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Potassium dichromate, K2Cr2O7, is used in tanning leather, decorating porcelain and waterproofing fabrics. Calculate the number of chromium atoms in 78.82 g of K2Cr2O7.

If a car makes 25.0 miles/gal, how many liters of gasoline are needed for a 322 km trip?   (1 mile = 1.609 km, 1 gallon = 3.79 L)

Which one of the following combinations of names and formulas is incorrect?

How many atoms of oxygen are in 126 g sample of carbon dioxide?

Classify each of the following elements as nonmetal, main group metal, transition metal or metalloid.

What is the most important characteristic of anole lizard species that keeps members of one species from mating with members of another species? A.   Different species live in different ecological niches. B.    Different species living in the same habitat have different dewlaps. C.    Different species have differences in appearance, such as color or leg length. D.   Different species eat different types of food.

What element is defined by the following information? 18 protons, 22 neutrons, 18 electrons

Ionic bond is formed by transfer of [1] from metal to [2]. [3] bond is when atoms [4] one, two or three pairs of electrons.

In [1] and liquids particles are close together. In [2] particles are far apart, so gases are compressible.

Calculate the atomic mass of fictional element “X”, if it has 2 naturally occurring isotopes with the following masses and natural abundances: X-45    44.8776 amu   32.88% X-47    46.9443 amu