How many Ethers were in existence at launch and why? 1. 21 million because they wanted to have more units than Bitcoin 2. 72 million because they couldn't make any less 3. 72 million because they needed to raise cash for its development 4. 21 million because they needed some to use on the testnet

The molecular weight of carbon dioxide, co2, is 44.00 amu, and the molecular weight of nitrous dioxide, no2, is 46.01 amu, so no2 diffuses co2

If a sample of radioactive isotopes takes 600 minutes to decay from 400 grams to 50 grams, what is the half-life of the isotope?

Suppose a pair of chemical compounds a and b can react in two different ways: a + b -> c reaction 1 gives product c. a + b -> d reaction 2 gives product d. the following facts are known about the two reactions: . reaction 1 is endothermic and reaction 2 is exothermic. if a reaction vessel is charged (filled) with a and b , then at first d is produced faster than c. use these facts to sketch a qualitative reaction energy diagram for both reactions. note: because these sketches are only qualitative, the energies don? t have to be exact. they only have to have the right relationship to each other. for example, if one energy is less than another, that fact should be clear in your sketch.