How did Keplers discoveries contribute to Astronomy

a. they supported heliocentric model

b. they establish the laws of planetary motion

c. they explain how the sun rises and sets

d. they made astronomy assessable to people who spoke Italian

How many grams of magnesium metal will react completely with 8.3 liters of 5.5 m hcl? show all of the work needed to solve this problem. mg (s) + 2hcl (aq) → mgcl2 (aq) + h2 (g)

State one important difference between a physical change and a chemical change?

Select the correct value for the indicated bond angle in each of the compounds. o−o−oo−o−o angle of o3 90° 109.5° < 109.5° 120° < 120° 180° f−b−ff−b−f angle of bf3 180° < 109.5° < 120° 120° 109.5° 90° f−o−ff−o−f angle of of2 < 120° 120° 90° 109.5° 180° < 109.5° cl−be−clcl−be−cl angle of becl2 90° 109.5° 180° 120° < 109.5° < 120° f−p−ff−p−f angle of pf3 90° 109.5° < 109.5° 180° 120° < 120° h−c−hh−c−h angle of ch4 90° < 109.5° 180° 120° < 120° 109.5°