A weighed piece of magnesium ribbon is added to a dried crucible, which is reweighed and heated in air to form the compound MgO. The crucible is cooled and reweighed to find the mass of MgO. Which error could lead to a mass percentage of magnesium that is too low?

During trial 2, what allowed you to determine that aluminum was the limiting reactant? check all that apply. all of the copper dissolved. all of the aluminum dissolved. the solution turned clear. the number of grams of copper(ii) chloride used in the reaction was greater than the number of grams of aluminum. the molar ratio of copper(ii) chloride to aluminum was greater than 3: 2, the equation’s molar ratio.

When water dissociates, each water molecule splits into a hydroxide ion and a) h 3 o + b) a hydrogen atom c) a hydrogen ion d) h 2 o e) oh —

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.