Answer:
- <em>The mystery substance is</em> <u>C. Bromine (Br) </u>
Explanation:
<em>Argon (Ar) </em>is a noble gas. Whose freezing point is -189 °C (very low), thus it cannot be the frozen substance. Also, it is not reactive, thus is would have not reacted with iron. Hence, argon is not the mystery substance.
<em>Scandium (Sc) </em>is a metal from group 3 of the periodic table, thus is will not react with iron. Thus, scandium is not the mystery substance.
Both <em>bromine</em> and <em>iodine</em> are halogens (group 17 of the periodic table).
The freezing point of bromine is −7.2 °C, and the freezing point of iodine is 113.7 °C. Thus, both could be solids (frozen) in the lab.
The reactivity of the halogens decrease from top to bottom inside the group. Bromine is above iodine. Then bromine is more reactive than iodine.
Bromine is reactive enough to react with iron. Iodine is not reactive enough to react with iron.
You can find in the internet that bromine vapour over hot iron reacts producing iron(III) bromide. Also, that bromine vapors are red-brown.
Therefore, <em>the mystery substance is bromine (Br).</em>
Explanation:
A substance burning in the presence of oxygen and leads to the formation of heat and light is called combustion.
Some important points about combustion are as follows:
- Fuel should be present for burning.
- Air should be present for the supply of oxygen.
- There should be heat (or ignition temperature) to initiate the chemical reaction.
Answer:
a generator that allows them to convert kinetic energy into potential energy
Explanation:
Rescue workers can accomplish this by using a generator that allows them to convert kinetic energy into potential energy. Such as a crank generator, with these, they spin a crank with their hands and the generator takes that kinetic energy that is building up through the work that the rescuer is exerting and converts it to potential electric energy that can properly be used to provide energy to the batteries for their equipment. This is what is generally used for situations such as what rescuers go through when there is no electricity around.
<span>Provide a direct contact between the oxidation and reduction electrodes - A</span>
Answer:
B.
Explanation:
Increased stability in fluoride ion.
