The average human requires 120.0 grams of glucose (C6H12O6) per day. How many grams of CO2 ( in the photosynthesis reaction) are required for this amount of glucose? The photosynthetic reaction is: 6 CO2 + 6 H2O = C6H12O6 + 6 O2
I'm having trouble putting the work into diminutional analysis
You look at the factor and make it so that the denominator is in the unit you start with and the numerator is the unit you want to keep. The numbers are the coefficients in the balanced equation.
For example, in the equation
H2 + Cl2 ==> 2HCl, if we start with 10 moles H2 and want to convert to moles HCl, we have
10 moles H2 x (2 moles HCl/1 mole H2) = 20 moles HCl. You notice that moles H2 cancel (that's what you started with) and it leaves moles HCl (what you want for the answer).
Your problem is a stoichiometry problem. Here is a worked example. Just follow the steps. Post your work if you get stuck.
http://www.jiskha.com/science/chemistry/stoichiometry.html
To find out how many grams of CO2 are required for the production of 120.0 grams of glucose, we need to use the stoichiometric ratio from the photosynthesis reaction.
According to the reaction:
6 CO2 + 6 H2O = C6H12O6 + 6 O2
We can see that 1 molecule of glucose (C6H12O6) is produced when 6 molecules of carbon dioxide (CO2) are consumed.
To find the molar mass of glucose (C6H12O6), we sum up the molar masses of its constituent elements:
C6H12O6:
6 carbon atoms (C) x atomic mass of carbon (12.01 g/mol)
12 hydrogen atoms (H) x atomic mass of hydrogen (1.01 g/mol)
6 oxygen atoms (O) x atomic mass of oxygen (16.00 g/mol)
Total molar mass of glucose (C6H12O6) = (6 x 12.01 g/mol) + (12 x 1.01 g/mol) + (6 x 16.00 g/mol) = 180.18 g/mol
Now, we can set up a ratio to calculate the grams of CO2 needed for 120.0 grams of glucose:
6 CO2 180.18 g glucose
------- = ---------------
1 glucose x g CO2
Cross-multiplying, we get:
6 CO2 * x g CO2 = 1 glucose * 180.18 g glucose
Simplifying the equation, we find:
6x = 180.18
Dividing both sides by 6, we get:
x = 30.03 grams
Therefore, approximately 30.03 grams of CO2 are required for the production of 120.0 grams of glucose in the photosynthesis reaction.