Classify each of these samples of matter as an element, a compound , or a mixture. i need help with this please help me out.

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

Asyringe contains 56.05 ml of gas at 315.1 k. what volume will that gas occupy if the temperature is increased to 380.5 k? a) 12.41 b) 46.42 c) 67.68 d) 81.74

In the lab, ammonia was mixed with water to form ammonium hydroxide. what is/are the reactant(s)? o water and ammonia o ammonia o ammonium hydroxide need