CHEMAT 7-8 C Multiple Choice answers the question. Idenniti the choice that best
ID: 519784 • Letter: C
Question
CHEMAT 7-8 C Multiple Choice answers the question. Idenniti the choice that best completes the statement or A 1. One mole is defined as the number of particles equal to the number of atoms in exactly 12 g of carbon-12. the number of particles equal to the number of atoms in exactly g of oxygen 16. 16 d 6.02 x atoms in exactly Igof hydrogen-1. National the number of particles equal to the number of 1 kg of carbon at the e, the number of particles equal to the number ofatoms in exactly 2. A gallon of water a mass of 3.79 kg. How many moles of water (802 g mol) is this? has mol d. 68.300 a, 0.210 mol 386 mol lb. 210 mol c. 683 mol Which of the following contains the largest number of atoms? a. I mol water b. I mol phosphorus trichloride c. 1 mol dinitrogen pentoxide d. 2 mol carbon monoxide same number of atoms. e. All of these contain the 4. How many atoms of chlorine are there in 25.0 gofealcium chloride (CaCI)? 2.71 x 10 atoms a, 1.36 x 10 atoms 1.95 x 10 atoms b, 2.67 x 10 atoms reactants 5. Hydrogen peroxide to produce water and oxygen. relationship regarding the quantities of decomposes Which and products associated with this reaction is not correct? a. 68.0 g 36.0 g 32.0 g b. 34.0 g 18.0 g 16.0 g 90,4 g 47.9 g 42.6 g 6 Feros(s) and powdered aluminum can react with great output of heat to form molten iron and Alro, when this reaction equation is balanced. what are the stoichiometric coefficients in the following order: Fero, Al, Fe, Alao? d. 2. I, 1,2 a. 1, 1, 1, I e. 1, 1,2, 2 b, 2, 2, 2, 2 c. 1, 2, 2, 1 7. reacts water to form bydroxide (oH), and oxygen (o). What the sum of iodine is the stoichiometric coefficients in the balanced reaction equation?Explanation / Answer
Answer:
12. d- 6
Explanation:
A molecule with molecular weight of 180.18 g/mol is analyzed and found to contain 40.00% carbon, 6.72% hydrogen and 53.28% oxygen.
What are the empirical and molecular formulas of the molecule?
How To Find the Solution
Finding the empirical and molecular formula is basically the reverse process used to calculate mass percent.
Step 1: Find the number of moles of each element in a sample of the molecule.
Our molecule contains 40.00% carbon, 6.72% hydrogen and 53.28% oxygen. This means a 100 gram sample contains:
40.00 grams of carbon (40.00% of 100 grams)
6.72 grams of hydrogen (6.72% of 100 grams)
53.28 grams of oxygen (53.28% of 100 grams)
Note: 100 grams is used for a sample size just to make the math easier. Any sample size could be used, the ratios between the elements will remain the same.
Using these numbers we can find the number of moles of each element in the 100 gram sample. Divide the number of grams of each element in the sample by the atomic weight of the element (from the periodic table) to find the number of moles.
moles C = 40.00 g x 1 mol C/12.01 g/mol C = 3.33 moles C
moles H = 6.72 g x 1 mol H/1.01 g/mol H = 6.65 moles H
moles O = 53.28 g x 1 mol O/16.00 g/mol O = 3.33 moles O
Step 2: Find the ratios between the number of moles of each element.
Select the element with the largest number of moles in the sample.
In this case, the 6.65 moles of hydrogen is the largest. Divide the number of moles of each element by the largest number.
Simplest mole ratio between C and H: 3.33 mol C/6.65 mol H = 1 mol C/2 mol H
The ratio is 1 mole C for every 2 moles H
Simplest ratio between O and H: 3.33 moles O/6.65 moles H = 1 mol O/2 mol H
The ratio between O and H is 1 mole O for every 2 moles of H
Step 3: Find the empirical formula.
We have all the information we need to write the empirical formula. For every 2 moles of hydrogen, there is one mole of carbon and one mole of oxygen.
The empirical formula is CH2O.
Step 4: Find the molecular weight of the empirical formula.
We can use the empirical formula to find the molecular formula using the molecular weight of the compound and the molecular weight of the empirical formula.
The empirical formula is CH2O. The molecular weight is
molecular weight of CH2O = (1 x 12.01 g/mol) + (2 x 1.01 g/mol) + (1 x 16.00 g/mol)
molecular weight of CH2O = (12.01 + 2.02 + 16.00) g/mol
molecular weight of CH2O = 30.03 g/mol
Step 5: Find the number of empirical formula units in the molecular formula.
The molecular formula is a multiple of the empirical formula. We were given the molecular weight of the molecule, 180.18 g/mol.
Divide this number by the molecular weight of the empirical formula to find the number of empirical formula units that make up the compound.
Number of empirical formula units in compound = 180.18 g/mol/30.03 g/mol
Number of empirical formula units in compound = 6
Step 6: Find the molecular formula.
It takes six empirical formula units to make the compound, so multiply each number in the empirical formula by 6.
molecular formula = 6 x CH2O
molecular formula = C(1 x 6)H(2 x 6)O(1 x 6)
molecular formula = C6H12O6
Solution:
The empirical formula of the molecule is CH2O.
The molecular formula of the compound is C6H12O6.
Note: as per chegg guidelines solve first question
13. b. water
14.e. 6M
15.a.0731g