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A compound has a molar mass of 42.0 g/mol and the emperical formula is CH2{“version”:”1.1″,”math”:”2″}. What is the molecular formula?

A 52.8 g gold nugget is dropped into a graduated cylinder containing 50.00 mL of water and the level of the water rises to 52.80 mL. What is the density of the gold? (use the correct number of significant figures) _______ g\mL

What is the result of the following multiplication expressed in scientific notation to the correct number of significant figures?(2.13 x 108)(7.0 x 10-8)

If you start with 2.0 grams each of N2 and H2, how much NH3 could be produced according to the balanced equation N2(g) + 3 H2(g)–> 2 NH3(g)   (report the answer using 2 significant figures) _______ grams

What is the formula for hydrobromic aicd _______ .

An unknown element X forms a compound with the formula Al2X3.  X forms an ion that has 36 electrons.  What is the identity of X?  _______ .

Racing cars at the Indianapolis Motor Speedway  travel around the track at an average speed of 275 mi/hour. What is this speed in kilometers per hour? (use the correct number of significant figures) 1 m=1.094 yd;  1 mi=1760 yd _______ kilometers/hr

The molar mass of calcium phosphate, Ca3(PO4)2 is

In the atmosphere nitrogen dioxide gas reacts with water to produce nitrogen monoxide gas and nitric acid. What is the correct unbalanced equation for this reaction?

The length of the nail should be recorded as