18.3Structure and General Properties of the Metalloids
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What this needs
Learn these first — this section will not make sense without them.
Nothing in the algebra book is a prerequisite for this section.
What this touches
Algebra that turns up here. Not a blocker, but this is where you will see it used.
- Applies1.6Rational Expressions
0.0923 g Si reacting to give 0.3030 g silicon sulfide requires converting both masses to moles and dividing by the smaller value to reach a whole-number ratio — the same reduce-to-lowest-terms move as canceling a common factor out of a rational expression, and rounding a ratio like 1.98 down to 1 instead of up to 2 gives the wrong empirical formula.
- Applies2.3Models and Applications
A silicon hydride at 306 torr, 26 °C, in 57.0 mL with mass 0.0861 g requires solving PV = nRT for n and then M = mass/n — the same substitute-then-solve-for-a-variable skeleton as any rate-and-quantity word problem, where using torr and °C directly instead of converting to atm and kelvin first throws the molar mass off by a large factor.