# Chemistry

Ok, I'm trying my best here, I'm learning, and I'm thinking I'm on a roll, until I can't get the right answer again.....

First.. the butane question

Calculate the mass of Butane needed to produce 82.7g Carbon dioxide.

2C4H10 +13 O2--->10H2O +8CO2

Ratio is 2 C4H10 to 8 CO2
82.7 g/molar mass of CO2 44 = 1.88g/mol
1.88 ( 2/8) = .47 and then .47 *58.12 = 27.3 I figured it out.. got the right answer .. But now on the next question it's asking for how many grams.. I'm confusing myself??

4Na+O2-->2Na2O

How many grams of Na2O are produced when 19.2 g. of Na reacts?
I started by getting moles..
19.2/22.9=.84 mols Na
.84(4/2)=1.68 then I did 1.68 *61.8 (molar mass of Na2O) and that was not the right answer... UGH!!! the right answer is 25.9 g somehow, and I can't figure out how.?

1. 👍 0
2. 👎 0
3. 👁 338
1. You stuck in numbers with the Na2O question without showing the units and you reversed the factor. The units are not there and that's why you can't find the error.
First I would not have rounded the 0.84 but kept 0.838. Why throw a perfectly good digit away. You have three digits in 19.2 so you should keep at least 3 in the answer. In fact, I usually keep an extra digit (as a guard digit) so I just leave that value in my calculator as 0.8384 and multiply that by the conversion factor.
0.8384 mols Na x (2 mols Na2O/4 molls Na) and that x (62 g Na2O/mol Na2O = about 26 grams. THEN you count the digits and round to the right number of significant figures.

1. 👍 0
2. 👎 0

## Similar Questions

1. ### children's literature

“The clay ball you made won’t roll? Why do you think it won’t roll? What could you do to make it roll better?” These questions stimulate: • A. language development. • B. spatial learning. • C. developmental play. •

asked by bev on January 21, 2017
2. ### the exceptional child

physical disabilities affect young children's learning because: a.physical disabilities always affect thinking. b.cerebral palsy gets progressively worse. c. physical therapy takes time away from learning. d.their learning is

asked by Rashmi on September 14, 2012
3. ### english

A life skill is something you need to get along in the world. Lifeskills: Typing. Matching clothes. Driving. Learning to bank, and use a check book. Writing a letter. Reading. Learning to search with Google. Learning to use the

asked by bobpursley on May 17, 2007
4. ### AP Biology

The type of learning that is involved in predator/prey interactions where an alteration in behavior is a response to stimulus is called...? -Habituation Learning? -Cognitive Learning? -Instinctive Learning? -Associative Learning?

asked by Lisa on August 1, 2010
5. ### AP Biology

They type of learning that is involved in predator/prey interactions where an alteration in behavior is a response to stimulus is called A. Habituation Learning B. Cognitive learning C. Instinctive Learning D. Associative Learning

asked by Allison on August 2, 2010
1. ### AP Biology

The type of learning that is involved in predator/prey interactions where an alteration in behavior is a response to stimulus is called? A. Habituation Learning B. Cognitive Learning C. Instinctive Learning D. Associative Learning

asked by Rachel on August 1, 2010
2. ### MATH

Two brands of paper towels are priced and described like this: Brand A: 100 sheets per roll for \$1.20 a roll. Brand B: 60 double sheets per roll for \$1.44 a roll. Which brand’s roll has the most “towel” for the money?

asked by meshelle on December 5, 2008
3. ### overview of teaching techniques

how should students be grouped to best encourage learning? (a)according to same abilities (b)according to same attitudes (c)according to same interests (d)according to a common task (my answer) which of the following types of

asked by susue on August 25, 2011
4. ### statistics

The below table shows the probabilities generated by rolling one die 50 times and noting the up face. What is the probability of getting an odd up face? roll 1 Probability 0.22 roll2 probability 0.10 roll 3 probability 0.18 roll 4

asked by sc on May 3, 2012
5. ### educating young children PART3

which one of the following guidelines is recommended when instructing children with learning differences? (a)begin with the childs preferred way of learning (b)use a task-analysis to break down complex tasks into their component

asked by susue on September 15, 2011
6. ### math

Consider a simple game in which you will roll a six-sided die and receive \$3.00 if you roll a 6. If it costs you \$0.90 for each roll, what is the expected value?

asked by Tara on January 5, 2011

More Similar Questions