Why has the atomic model changed over time

Calculate the mass of water produced when 2.64 g of butane reacts with excess oxygen.

You need to make an aqueous solution of 0.125 M barium chloride for an experiment in lab, using a 250 mL volumetric flask. How much solid barium chloride should you add?

Uranium-238 decays by alpha emission. What is the mass number of the resulting element?

How many moles of CH3OH are there in 43.7 mL of 0.400 M CH30

A chemist measures the energy change ΔH during the following reaction: 2HgO (s) → 2Hg (l) + O2 (g), ΔH = 182.0 kJ Use the information to answer the following questions. (1) This reaction is: a. endothermic. b. exothermic. (2) Suppose 72.

Periodic table, chemistry questions who discovered lanthanides. how did they discover it, when did they discover it.

A flask containing 155cm^3 of hydrogen was collected under a pressure of 22.5kPa. What pressure would have been required in order for the volume of the gas to have been 90.0 cm^3 at constant temperature?

Which change is most likely to occur when a molecule of H2 and a molecule of I2 collide with proper orientation and sufficient energy? 1. a chemical change, because a compound is formed 2. a chemical change, because an element is formed 3.

Which substance is a diatomic molecule? a. he b. o2 c. co2 d. h2o?

What is the difference between the electronegativity values of sodium and bromine?