# Search results

1. ### Chemistry review questions-calculations

^ Oh, ok thanks for all your help!
2. ### Chemistry review questions-calculations

4. M=Mol/vol M= 0.2mol/2.0L M=0.1mol/L *** The teacher said we should only balance with whole nubbers so would it be 2H2 + O2 = 2H2O....? moles of H 0.22 mol sooo... moles of O is also 0.11mol? c)calculate the number of moles of water produced when 4.00 g of oxygen are used 2H2 + O2 = 2H2O...
3. ### Chemistry review questions-calculations

Hi, I have some reviw questions for the upcomming chemistry exam, the problem is I don't have the answers so can some one read throught my work and check if it is wright? Thanks. *** 1. An anaysis of a valitile liquid shoed that it wsa composed of 14.4%C, 2.37% H and 83.49% Cl. If 4.25 g of...
4. ### Pleas help! exam tommarow Trigonometry word problems

Pleas help! exam tommarow!!!! Trigonometry word problems Hi, i really need help with this question, on a wall, a spider is 100cm above a fly. the fly starts moving horizontally at the speed of 10cm/s. After 1s, the spider begins moving at twice the speed of the fly, in such a way as to...
5. ### Sequence and series word problem

Its supposed to be sequences and series so what I was doing was finding the % of medicnin that was in his body, but I guess this approach was wrong So I have to find the amount of medicin that is in his body So... t0=5oomg t1=625mg t2=656.25 Then tn-1 x 0.25+500 would be the recursave fomula
6. ### Sequence and series word problem

Tod injured his wrist while he was skateboarding. To relive the pain his doctor prescribed him some medication. He takes 500mg of medicine every 6h. Only 25 % of the medication remains in his body by the time he is ready to take another pill. Write and equation to model this. so 25% is...
7. ### Counting backwards; Sequences

1. are you sure? the answer in the back of the book sayes it is 34 and i cheked it again. _____________________________________________________________ 2. ok, thanks _______________________________________________________________ 4. the sum of 50 consecutive even intergers is 3250. tha...
8. ### Counting backwards; Sequences

Please help I have ALOT of questions!! 1.)Starting at 888 and counting backward by 7, a student counts 888, 881 and 874, and so on. Which of the following numbers will be included? a) 35 b) 34 c) 33 d) 32 e) 31 Ok, so I by using the calcuator the aswer is 34, but how would you calcuate...
9. ### Arithmetic series

^ ok, thanks for all your help
10. ### Arithmetic series

OK, these questions are supposed to be really easy, but I keep geting the wrong answer and I don't understand why, could someone pleas look at my work and tell me what I am doing wrong? Find the indicated sum of each arithmetic series S15 for 4 + 11 + 18 + ... Sn= n/2 [ 2a + ( n - 1 ) d...
11. ### Iron ore extraction

The cost of extracting and purifying metals is varied for various reasons, this means that the company might not make profit on the iron ore. Since there is a ,relatively, large amount of iron ore it is cheap. This means that the company needs to find a lot of it in order to make a profit. If...
12. ### Writing equations

so Fe2O3 + 3CO = 2Fe + 3CO2 Is this right?
13. ### Iron ore extraction

^ sorry I ment enviromental. Thanks for all your help!
14. ### Iron ore extraction

^ Ok thank you, so no marks taken off by saying there are no positive economic impacts if i explain..right?
15. ### Iron ore extraction

I really don't know what catagoir this would go under :confused: , but its an assignment for chem so... Woud there be any positive envromental impacts of iron ore extraction? This was on of the topics we had to reaserch, but form 3 days of searching throught the net, positive effects iron ore...
16. ### Writing equations

^ so would it be like this Fe3O + CO = 3Fe + CO2
17. ### Writing equations

Carbon monoxide reacts with the iron (lll) oxide. Would it be like this... 3Fe2 O3 + CO= 2Fe3 O4 + CO2
18. ### Neutralization calculations

A student obtains 25.00 mL of an HCl solution of unknown concentration. Upon titration, 21.35 mL of 0.1200 M NaOH are required for neutralization. Determine the concentration of the HCl solution. the capital M is molar mass right? but i thught that was constant so how can it be 0.1200 M NaOH...
19. ### Quick question-precipitate

when all the products are reatants are soluble there is no precipitate right?
20. ### Problem Solving question with circles

1.what is the equation of the largest circle that can be incribed in a square of side length 9 units, if the diagonals of the square intersect at (-1,3). where the radious is 9, but the ansewer in wrong *** 2.Todd is flying his radio-controilled airplane abouve the ground in a circular path...
21. ### Write an equation for the circle

k thanks for you help
22. ### Write an equation for the circle

ya, the book is old maby that answer is wrong. root 25 is 5 soo.. 5root2?
23. ### Write an equation for the circle

^ thanks I thought the two numbers were 25 and ...but how do you rght that? 2root25 simplify es to 2root5, but thats wrong right? the answer in the book was x^2+y^2=49
24. ### Write an equation for the circle

Hi, I need help with these questions Given the endpoints of a diameter, write an equation for the circle. a) (-3,5) and (1,3) I tryed this m= (x1+x2)/2, (y1+y2)/2 = (-3+1)/2 , (5+3)/2 = -2/2, 8/2 = (-1,4) ( x-h)^2 + (y-k)^2=r^2 (x+1)^2 + (y-4)^2=r^2 (1+1)^2 +...
25. ### Pleas help! Chemistry calculations

and I have another question If 3.45 x 10^23 formula units of Hg(NO3)2 are reacted with excess of Na2S, what mass of HgS can be expected if this process occurs with 97% yield? What are fomula units? you would do that question the same way as the previous one right?

^ ok, thanks
27. ### Pleas help! Chemistry calculations

^ Thanks #mols of C6H6 n=m/M n=12.8g/78.06g/mol n=0.164mol #mols of C6H5NO2 =0.164mol(0.70) =0.1148mol mass of C6H5NO2 m=nM m=0.1148mol(123.06g/mol) m=14.1g Like this?
28. ### Periodic function problem

f(7)=-2 f(7)=(7+12+12+12) =f(43) so f(43)=-2 is that right, what about f(11)? or do i not need to use that?
29. ### Periodic function problem

^ I don't get it can u show me an example? or would it be like this f(x)=f(x+na) f (43)=f(7+12(-2)) f(43)=-17
30. ### Pleas help! Chemistry calculations

the folowing reaction proceeds with a 70% yeild C6H6 + HNO3 = C6H5NO2 + H2O calculate the mass of C6H5NO2 expected if 12.8g of C6H5 reacts with excess HNO3 How do you do this problem?