Question

Help with two quick questions please!

Answer 1

For 12, is it higher?
KCl -> only 1 electron of each K atom is involved in the bonding
CaO -> 2 electrons of each Ca atom are involved in the bonding => stronger interaction.
I think..

For 20,
\[nm = 10^{-9}\]\[23nm = (2.3 \times 10) \times 10^-9 = 2.3 \times 10^{-9+1} = ...?\]

Answer 2

Yes @Callisto is right - Ca and O each are doubly charged, whereas K and Cl are singly so. Hence, due to a larger magnitude of charge, CaO molecules will have a larger inter-molecular attraction between the molecules, and hence more energy will be required to separate CaO molecules into a liquid phase. Thus, CaO --> higher melting point.

Answer 3

**into *its liquid phase

Answer 4

ok got it and for 20 it's B then? 2.3 x 10^-8?

Answer 5

Yo, it's B.

Answer 6

k but I don't quite get q20 still

Answer 7

1 nano meter = 10^(-9) meters --> are you familiar with this?

Answer 8

nm = nanometer = 10^-9 m
Since n = 10^-9

Answer 9

nm = nanometer = 10^-9 m <<the m is metres right? not anything else? I want to make sure

Answer 10

yep kk

Answer 11

nm=nanometer
n = nano = 10^-9
m = meter
nanometer = 10^-9 meter = 10^-9 m

Answer 12

yep kk and why the do u +1 on the negative nine power?

Answer 13

isn't it fine just to tell it as power -9?

Answer 14

that's wat i sort of don't get.

Answer 15

2.3 x 10 x10^-9 = 2.3 x 10^(-9+1) ...
It's law of indices
\[x^m \times x^n = x^{m+n}\]

Answer 16

now, x=10 , m=1 , n=9

Answer 17

yep k i get it but why is it plus one may I ask?

Answer 18

10 = 10^1

Answer 19

so we converted nm>m already

Answer 20

and why do we have to times 10^1 again?

Answer 21

23 = 2.3 x 10 = 2.3 x (10^1)

Answer 22

1 nano = 1 billionth of any thing.

applies for grams, meters, liters or simply any form of measurement!

Answer 23

k I sort of get it, but I'm still a bit stupidly confused as I'm never good with big measurement conversions like this one, but thanks for helping me guys.

Answer 24

Hmm... what are you confused with?

Answer 25

23 = 2.3 x 10 = 2.3 x (10^1) = 2.3 x 10 x10^-9 = 2.3 x 10^(-9+1)
hmm why you have to split it I guess? I'm not too sure myself but yeh

Answer 26

like I'm okay with normal measurements convert--- 100cm to m then you just divide by 100 obviously and u get 1m

Answer 27

because you can simplify 23x10^-9 ....
and the option you've got are all start with '2.3' not '23'

Answer 28

ah kk

Answer 29

there's probably only be one question like this on the exam or maybe none at all but I think I got the idea now, although I may forget.

Answer 30

Take 12mm as an example,
you know 1mm = 0.001 m = 1x10^-3 m
12 mm = 12 x 1mm = 12 x (0.001m) = 12 x 12^-3 m
= (1.2 x10) x 10^(-3) m = 1.2 x 10^(-3+1) m = 1.2 x 10^-2 m

Answer 31

Oh... seems I'm making it more complicated :|

Answer 32

Great patience! @Callisto :)

Answer 33

not as patient as you @apoorvk :P

Answer 34

lol don't worry, I got most of it, it's probably only going to be a multiple choice one and if it's like this question again I will just remember x 10^-9 +1 to the power.

Answer 35

and I know I'm stupid but yeh, it just doesn't get into my head for some reason like I do get it but not fully for some reason.

Answer 36

Lol, me? and patient? Haha lol!! am more like 'a patient' :P

Answer 37

If it is 234nm,
then it's (2.34x10^2) x 10^-9 m = 2.34 x 10^(-9+2)m = 2.34 x 10^-7 m

Answer 38

k, I got it and I remember it this way, how many decimal places so two in the above example so +2 to the power.

Answer 39

@JayDS you have probably entangled yourself in this problem too far right now - got take a break and come back to this with a clear mind, you 'll get this in a jiffy!! ;)

Answer 40

Problem after refreshment:
200nm = _____ m ?

Answer 41

200nm = 2 x 10^2 x 10^-9m = 2 x 10^-7m

Answer 42

right?

Answer 43

Yup!~ next:
0.02 nm = ___m ?

Answer 44

0.02 nm = 2 x 10^-2 x 10^-9 m = 2 x 10^-11 m?

Answer 45

Yeah!!~~~ You'll get a pass, at least!!~~~

Answer 46

haha thx! kk I got to study for my other subject now then-Accounting!! BOO FOR LAST MINUTE STUDYING!!! Greatly appreciated for all the help Callisto & apoovrk for being the assistant may I say. Cya!