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hi Im a chemistry flop, please help :rlytearpls:

The relative molecular mass, Mr, of copper(II) sulphate, CuSO4, is 160.
The relative molecular mass, Mr, of water is 18.
What is the percentage by mass of water in copper(II) sulphate crystals, CuSO4.5H2O?
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I need help  :cry:  Im in geometry, and we are starting with some basic algebra and all that good stuff, but I kinda forgot some steps and I have a quiz tomorrow. I went over my notes but i have no idea what i did so yeah..

 

both of them are fractions btw..so 3x over 5 equals 4 over 3 and we are solving for x.

 

3x/5 = 4/3

cross multiply the denominators,

3x*3 = 4* 5

simplify,

9x = 20

then divide both sides by 9

x = 20/9

 

hope that helps! If youre confused feel free to ask~

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One more question..how would you solve this? 

 

yccedgm.jpg

 

Since you have to solve for c, you can start by rearranging the equation to make 'c' alone on one side (the subject of the formula)

so divide both sides by mT (to leave c alone on the left side)

q/mT = c

then you can substitute the values for the variables

-302/(5.37 * -35) = c

then solve it with your calculator

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1968.34264?

It should be somewhere around -1.8

-302 /(5.37 x 35)

multiply the 5.37 by the 35 should give you around 175

then do -302/ 175 

it should equal something around -1.8

 

sorry for the late reply lol


Boo

omg youre a very scary fruit

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Hey everyone! I just started school lol and I'm rusty, can anyone tell me what significant digits are? And when solving a question how do I round the answer?
Also were going to have a debate soon, if anyone has any opinions on either sides of the death penalty argument please share,
Thanks in advance^^
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Significant digits are significant figures right? (sig fig for short)
 
If so, it's digits that are used to make measurements look more precise?
 
From what I remember here are the rules:
1. All non-zero numbers are significant. (i.e. 1,2,3,4,5,6)
2. Zeros are only significant when they are either:
a. in between non-zero numbers (i.e in the number 4005687 the zeros are significant)
b. when a decimal point is put after the final zero (i.e. 3240.)
c. when there are zeros after a decimal point (i.e. 19.001)
 
3. If a zero is in a number without following any of the above rules it is insignificant (i.e in the number 4600 the 2 zeros are insignificant)
4. if the number if there a zeroes before a decimal point (without any other non-zero numbers before it) like this (0.00000001) those zeros are also insignificant.
 
Using these rules you know how many sig figs are in a number...examples:
 
a) 2400 has 2 sig figs (Rule #3)
b) 2003 has 4 sig figs (Rule #2a)
c) 6. has 1 sig fig (Rule #1)
d) 6.00000000012 has 12 sig figs (Rule #2c)
e) 0.003 has 1 sig fig (Rule #4)
 
is this what you wanted explained?

YES THANK YOU SO MUCH :D
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Can you help me with these..


-29.5 = 9 + 4.5(d-8)


and


5 - 2.5(1.9.5x) = 18.5

First lets get the brackets by itself by subtracting nine from both sides
-29.5 - 9= 4.5(d-8)
-38.5=4.5(d-8)
Divide both sides by 4.5

-38.5/4.5 = d-8
-8.333 = d-8
Then add 8 to both sides
-0.333 = dd

I don't get the second question, there are three decimal points lol Edited by pimo
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For my English class I have to write an informational essay, and the topic is "How are Americans more privileged or not as privileged as citizens of other countries?" So if any of you guys has articles or websites about the topic, please give me the links.

Try checking out the water system in the US compared to in developing nations, or water consumption rates
Lol I can't research right now but some ideas u can search for are equality (gays, genders, even race),education and maybe things your government provides for you that isn't available in other places
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i would've said that 2400 has 4 significative figures but then where i live we'd never write "6." (we don't even use decimal points we use commas)
because if you measure or calculate something and say that the result is 2400 then it means that you're sure that there are two zeros after your 24, or at least that's what i've always learned
a rigorous way of writing it with 2 significant figures would be "2.4*10^3" i think?? i'm gonna need someone to correct me if i'm wrong
i'm curious now, where are you from?? because maybe the difference comes from country conventions

I'm from Canada, my physics teacher is the same way
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Can someone help me? I have no idea what I'm doing. Can someone show me the work and explain it to me?
1. A parking garage charges $1.50 for the first hour and $0.75 per hour for each additional hour or part of an hour. How many dollars will it cost Bill to park in the garage for 5 1/2 hours.

2. Given f(x) = x^2+2x+1/x^2-1 , find f(2)/f(0)

3. Vick's Video offers two different membership plans. One plan has a $25 annual membership fee and it cost $1.50 each to rent videos. The other plan has no membership fee but it cost $3 per video rental. What is the fewest numbers of videos Sam can rent in one year for which the first plan is the least expensive.

nvm I didn't get the question, I think Athena answered better Edited by pimo
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im not sure, we just started this chapter but im just working ahead so do my work for me pls n thanks, i love my fangoes 

do you know how to draw the vector diagram? draw and add the vectors, then using trig you can find the rest

 

 

anyone know how to draw tangent lines to a graph on excel? 

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I need more help. Please help me. Thank you!

[font='Helvetica Neue']1.At a convention, each guest was given a ticket. 40% of the guest received red tickets, 3/8 received blue tickets, 20 percent green tickets, and 20 guest received yellow tickets. How many guest attended the convention received blue tickets?[/font]
[font='Helvetica Neue']2.Three pencils and two erasers cost $0.60. Two pencils and three erasers cost $0.55. How much will it cost to buy 7 pencils and erasers?[/font]

[font='Helvetica Neue']3.[/font][font='Helvetica Neue'] A student's grade improved 20% over the grade for the marking period. If the student's current grade for the previous marking period? [/font]

[font='Helvetica Neue']4. Six students took a test. The arithmetic mean of their was 84. 5 of the scores were 68,92,90,86 and 72. What is the sixth score? [/font]

for number 4, multiply 84.5 by 6. Then subtract all the known scores from that number, you're left with the last kids score
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Sorry i missed one part 
3.[font='Helvetica Neue', Helvetica, Arial, sans-serif] A student's grade improved 20% over the grade for the marking period. If the student's current grade is 90, what was the grade for the previous marking period? [/size][/font]

Well his new grade is his old grade times 120%
Old grade x 1.2=90
Old grade =90/1.2
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jj0n7m.png

i must've missed something in the notes because i have no idea how to get the second part! 

soo the stone is unifromly accelerating (because of gravity)

state your givens then find the equation you need to use out of the 5 equations for uniform motion

2057736.png?535

 

t = 3.41

d = -57

a = -9.8 (gravity)

vf = ?

 (Im just gonna call Vfinal v in the calculations)

 

 

d= vt - (at^2)(0.5)

-57 = 3.41v - (-9.8)(3.41)^2 * (0.5)

-57 =3.41v + 56.98

-114/3.41 = v

v = -33.4

 

since its speed no need for the negative direction so it should be 33.4 m/s  yikes sorry

I only calculated the vertical component, the horizontal is 16 m/s

you need to find the resultant velocity by adding the vectors (using pythagorean theorem or the parallelogram way)

Edited by pimo
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