Why is it important to know gas properties at STP?

Which set of characteristics best describes igneous rock? a) largest type of rock, made of organic matter, hardest type of rock b) least abundant type of rock, made of other rocks, made mostly of minerals c) found on all continents, contains wavy bands of stripes, contains fossils d) most abundant type in earth's crust, made of magma/lava, contains no fossils

Classify this reaction: 2al+n2-> aln.

Identify arrows pointing to bonding electrons. done h-0-0-h ) intro