# Chemistry Questions and Answers (Q&A) #### mmccoy

The correct answer to this question is C. Density is a physical property due the ratio between a substance's mass and volume. A physical property is something that does not change the chemical composition of the substance being observed. When you measure density, you place your subject on the scale to calculate mass, and then calculate volume by measuring the lengths and dividing the two.

Alternatively, you can measure density by using the displacement of liquid method, the volume of the liquid after the subject/object is immersed in the liquid, minus its original volume will give you substance's volume, then measuring mass on the scale. Since no chemical reaction is involved in measuring the density of a substance, it is considered a physical property. #### khartzler

I agree!! Can; water, can be separated by electorolysis :) #### I. Klose

The opposition that a substance offers due to the flow of electric current is called resistance. Resistivity is the electrical opposition per unit length, area, or volume of an element. Resistance contrasts with conductance, which is a measure of the ease with which electrical current flows through a substance.

The resistance of a substance is precisely proportional to the length of the material. The less conductivity, the higher the resistance there is. When electrons are propelled through a metal that has significant resistance, heat is generated, which is why the burner on your electric stove gets hot. A large amount of electricity is being pushed through a metal that has a high resistance, and it gets hot. #### khartzler

Carbon dioxide is a compound because it is two elements chemically combined. when there are number it most likely is a compound. #### kwchiro

The answer to this is letter C. You need to solve in order to get this answer. There are only two steps so you do not have to make a lot of effort to solve. The first step is to divide your grams and then divide by molar mass. This will become 118.082 grams divided by 39.1 grams. The answer will be 3.02 moles.

You are not done yet because you still have to do the second step. Change the moles to atoms by multiplying it with the Avogadros number. The equation will be 3.02 x 6. 02 x 10^23. You will get the answer for letter C which is 1.818 x 10^24 atoms. You can use the same formula when you are solving similar problems. #### jaukin.c

The process is endothermic. #### Wyatt Williams

Molecules are arranged in specific patterns in all materials. This is the basic theory of matter. These atoms are arranged in the specific manner because of the interconnecting bonds between the atoms. The stronger the bonds, the more tightly the atoms and molecules are held together.

This causes different states of matter. For instance, in solids, the molecules have tight chemical bonds between them. This causes the molecules to be tightly packed together and vibrating about their positions. In liquids, the bonds are weaker so the molecules are relatively free to glide about but are still close together. In gases, they are far apart. #### Wyatt Williams

20gX(1kg)/1000g = 0.020kg #### wchoi

The answer to this is C. If you would cover the end of the test tube with a paper towel, there is a big chance that the paper towel will also catch flames. If the liquid inside the test tube is flammable, the type of flames that it can form may be larger than usual. This can lead to some accidents inside the lab.

It is a good thing that students and professionals are always taught about the proper lab rules and regulations. Only people who would think that this can be done as a joke may try it out. All of the other choices are things that should be done while handling a test tube. #### Orion thames

I have read the word assumption used when describing certain subject s concerning scientific anolgies  