#4 #5 #174. If 12 g of carbon combine completely with 16 g of oxygen to form carbon monoxide, how many grams of carbon does it take to combine completely with 80 g of oxygen?
By ratios, we find
5. Given that 1 g of hydrogen combines completely with 8 g of oxygen to form water, how much water can you make with 16 g of hydrogen and 16 g of oxygen?
By conservation of mass, we know that combining 8 g of oxygen with 1 g of hydrogen gives 9 g of water. From the ratios, 16 g of oxygen will combine with 2 g of hydrogen to form 18 g of water. There will be 14 g of hydrogen left.
17. A woman with a mass of 50 kg is wearing shoes with heels that have a cross-sectional area of 4 square centimeters. What is the pressure she exerts on the floor when she is standing on one heel?
Using the definition of pressure as force divided by area, we get
