Answer:
b Different amounts of food samples were used.
Explanation:
The mass of the two samples needs to be the same in order for the test to be accurate.
Answer:
Described by a redox reaction below
Explanation:
Iron(III) oxide is an ionic compound, since it consists of a metal, iron, and a nonmetal, oxygen.
Ionic compounds are formed when metals lose their valence electrons in order to have an octet in their previous shell and donate them to nonmetal atoms, so that nonmetals fill their outer shell to have an octet.
As a result, positive ions (cations) and negative ions (anions) are formed. When iron reacts with oxygen, the following reaction takes place:
This is a redox (oxidation–reduction) reaction, since we have electron loss and gain. Four iron atoms lose a total of 12 electrons to obtain a +3 charge in the final compound, while 3 oxygen molecules gain these 12 electrons to become 6 oxide anions with a -2 charge.
The gas molecules move between the system and the surroundings follow PV=nRT.
<h3>What are molecules?</h3>
The smallest particle of a substance has all of the physical and chemical properties of that substance.
An increase in pressure pushes the molecules closer together, reducing the volume. If the pressure is decreased, the gases are free to move about in a larger volume.
In the kinetic theory of gasses, increasing the temperature of a gas increases in average kinetic energy of the molecules, causing increased motion.
The reduction in the volume of the gas means that the molecules are striking the walls more often increasing the pressure, and conversely if the volume increases the distance the molecules must travel to strike the walls increases and they hit the walls less often thus decreasing the pressure.
At constant temperature and pressure the volume of a gas is directly proportional to the number of moles of gas. At constant temperature and volume the pressure of a gas is directly proportional to the number of moles of gas.
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When a solid turns into a liquid
Example: Ice cube melts into water
Answer: Nitrogen
Explanation: Nitrogen has an atomic number of 7 and an atomic mass of about 14 u
