How do you know if a chemical change has taken place?

You have 4.3 moles of fe2o3. how many grams is that?

When in a compound, the oxidation number of a nonmetal: A). is always fixed and can never be changed B). can only be deduced once all the other oxidation numbers in the equation are totaled C).

Which change occurs when an atom in excited state returns to ground state? 1 energy is emitted 2energy is absorbed 3 the number of electrons decreases 4 the number of electrons increases

what is the 'lightest halogen around'?

Does gold react with other chemicals easily

Which indicator will be the same color in hydrochloric acid as it is in pure water? 1. methyl orange 2. phenolphthalein 3. bromcresol green

Based on your knowledge of energy resources conservation, which of the following statements is true? a) Manufacturers can increase a light bulb's energy efficiency by using technology that decreases the amount of electromagnetic energy the bulb

Ammonia (nh3 (g), hf = - 46.19 kj/mol) reacts with hydrogen chloride (hcl (g), hf = - 92.30 kj/mol) to form ammonium chloride (nh4cl (s), hf = - 314.4 kj/mol) according to this equation:

How does an electromagnet create a magnetic field

Magnetism, reactivity, and fluorescence are three special properties used to identify minerals. true or false