Which coefficient becomes your ratio?
Coefficients are ratios. Three moles of O2 in the hydrogen reaction make twice as much water. Learn to read the recipe.
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4 lessons for “Stoichiometry with mole ratios”
36 g of water: 2 moles or half a mole?
36.0 g of water is 2.00 mol, and 2.00 mol of CO2 is 88.0 g. Practice reading the units to choose divide or multiply.
Try this lessonWhy is a mole not a weight?
A dozen is 12. A mole is 6.02 x 10^23. Practice dividing particle counts by Avogadro's number, and learn why the mole is not a weight.
Try this lessonWhich reactant runs out first?
3.0 mol of O2 and 4.0 mol of H2: which runs out first? The ratio decides, not the smaller number.
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Is water's molar mass 17 or 18 g/mol?
The subscript 2 in H2O is easy to miss in a molar mass. Count it once, and every conversion after stays right.
Try this lessonWhich number goes first in a ratio?
Nia counted 10 bus riders and 6 walkers and wrote the ratio of walkers to bus riders as 5:3. She answered a different question than the one asked.
Try this lesson0.50 mol in 2.0 L: 0.25 M or 4 M?
Half a mole of salt in two liters of solution. Is the answer 0.25 M or 4 M? The definition settles it.
Try this lessonWhat is sin A when the opposite side is 3 and the hypotenuse is 5?
Trigonometry begins with one idea: a ratio of two sides. Label the sides for your chosen angle, and the ratio is mechanical.
Try this lessonHow much does one apple cost?
Ben paid $2.40 for 3 apples and divided 3 by 2.40, getting 1.25. He computed apples per dollar instead of dollars per apple.
Try this lessonIn a 30-60-90 triangle, what is the hypotenuse if the short leg is 5?
A 30-60-90 triangle has fixed ratios between its sides. Know one side and the other two follow without any trigonometry.
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