Which of these would indicate a chemical change has occurred? a) salt is dissolved into water. b) a child colors a picture with a crayon. c) solid iron is heated until it turns into a liquid. d) a metal is added to an acid and hydrogen gas is formed.

Calculate: select the worksheet tab. this tab you calculate the analyte concentration.  fill in the first set of boxes ("moles h2so4" and "moles naoh") based on the coefficients in the balanced equation. (if there is no coefficient, the value is 1.)  record the appropriate volumes in the "ml naoh" and "ml h2so4" boxes.  record the concentration of the titrant in the m naoh box. click calculate. what is the concentration listed

6. using 3 – 4 sentences explain (in your own words) why water expands when it freezes? 7. using your knowledge of colligative properties explain whether sodium chloride or calcium chloride would be a more effective substance to melt the ice on a slick sidewalk. use 3 – 4 sentences in your explanation.

Describe the forces both attractive and repulsive that occur as two atoms move closer together.