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.
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2 lessons for “Molar mass”
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.
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0.50 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 happens when cold air meets warm air?
You said a front is a wall of dark cloud. A front is the moving boundary between two air masses; clouds and storms gather along it.
Try this lessonWhy isn't the mass number just the neutrons?
An atom with 17 protons and 18 neutrons: is its mass number 35 or 18? And what is its charge? Work through the counting rules one blank at a time.
Try this lessonWhere does a growing plant's mass come from?
You said the soil feeds the plant. Soil holds water and minerals, but most of the tree's wood is built from carbon in the air.
Try this lessonDoes heavy mean it sinks?
You said the steel ship is too heavy to ever float. The ship's average density, steel plus the air inside it, is less than water, so it floats.
Try this lessonWhy can't you balance by changing H2O to H4O2?
Water is H2O, not H4O2. Learn how coefficients balance an equation without inventing new molecules.
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