How many elements in the periodic table

1) Which of the following is the best example of a physical change? A) Sugar Dissolving in tea B) Firefly Glowing 2) In the combustion of ethane, what is/are the reactants? C2H6 + O2 = => CO2 + H2O A) C2H6 and O2 B) CO2 and C2H6

What is a atom and what do atom do in the world

Use the periodic table to identify the number of core electrons and the number of valence electrons in each case below. Potassium (K) : 1s22s22p63s23p64s1

Consider the following balanced reaction between hydrogen and nitrogen to form ammonia: 3H2 (g) + N2 (g) →2NH3 (g) How many moles of NH3 can be produced from 24.0 mol of H2 and excess N2?

What is the temperature of 12.2 moles gas in a 18.35 l tank at 16.4 atm? express in K and C.

Sodium and chlorine can bond together. sodium gives chlorine a needed electron. what is chlorine's charge after accepting the electron?

What astronomical equiptment did hypatia use?

Name each activity or observation as either physical or chemical change. 1) Boiling water for pasta 2) Digesting food 3) Soda goes "flat" 4) Stretching a rubber band 5) Grilling a hamburger 6) Adding sugar to tea 7) Adding lemon to tea 8) Mowing the

Ironing a shirt is an example of ... convection conduction radiation condensation

Which compound conducts electricity only in the molten state? A. sodium bromide B. calcium hydroxide C. barium sulfate D. magnesium sulfate