecules --> each molecule has 2 Br atoms, so ---> 1 mol of Br atoms --> avogadro's number of br atoms

Answer 25

79.91*6.022 x 10^23

Answer 26

79.91? no, it's just avogadro's number, the molar mass of the element is irrelevant here

Answer 27

6.022 x 10^23

Answer 28

ugh wait it asks for bromine molecules not bromine atoms >_> so just half of avogadro's number

i gotta read these more carefully

Answer 29

1.2044 x 10^24

Answer 30

(6.022 x 10^23)/2 = 3.011×10^23

Answer 31

wait whee are you getting two from

Answer 32

0.500 mol of Br2 molecules, or in other words, half a mole

half a mole = avogadro's number/2

Answer 33

the 2 signifies the half?

Answer 34

yes. dividing something by 2 is equivalent to taking half.

Answer 35

The fuel used in many disposable lighters is liquid butane, C4H10. How many carbon atoms are in 2.00 g of butane?

Answer 36

Last one

Answer 37

then im gonna go to sleep;.getting tired

Answer 38

first step: g of butane to moles butane --> divide 2.00/molar mass of butane

second step: moles of butane to moles of carbon. 1 molecule of C4H10 has 4 carbon atoms according to its formula so multiply step 1 result by 4

third step: moles of carbon to atoms of carbon, so multiply the previous result by 6.022e23

Answer 39

to save some time: molar mass of butane = 58.12

so

(2.00/58.12) * 4 * 6.022e23

Answer 40

8.29 x 10^22

Answer 41

good

Answer 42

Calculate the mass of 1.00×1024 (a septillion) molecules of water

Answer 43

This is the last one

Answer 44

10^24

Answer 45

but it would just be 1.00 x 10^ 24 times molar mass?

Answer 46

you need to convert the quantity to moles first

Answer 47

avagadros?

Answer 48

atoms ---> moles

divide by avogadro's

Answer 49

ye divide by avocado's

Answer 50

1.66

Answer 51

1.66 what?

Answer 52

um moles

Answer 53

yup. so now multiply by molar mass to get grams

Answer 54

wiat times 1.00 x 10^24?

Answer 55

nah, you just calculated 1.66 moles so multiply that by the molar mass to get g

Answer 56

molar mass so ?

Answer 57

the same number given?

Answer 58

the compound given in the question is water, so you need to multiply 1.66 moles * the molar mass of water.

Answer 59

29.9

Answer 60

yeah that's what i got too

Answer 61

is sig figs right

Answer 62

yeah they gave you 3 sig figs so the result also has 3 sig figs