1. Journal #21 Calculate the number of protons, neutrons and electrons for the following elements: – Carbon-14 – Helium – Iron (Fe)

2. Today, We will calculate the densities of various samples.

3. King Leo and His Crown King Leo was give a golden crown from the people in his kingdom. He wondered if the crown was indeed real gold or fake gold. He knew that if his people gave him a real golden crown, then he had their love and support. However, if it was fake gold then he knew that he needed to work harder to gain their support. How can he know for sure that the crown is real without damaging the crown?

4. Solution King Leo went to his advisor and asked him for help. His advisor took the crown and made an identical copy out of real gold. He weighed both crowns (to get a mass). He placed both crowns in water to measure the volume. The crown copy had a density to be 19g/mL

5. Conclusion The copied crown also a density equal to 19. Therefore, the crown given to King Leo was real gold!!

6. What is Density? The density of a substance is the relationship between the mass of the substance and how much space it takes up (volume).

9. Video https://www.youtube.com/watch?v=SimFy9w OMXY

10. Calculating Density

11. Practice: If a mineral sample has a mass (m) of 85 grams and a volume (V) of 34cm 3. Use the equation to calculate a sample’s density. Answer: Density = mass / volume Density = 84 / 34 Density = 2.5

12. Practice If a mineral sample has a mass (m) of 45 grams and a volume (V) of 12 cm 3. Use the equation to calculate a sample’s density. Answer: Density = mass / volume Density = 45 / 12 Density = 3.75

13. What is density

14. Calculate Density Mass = 20g Volume = 30mL

15. Calculate Density Mass = 10g Volume = 21mL