Answer:
Most radio waves have wavelengths between 1 mm and 100 km.
A cooling curve shows A. how the temperature of a substance falls as heat is removed.
Explanation:
<em>Radio waves</em> are the longest of all the waves in the electromagnetic spectrum.
Most have wavelengths between 1 mm and 100 km, although there is no upper limit.
Some radio waves have wavelengths of 10 000 km.
A <em>cooling curve</em> (see image below) shows how the temperature of a substance falls as it is cooled.
In Option E., a decrease in temperature would cause an energy <em>loss</em>.
Options B., C., and D. involve the <em>addition of heat</em>.
Amphetamine was developed initially as a substitute for a closely-related chemical derived from the Chinese herb ma huang. That chemical is Ephedrine.
<h3>
What is Ephedrine?</h3>
Ephedrine is a stimulant medication that can be considered an amine chemical compound and substituted amphetamine.
Ephedrine is used in sports to stimulate the central nervous system (C_NS) and as energy supplier.
Ep_hedrine use is prohibited and chronic usage of this substance may have problems the health.
Learn more about Ephedrine here:
brainly.com/question/1122074
The answer is 60.3% magnesium, 39.7% oxygen.
Solution:
The chemical equation for the reaction is 2 Mg + O2 → 2 MgO.
Since magnesium reacts completely with oxygen, it is the limiting reactant in the reaction. Hence, we can use the number of moles of magnesium to get the mass of MgO produced:
moles of magnesium = 14.7g / 24.305g mol-1
= 0.6048 mol
mass of MgO = 0.6048mol Mg(2 mol MgO/2mol Mg)(40.3044g MgO/1 mol MgO)
= 24.376g MgO
We can now solve for the percentage of magnesium:
% Mg = (14.7g Mg / 24.376g MgO)*100% = 60.3%
We also use the number of moles of magnesium to get the mass of oxygen consumed in the reaction:
mass of O2 = 0.6048 mol Mg (1mol O2 / 2mol Mg) (31.998g / 1mol O2)
= 9.676g
The percentage of oxygen is therefore
% O2 = (9.676g O2 / 24.376g MgO)*100%
= 39.7%
Notice that we can just subtract the magnesium's percentage from 100% to get
% O2 = 100% - 60.3% = 39.7%
A coefficient is a whole number that appears before the formula in an equation.
11 with pemdas, you have to multiply all by 3
