Pennies used to be made of copper and zinc and had a mass of of 3.1 g. Today pennies are made of copper-platted zinc and have a mass of 2.5 g. A new penny's mass is what percent of an old penny's mass?

The palm tree with island is a population or biome or community

A centrifuge was used to separate a sample into its components. What conclusion about the sample can be formed based on the technique used? It was a pure substance. It was a compound. It was a heterogeneous mixture. It was a homogeneous mixture

Someone getting ready to do a bungee jump is demonstrating this type of energy.

Choose all the answers that apply. Earth's water: is reused and recycled is mostly freshwater is strongly attracted to other materials has a neutral pH value can dissolve more substances than any other liquid

The angle at which light strikes a surface is the same as the angle at which it is reflected. true or false

Tina has a sample of gaseous water at a temperature of 400 C and a pressure of 4 atm. If Tina increases the pressure to 200 atm, will the gaseous water liquefy? Why or why not?

Label the molecular shape around each of the central atoms in the amino acid glycine. hint

Which has more atoms, 2moles of carbon or 2 moles of aluminum

At 100 degrees c, water reacts with acetic anhydride to make acetic acid. also, at 100 degrees c, water reacts with acetylsalicylic acid and reverts it to salicylic acid and acetic acid.

What is the valence electron configuration of the group 2a elements?