Why were metals such as copper and gold discovered long before gases such as oxygen and nitrogen?

A sample of 1.000 g of a compound containing carbon and hydrogen reacts with oxygen at elevated temperature to yield 0.692g H2O and 3.381g CO2. a. Calculate the masses of C and H in the sample. b. Does the compound contain any other elements

Select all that apply to the property of hardness. Hardness is a physical property Hardness is indicative of the strength of chemical bonds between elements. Hardness is determined through a complicated process that requires expensive instruments.

A sample of metal has a mass of 23.04 g, and a volume of 5.31 ml. what is the density of this metal?

Is glass etching a chemical change

When acetylene, C2H2, a fuel used in welding, is burned in air, two molecules of acetylene combine with five oxygen molecules to form four CO2 molecules and two H2O molecules. Select the statement below that is incorrect in regard to this reaction.

Why do the chemical properties cycle through each period? Every eighth element starting with hydrogen restarts the transition from metal to inert gas. Elements with atomic numbers which are multiples of eight start a new period.

Which statement correctly describes the Ka of a weak acid? The Ka is large, and the equilibrium favors products. The Ka is large, and the equilibrium favors reactants. The Ka is small, and the equilibrium favors products.

True or False? The fatal 1930 incident in Muese Valley, Belgium, was associated with leakage of toxic chemicals from a former dump site.

How many moles of neon (Ne, 20.179 g/mol) are in 68.4 grams of neon

A 50.00 mL sample of groundwater is titrated with 0.0300 M EDTA. Of 12.40 mL of EDTA is required to titrate the 50.00 mL sample, what is the hardness of the groundwater in molarity and in parts per million of CaCO 3 by mass