The chemical symbol for sodium is
a. n.
b. s.
c. na.
d. sn. user: the most active of all the chemical elements is a halogen known as
a. iodine.
b. astatine.
c. bromine.
d. fluorine. user: dalton used the lightest element as his standard for atomic mass. what is this element?
a. carbon
b. nitrogen
c. hydrogen
d. oxygen

Which best describes how johannes kepler developed his laws of planetary motion

Read the chemical equation. 2c2h2 + 5o2 → 4co2 + 2h2o which of the following statements would be correct if one mole of c2h2 was used in this reaction? one mole of oxygen was used in this reaction. five moles of oxygen were used in this reaction. four moles of carbon dioxide were produced from this reaction. two moles of carbon dioxide were produced from this reaction.

When the chemicals iron sulfide (fes) and hydrochloric acid (hcl) are combined, bubbles appear from the mixture. 1. does the appearance of bubbles indicate a physical or chemical change? 2. why do the bubbles indicate this change? 3. what property is this?