Os-182 has a half-life of 21.5 hours. How many grams of a 10.0 gram sample will remain after exactly three half-lives?

Two friends at different locations want to communicate with each other by sending low energy signals. which of the following methods can they use to communicate? a) produce x-rays using colliding electrons and send them to radios, which capture sound b) send messages using infrared radiation, which travel in the form of waves c) send radio waves through intervening media like radio and television d) produce sound waves using microwaves from heated objects

Needthe meter is the standard unit for: 1) height 2) length 3) weight 4) mass

Summarize possible ways in which phases of matter could combine to form a solution.