What are simple substances which cannot be decomposed by ordinary chemical means?

Which of the following is hydroxide ion?

True or False? Ammonium ion is a cation.

UCBA has computers (loaner laptops and on-site computers) that students may use to take exams. UCBA also has reliable WiFi and quiet places where students can take exams.   Please select the answer that best applies to you.

Consider the reaction of iron (III) oxide with carbon to form iron metal and carbon dioxide gas: 2 Fe2O3 (s) + 3 C (c) →  4 Fe (s) +  3 CO2 (g)            

Three separate 3.5 g blocks of Al, Pb and Cr are heated from 25°C is heated to 75°C. Which block requires absorbtion of the most amount of heat (q) to reach the final temperature?  

Consider an unknown metal sample that weighs 10.0 g. If the unknown metal absorbs 309 J of energy to heat up from 10.0°C to 27.0°C, what is the most likely identity of the metal?  

What is the oxidation number for the chlorine atom in the compound, potassium perchlorate, KClO4?

Three separate 3.5 g blocks of Sn, Hg and Cr are heated from 25°C is heated to 75°C. Which block requires absorbtion of the most amount of heat (q) to reach the final temperature?  

Consider the reaction where hydrogen gas reacts with bromine gas to form hydrogen bromide gas: H2 (g) + Br2 (g) →  2 HBr (g)