Answer:
On the outside or something like that
six commonly recognised metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium. Five elements are less frequently so classified: carbon, aluminium, selenium, polonium, and astatine.
Answer:
B
Explanation:
The normal way to express an energy reaction is to put the energy on the left. Then you can make a rule.
- If the energy on the left is plus then the reactants require energy. The reaction is endothermic -- energy is taken from the environment.
- If the energy is minus when it is on the left. then the reactants give up energy. The reaction is exothermic and energy is given to the environment.
2CO(g)+O2(g) - energy --> 2CO2(g)
Exothermic
First, we will get the "n", the number of half lives, it is the elapsed time over the half life. In the problem, the time is measured in days, so we have
6/2 = 3
to get the ending amount of radioactive sample, we have
32g x (1/2)³ = 4 grams of radioactive sample ⇒ the amount left after 6 days
