The half-life for the radioactive decay of calcium-47 is 4.5 days. how many half-lives have elapsed after 27 days?

An atom whose valence electrons conform to the octet rule is: A. More likely to form covalent bonds b. Form ionic bonds c. Form hydrogen bonds d. Less likely to form any bond

A student calculated the density of a sample of graphite to be 2.3 g/cm3. Show a numerical setup for calculating the student's percent error for the density of graphite.

A candy bar has a total mass of 75.0 grams. In a calorimetry experiment, a 1.0-g sample of this candy bar was burned in a calorimeter surrounded by 1000g of water.

A gas has a pressure of 0.410 atm and volume of 32 L. At what pressure, would the volume of the gas change to 28 L

If a sample contains 21.2 g N, how many moles of N does it contain? 0.66 mol 1.51 mol 14.01 mol 297.01 mol

Which describes the volume of 1 mol of gas at standard temperature and pressure? ER The volume is greater for a larger mass of gas. The volume is the same for any gas. The volume depends on the size of the container.

When studying historical geology, which type of rock provides the most useful evidence for uncovering what occurred? metamorphic igneous basalt igneous granite sedimentary

Calculate the molar solubility of ca (io3) 2 in each solution below. the ksp of calcium iodate is7.1 * 10-7.

At normal temperature and pressure, air has a density of 0.001184 g/mL. What is the mass of air in a room that is 3.07 m by 3.00 m by 3.77 m? Answer in units of kg.

A gas made up of atoms escapes through a pinhole 0.155 times as fast as h2 gas. write the chemical formula of the gas.