An impure sample of calcium carbonate (CaCO3) contains calcium sulfate as an impurity. When excess hydrochloric acid was added to
6g of the sample(CaCO3), 1200cm3 of gas (CO2) were produced
(measured at r. t.p.).
Calculate the percentage purity of the calcium carbonate sample.

Which compound contain an iron with a 3+ charge

Aglow stick contains a glass vial with chemicals. when the glow stick is bent, the vial breaks and the chemicals react to produce a glow. a science student observes that a glow stick kept in the freezer glows for a longer duration than a glow stick kept at room temperature. what conclusion can be drawn based on the observation? be sure to note the outcome and test variables in the conclusion.

Draw the aromatic compound toluene (methylbenzene). show all hydrogen atoms, including those on the ring.