The electron dot diagram for a neutral atom of chlorine (atomic number 17) is shown below. Which of the following symbols represents a chlorine ion with a stable arrangement of eight valence electrons?
A. 35Cl1-
B. 35Cl2-
C. 35Cl1+
D. 35Cl

Modern pennies are composed of zinc coated with copper. a student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coaling (to expose the underlying zinc). the student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the hcl (the copper remains undissolved): zn(s) + 2 hcl(aq) → h2(g) + zncl(aq)the student collects the hydrogen produced over water at 25 °c. the collected gas occupies a volume of 0.899 l at a total pressure of 79 j mmhg. calculate the percent zinc (by mass) in the penny. (assume that all the zn in the penny dissolves.)

Why does earth rotate? because earth is formed from cold gases collapsing due to gravity because the matter in the nebula that formed earth was spinning because earth forms more than 99% of the mass of the solar system because the hydrogen atoms inside the nebula fused to form helium

To find the enthalpy of a reaction in the lab, you measured the of the reactants and the change during the reaction.