A simple recreation of the Nestle Toll House Chocolate Chip Cookie recipe is as follows:
2 1/4 cups all - purpose flour
1 tsp. baking soda
1 tsp. salt
1 cup (2 sticks butter or margarine, softened
3/4 cups granulated sugar
3/4 cups packed brown sugar
1 tsp. vanilla extract
2 large eggs
2 cups NESTLE TOLL HOUSE Semi-Sweet Chocolate Morsels
1 cup chopped nuts
A) Baking soda consists mostly of a single chemical, sodium bicarbonate (NaHCO3). Look up the molecular weight and density of sodium bicarbonate, and determine the number of moles used in this recipe. Give your answer in moles but do not include the units.
I really need help with this question, I don't understand how I am supposed to determine the number of moles with just the density and weight.
volume of NaHCO3 ... 1 tsp = 4.93 cm^3
volume * density = mass
mass / molar weight = moles
oops. I should have divided by g/mole to make the units come out.
Go with R_scott's solution
To determine the number of moles of sodium bicarbonate (baking soda) used in the recipe, we need to use the given information about the molecular weight and density of sodium bicarbonate. Here are the steps to follow:
Step 1: Look up the molecular weight of sodium bicarbonate (NaHCO3).
The molecular weight of sodium bicarbonate is calculated by adding up the atomic masses of its constituent atoms:
Na (sodium) = 22.99 g/mol
H (hydrogen) = 1.01 g/mol
C (carbon) = 12.01 g/mol
O (oxygen) = 16.00 g/mol
Molecular weight of NaHCO3 = (22.99 g/mol) + (1.01 g/mol) + (12.01 g/mol) + (3 x 16.00 g/mol)
Step 2: Calculate the number of moles using the molecular weight and density.
Since we only have the molecular weight and density, we need to use the density to calculate the mass of baking soda used in the recipe. Then we can convert the mass to moles.
Density = Mass / Volume
From the recipe, we know that 1 tsp of baking soda is used. Let's assume the density of baking soda is 2.20 g/cm^3.
First, we need to convert the volume of 1 tsp to cubic centimeters (cm^3):
1 tsp = 4.93 cm^3 (approx.)
Now we can calculate the mass of baking soda used:
Mass = Density x Volume
Mass = 2.20 g/cm^3 x 4.93 cm^3
Finally, we can calculate the number of moles:
Number of moles = Mass / Molecular weight
Number of moles = (calculated mass in grams) / (molecular weight in g/mol)
So, by following these steps and performing the calculations using the density of baking soda and the molecular weight of sodium bicarbonate, you can determine the number of moles used in the recipe.
1 tsp = 4.93 cm^3
mol wt = 84 g/mole
density = 2.2 g/cm^3
Now just make sure that the units work out
2.2 g/cm^3 * 4.93cm^3 * 84g/mole = (2.2*4.93*84) moles