Questions posted in Chemistry

Let's go through each of the answers and think about why they work or don't work. 

Chemical forms compounds. 

Nuclear changes the element completely. We're going to use the sun as an example. The sun is in a state of plasma. It's really hot and has all these particles hitting into each other. The nucleus' of atoms are hitting into each other forming larger elements. It's real crazy. Nuclear is not correct. 

Physical cannot form a compound. 

Volume = mass / density

220.0g is our mass
55.0g/cm^3 is our density

(220g) / (55g/cm^3) = 4cm^3

Liquid into solid, gas into a liquid, gas into a solid (deposition).
Kinetic energy is all about motion. If you think about it, the particles are going from a more chaotic state to a more orderly arrangement which reduces the kinetic energy. 

The correct answer is electron-cloud model. This model states that electrons don't go around in an eliptical way but rather completely erratically and uncontrolably and this is why it can't be known where they are or how they will behave. They form sort of like a cloud of many electrons that move erratically so you have to check it to see where it is.

I did a quick search and found the diagram. Let's go through these and solve by elimination. 

B. Proteins can act as receptors which I guess could be considered a signal, but the rest of the molecules do not. B is incorrect. 

C. Lipids are not water soluble. An example of lipids are fats, and oils. Have you ever tried combining water and oil? Think about salad dressing, it does not mix. C is incorrect.

D. Carbohydrates and lipids are sources of energy, but nucleic acids and proteins are not. D is incorrect. 

The answer is A. because we know that our bodies are made up of nucleic acids, protein, fats, and we need carbohydrates in order to live normal, healthy lives. 

The molarity is moles/liters.

First, convert 4,000 mL to L:

4000 mL --> 4 L

Now, you must convert the 17 g of solute to moles by dividing the number of grams by the molar mass. The molar mass of AgNO3 is 169.87 g/mol:

17 / 169.87 = .1

Now that you have both the number of moles and the liters, plug them into the initial equation of moles/liters:

.1/4 = .025

It didn't change because nothing but the temperature to make it freeze went into it so it is still the same substance. Hope this helped!

The formulas indicate the number of elements in each compound. Notice the difference in ratios: 
NaCl is 1:1, while H2O is 2:1.

The question is asking the ratio of H to S in H2SO4.
In the following molecular formula, there are 2 hydrogen and 1 sulfur. 
This means that the ratio is 2:1.

Two things are given to us: The "molar mass" of NaOH and the number of molecules of NaOH. 

The molar mass is different from "mass"; 1 mole of NaOH is equal to 40.0g/mol.
When the question asks, what is the mass? It is referring to how many grams there are. 

First, we are going to convert the molecules to atoms using Avogadro's number (=6.02 x 10^23)

(2.50 x 10^22 molecules) x (6.02 x 10^23 atoms) = 0.042 mol

Next, we are going to convert from moles to grams.

 0.042 mol of NaOH x 40.0 g of NaOH/1 mole = 1.68g of NaOH.

There are 1.68 grams in 2.50 x 10^22 molecules of NaOH.

The membrane keeps the cell together and controls what goes in and out of the cell.

This is a weird question. 

Deserts do have very high day time temperatures, but they also have extremely low temperatures at night because of a lack of water. If you live in a city surrounded by water, you'll find that it will actually be warmer in the city at night than it would in a town further in-land. 

Explanation:

Number of moles consisting in a liter of solution is known as molarity.

Mathematically,       Molarity = \frac{\text{no. of moles}}{\text{Volume in one liter}}[/tex]

It is given that volume is 10 liter and there is 5.0 moles of solute. Hence, we will calculate the molarity as follows.

                 Molarity =

                                =

                                = 0.5 mol/L

Thus, we can conclude that molarity of the given solution is 0.5 mol/L.

The answer would be CaF2

We can observe physical properties of elements and compounds without changing the substance.

Examples of physical properties: Density, color, boiling point, state of matter, appearance: dull or shiny, etc. 

But we can also observe and measure chemical properties by reacting a substance with something else. For example, like mixing baking soda and vinegar together. The vinegar reacts with the baking soda and produces carbon dioxide: a new substance. 

Some examples of chemical properties: Flammability, amount of heat that is released during combustion, toxicity (how much damage it causes to other organisms), radioactivity, and ability to oxidize (when you have metal that becomes rusty looking).

it is called the Earth's rotation

The purpose of the analysis section of a lab report is to detail what happened in the lab and what the outcome of the project was as a result of said events.

observation

They utilize and make use of the scientific method in order to have clear basis and evidence for their investigations. Research method is always used to answer every scientific inquiry and in gaining evidential data or knowledge. The scientific method has the following process or at least undergoes the process of
1. Observation 
2. Hypothesis 
3. Experimentation 
4. Interpretation of data 
5. Evaluating the data 
6. Passing and recording the data 

These steps are crucial and the empirical data that these scientists obtain are very important to keep that is why research paper, thesis and dissertations exists.

There would be no way that the nutrients could go back into the ecosystem and there would be tons of dead animals lying around.

When gas molecules condence they become a liquid and if the liquid molecules condence they turn into a solid but the solid molecules cannot condence

Divide twenty-five by one thousand

Answer is Fluorine.
Hope it helps and pls mark as the best answer. :-)

a chemical compound

The energy produced by the reaction

Force its movement is force because of sent it in that direction

Electrons (negative charge, and orbits the nucleus), Protons (positive charge, and is in the nucleus) and Neutrons (no charge, and is in the nucleus)

Wheres the diagram

We have to see the diagram to answer your question

Because you need it to see if your looking at the right thing

Atoms are made of 3 types of subatomic particles that are electrons, protons and neutrons.
the number of protons in the atom is called the atomic number. the atomic number is characteristic of the element.
the mass number is the sum of the number of protons and neutrons. Since protons and neutrons both have similar masses and they are located in the nucleus, the mass of the atom is the sum of protons and neutrons.
Isotopes are when 2 atoms of the same element have different number of neutrons. Therefore atomic number is the same but mass number is different as the number of neutrons vary.

correct answer for the difference between isotopes is 
d)They have different numbers of neutrons and different mass numbers.

4x = -12

First, divide both sides by 4. / Your problem should look like: 
Second, since 4 goes into 3 to get 12, simplify it by 3. / Your problem should look like: 

Answer: x = -3