Questions posted in Chemistry - AssignmentGrade.com

Questions posted in Chemistry

Which state of matter contains the most energetic particles? A. gas B. solid C. liquid D. plasma

Plasma because it is a charged gas and the molecules are more free to move in a gas state.


ANSWERED AT 29/05/2020 - 05:24 PM


QUESTION POSTED AT 29/05/2020 - 05:24 PM

I don't know which one it is!

It's what you put :) 
ΔH is the distance from the reactants (which would be E), to the products (which would be G or D)

ANSWERED AT 29/05/2020 - 05:22 PM


QUESTION POSTED AT 29/05/2020 - 05:22 PM

1. Excision dermoid cyst of the nose, complex.

The answer is B ssss

ANSWERED AT 29/05/2020 - 05:22 PM


QUESTION POSTED AT 29/05/2020 - 05:22 PM

What is the volume of a cube that measures 2 cm on each side?

The answer is 8 centimeters cubed

ANSWERED AT 29/05/2020 - 05:19 PM


QUESTION POSTED AT 29/05/2020 - 05:19 PM

Is NI3 molecular or ionic?

Molecular compounds consists of 2 or more non-metals.
Ionic compounds consists of a metal and a non-metal. 
According to the periodic table, are N and I metals or non-metals?

ANSWERED AT 29/05/2020 - 05:18 PM


QUESTION POSTED AT 29/05/2020 - 05:18 PM

How many grams are in 3.00 mol of sodium chloride (NaCl)?

To switch from the amount of mols given to grams, we are going to have to first find out the molar mass of sodium chloride. 

ANSWERED AT 29/05/2020 - 05:14 PM


QUESTION POSTED AT 29/05/2020 - 05:14 PM

Assume a reaction takes place in a basic solution to form the given products: mno4-(aq) + cl-(aq) --------> mno2(s) + cl2(g) (unbalanced) i. Balance the given half reactions for atoms and charge

To balance, we write it in its half reactions and balance the half reactions by adding H2O, OH-, H+ and electrons. We do as follows:

MnO4-(aq) + Cl-(aq) --------> MnO2(s) + Cl2(g) 


2 (2H2O + MnO2 --> MnO4- + 4H+ 3e- )
3 (2e- + Cl2 --> 2Cl- )

4H2O + 2MnO2 -----> 2MnO4- + 8H+ + 6e- 
6e- + 3Cl2 -------> 6Cl- 
----------------------------------------------------------------------
4H2O + 2MnO2 + 3Cl2 --------> 2MnO4- + 6Cl- + 8H+ 

Since it is in a basic solution,

8OH- + 2MnO2 + 3Cl2 -----> 2MnO4- + 6Cl- + 4H2O 



ANSWERED AT 29/05/2020 - 05:10 PM


QUESTION POSTED AT 29/05/2020 - 05:10 PM

What kind of bond is a single covalent bond between a carbon atom and a sulfur atom?

Funny bone is the answer

ANSWERED AT 29/05/2020 - 05:09 PM


QUESTION POSTED AT 29/05/2020 - 05:09 PM

Two substances that have the same number of moles of representative particles always have: the same number of atoms the same masses the same weights None of these are correct.

Two substances that have the same number of moles of representative particles always have:
none of these are correct

ANSWERED AT 29/05/2020 - 05:07 PM


QUESTION POSTED AT 29/05/2020 - 05:07 PM

Why should pyrotechnicians worry about the yield of the reactants in a firework? How does the yield affect the firework and the environment?

The colors emitted by fireworks are products of chemical reactions. These products can be harmful to the environment, that's why, in other countries, it is prohibited to use fireworks, unless during New Year or Christmas. For example, blue fireworks from copper release cancerous dioxins, green sparks come from barium which is radioactive,etc.

ANSWERED AT 29/05/2020 - 05:03 PM


QUESTION POSTED AT 29/05/2020 - 05:03 PM

Which reaction produces the most energy per mass? fission fusion chemical ionization

The reaction which produce the most energy per mass is NUCLEAR FUSION. This is because, fusion involves the coming together of two nuclei; the binding energy that hold the nucleus together is very great. The complete conversion of one gram of matter in a fusion process will release 9*10^13 joules of energy. Fusion reactions have very high energy density which is many times greater than all other types of reaction.

ANSWERED AT 29/05/2020 - 05:02 PM


QUESTION POSTED AT 29/05/2020 - 05:02 PM

To achieve an octet of valence electrons, an iodine atom will become an ion with what charge?

The octet rule can be satisfied when there are 8 electrons in the valence shell. In other words, to be stable, it must follow that of the electronic configuration of the noble gases. Iodine has an atomic number of 53, while its nearest noble gas is Xenon (54). Thus, it needs one more electron to achieve octet rule. So, Iodine is usually present as I-1 in ionic form.

ANSWERED AT 29/05/2020 - 05:01 PM


QUESTION POSTED AT 29/05/2020 - 05:01 PM

Consider the chemical formula for calcium chlorate: Ca(ClO3)2 How many of each of these atoms is in a molecule of calcium chlorate? Ca: Cl: O:

The chemical formula for calcium chlorate is Ca(ClO3)2. Here the final number  indicates there is two of all inside the brackets. Therefore calcium chlorate has a single calcium atom, two chlorine atoms and six oxygen atoms. Calcium chlorate is often used as a herbicide to destroy vegetation that is not required or wanted. 

ANSWERED AT 29/05/2020 - 04:56 PM


QUESTION POSTED AT 29/05/2020 - 04:56 PM

Unsaturated hydrocarbons require a _____ to react.

