Ingredients Needed • 4 Cups Flour • 2 Cups Sugar • 8 Tbsp Cocoa • 1 Cup Melted Butter • 2 Cups Milk • 4 Eggs • 1 Tsp Vanilla
Problem • A baker gets an order for 8 BIG Chocolate Cakes. The sous-chef looks in the stockroom to see if there are enough ingredients before heading to the store. • Based on his findings, will he need to go to the store? • If he needs to go to the store, what should he buy?
Stockroom Inventory • Sack of flour (40 cups) • 2 bags of sugar (each with about 30 cups) • ½ can of cocoa (full can has 100 Tbsp) • 2 dozen eggs • 4 boxes of butter (4 sticks, each stick ½ cup) • ½ bottle vanilla (full bottle = 60 tsp) • 4 gallons milk (1 gal = 16 cups)
Questions • How many BIG Chocolate cakes can be made? • If flour is left over, how much? • Does the sous-chef need to go to the store? • What does the sous-chef need to buy?
Chemistry Connection • In chemistry, we cannot see the individual ingredients… they are much too small! • We get “packages” of ingredients. • This is like receiving large boxes of cake ingredients and only knowing the masses of the boxes received. Could we calculate the number of cakes made? YES! As long as we know the masses of the individual particles.
Chemistry Connection Continued • If we know the dozar mass of eggs is 915.60 g/doz and the box received is 3434.23 grams, how many grams of cake could be made if the dozar mass of cake is 12,432.40 g/doz? • Sounds complicated. Let’s use dimensional analysis.
Must work in dozens for cake stoichiometry… in chemistry it will will be moles. • 1st factor: convert grams eggs to doz eggs. • 2nd factor: EXCHANGE dozen eggs for dozen cakes. • 3rd factor: convert dozen cakes to grams cakes. • 3434.23 grams EGs x _______x ________x ______grams CKs