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.

Apeak with a retention time of 407 s has a width at half-height (w1/2) of 7.6 s. a neighboring peak is eluted 17 s later with a w1/2 of 9.4 s. a compound that is known not to be retained was eluted in 2.5 s. the peaks are not baseline resolved. how many theoretical plates would be needed to achieve a resolution of 1.5?

Write the empirical chemical formula of calcium with a mass percent of 38.8, phosphorus with a mass percent of 20.0, and oxygen with a mass percent of 41.3.

As you watch a surfer ride a wave towards the shoreline, what is the shoreline? a) displacement reference b) reference point c) coordinate plane d) cartesian boundary