It requires carbon and hydrogen to react

ANSWERED AT 29/05/2020 - 04:56 PM


QUESTION POSTED AT 29/05/2020 - 04:56 PM

How many AL(s) plus O2 is a balanced equation

27 of them





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ANSWERED AT 29/05/2020 - 04:53 PM


QUESTION POSTED AT 29/05/2020 - 04:53 PM

When the temperature of the air is 50°C, the velocity of a sound wave traveling through the air is approximately A. 50 m/s. B. 361 m/s. C. 30 m/s. D. 381 m/s.

When the temperature of the air is 50°C, the velocity of a sound wave traveling through the air is approximately Answer: 361 m/s

ANSWERED AT 29/05/2020 - 04:52 PM


QUESTION POSTED AT 29/05/2020 - 04:52 PM

Calculate the mass defect for the isotope thorium-234

Mass defect is defined as the difference or discrepancy between the mass of the nucleons and the mass of the nucleus. the nucleons involved are the protons and neutrons. 
mp  = 1.6727 x 10-24 g = 1.007316 amumn = 1.6750 x 10-24 g = 1.008701 amu
mTh 234 = 234 g/mol = 234 amu

Th234 (protons = 90; neutrons = 144)
mass defect = mp*90 + mn *144 - 234
mass defect = 1.911384 amu

ANSWERED AT 29/05/2020 - 04:50 PM


QUESTION POSTED AT 29/05/2020 - 04:50 PM

Which tool was most likely used in a procedure if the lab report shows that approximately 300ml of water was used

A graduated cylinder was used.

ANSWERED AT 29/05/2020 - 04:49 PM


QUESTION POSTED AT 29/05/2020 - 04:49 PM

What characteristics do atoms of argon-40, potassium-40, and calcium-40 have in common?

⁴⁰Ar
N(e)=18
N(p)=18
N(n)=40-18=22

⁴⁰K
N(e)=19
N(p)=19
N9n)=40-19=21

⁴⁰Ca
N(e)=20
N(p)=20
N(n)=40-20=20

ANSWERED AT 29/05/2020 - 04:48 PM


QUESTION POSTED AT 29/05/2020 - 04:48 PM

An egg is fried is that a physical or a chemical change

Chemical change.........................................................................

ANSWERED AT 29/05/2020 - 04:46 PM


QUESTION POSTED AT 29/05/2020 - 04:46 PM

A mixture of H2 and water vapor is present in a closed vessel at 20°C. The total pressure of the system is 755.0 mmHg. Partial pressure of water vapor at 20°C equals 17.5 mmHg. What is the partial pressure of H2?

The total pressure of a mixture of gases in a closed vessel is the sum of all the partial pressure exerted by each gas. This is in accordance with Dalton's Law of partial pressure. So, we can calculate as follows:

755 = P(H2O) + P(H2) = 17.5 + P(H2)
P(H2) = 737.5 mmHg

ANSWERED AT 29/05/2020 - 04:34 PM


QUESTION POSTED AT 29/05/2020 - 04:34 PM

Pcl5 exist but Ncl5 does not why?

Phosphorous have valence electrons in the 3rd energy level. It also have the 3d sublevel.

P 1s²2s²2p⁶3s²3p³3d⁰ → P* 1s²2s²2p⁶3s¹3p³3d¹

When the electron occupies the 3d sublevel, valence of phosphorus can be equal to five.

Nitrogen have valence electrons in the 2rd energy level. At the nitrogen atom, the 3d sublevel is absent.

ANSWERED AT 29/05/2020 - 04:33 PM


QUESTION POSTED AT 29/05/2020 - 04:33 PM

Which of the following elements has its highest energy electrons in an "s" atomic orbital? radiium (Ra) neon (Ne) aluminum (Al) lanthanum (La)

It would be the one that has the highest orbital level on the s suborbital which in this case would be Ra

ANSWERED AT 29/05/2020 - 04:28 PM


QUESTION POSTED AT 29/05/2020 - 04:28 PM

0.0136 g + 2.70 × 10-4 g - 4.21 × 10-3 g = ? How many digits to the right of the decimal point should be used to report the result?

The rule that applies in this evaluation is that in addition or subtraction operations, the answer (total/difference) should not be more accurate than the least accurate term. In this case, the number with least sig fig is 2.70 or 4.21. The answer here is 9.66 x10-3.

ANSWERED AT 29/05/2020 - 04:28 PM


QUESTION POSTED AT 29/05/2020 - 04:28 PM

Oxygen has 6 valence electrons. How many electrons does an atom of oxygen need to become stable?

Answer:

Two electrons

Explanation:

According to the octet rule, atoms must bond to each other, sharing electrons among themselves in an attempt to complete their valence shell (last layer of the electrosphere). In other words, an atom becomes stable when it has 8 electrons in its valence shell.

Oxygen atoms have six electrons in their valence shell, so to achieve the stability suggested by the octet rule (eight electrons), these atoms share two electrons, forming one oxygen gas (O₂) molecule.

ANSWERED AT 29/05/2020 - 04:27 PM


QUESTION POSTED AT 29/05/2020 - 04:27 PM

Select all that apply. Which of the following factors influence the electrical resistance of a circuit? conductivity of the material length of conducting wires diameter of conducting wires type of battery installed

conductivity of the material
length of conducting wires
diameter of conducting wires
type of battery installed
answer is d

ANSWERED AT 29/05/2020 - 04:27 PM


QUESTION POSTED AT 29/05/2020 - 04:27 PM

How is chemistry apart of daily routine

Chemical reactions takes place in plants and animals, this result in the formation of substances in some plants and animals that can be used to treat illness. Chemistryis important to everyday life, because it provides medicine. The food we consume each day comes directly from chemical processes.

ANSWERED AT 29/05/2020 - 04:19 PM


QUESTION POSTED AT 29/05/2020 - 04:19 PM