Write the chemical symbol for the species described by the following: its parent element has atomic number 15 and mass number 31, and lost 3 electrons.

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.

Avariable that is not being directly tested during an experiment should be

How many moles in .5g of sodium bromide?