Which of the following can't be broken down by chemical change? Sulfuric acid, ammonia, water, or potassium.
Potassium can't be broken down by chemical change because it's an element, which is the simplest form of matter. Sulfuric acid, ammonia and water are all compounds composed of elements. Compounds can be broken down into simpler compounds or elements by a chemical reaction.
You can tell if a substance is an element or compound by its chemical formula. The formula for a compound show the elements of which it's composed. Here are the formulas for the substances in the question:
sulfuric acid: `H_2SO_4`
The formula for sulfuric acid, for example, shows that it contains the elements hydrogen, sulfur and oxygen. During a chemical reaction bonds between the atoms in a molecule are broken.
Elements are made of atoms, which are the smallest particles of matter that retain the properties of that matter. An atom can be broken down into smaller particles in a nuclear reaction, but the sub-atomic particles that result are identical regardless of the type of atom from which they came. In other words, every gold atom has the properties of every other gold atom but a proton, neutron or electron from a gold atom is no different than any other proton, neutron or electron.
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