How did early chemists determine which substances were elements?

a. by observing chemical reactions

b. by finding the atomic mass

c. by counting neutrons

d. by counting protons

What is the sideward emisson of light by illuminated molecules or particles?

Describe the reaction of a weak acid and a strong base. In general, what will the final pH be when the reaction between equal moles of a weak acid and a strong base is complete?

Which statements describe the six elements found in all living things? Check all that apply. Carbon is the basis of all living things. Sulfur is found in bones, where it provides strength. Nitrogen is found in certain foods.

1. If Styrofoam ball and a steel ball are the exact same size & shape: a. Describe the volume (which has more, or are they the same) :

How many hydrogen atoms are missing in ethane compared to ethane

Which of the following is a natural material? cement A) cement B) cotton C) polyester D) nylon

Which of the following would be the best conductor of heat energy? a plastic spoon a wooden spoon a metal spoon

J. J thomsons experiment disproved the theory that an atom A) is divisible B) is indivisible C) contains protons D) contains electrons

What is the maening of separation methods

Examine the equation. 6CO2 + __H2O C6H12O6 + 6O2 In order to balance the equation, what coefficient must be placed in front of H2O? 4 1 6 12