Questions posted in Chemistry - AssignmentGrade.com

Questions posted in Chemistry

Calculate the mole fraction of the total ions in an aqueous solution prepared by dissolving 0.400 moles of MgBr2 in 850.0 g of water

Answer : The mole fraction of the total ions in an aqueous solution is 0.0248

Explanation :

First we have to calculate the moles of water.

\text{Moles of water}=\frac{\text{Mass of water}}{\text{Molar mass of water}}=\frac{850.0g}{18g/mole}=47.22moles

Now we have to calculate the moles of magnesium ion and bromide ion.

As we are given that 0.4 moles of MgBr_2 that means, there are 0.4 moles of magnesium ion and 0.8 moles of bromide ions.

Total mole of ions in an aqueous solution = 0.4 + 0.8 = 1.2 mole

Now we have to calculate the mole fraction of the total ions in an aqueous solution.

\chi_{\text{(Total ions)}}=\frac{n_{\text{(Total ions)}}}{n_{\text{(Total ions)}}+n_{water}}

\text{Mole fraction of total ions in an aqueous solution}=\frac{1.2mole}{1.2mole+47.22mole}=0.0248

Therefore, the mole fraction of the total ions in an aqueous solution is 0.0248

ANSWERED AT 01/04/2020 - 01:47 PM


QUESTION POSTED AT 01/04/2020 - 01:47 PM

How can volume be measured

The volume of a cube or box can be measured by multiplying its length, width, and height (length x width x height).

The units of measure for volume are cubic units, such as cubic centimeters.

ANSWERED AT 01/04/2020 - 01:47 PM


QUESTION POSTED AT 01/04/2020 - 01:47 PM

If you combine 370.0 mL of water at 25.00 °C and 130.0 mL of water at 95.00 °C, what is the final temperature of the mixture? Use 1.00 g/mL as the density of water.

Even at STP, water can exist under 0 deg C. it quite is stated as sub-cooling. there is an significant concern in aviation stated as rime icing. Rime is a white or milky opaque granular deposit of ice. It occurs whilst supercooled water droplets strike an merchandise at temperatures at or under freezing.

ANSWERED AT 01/04/2020 - 01:45 PM


QUESTION POSTED AT 01/04/2020 - 01:45 PM

Using examples, how can you look at a substance and determine if it is a pure substance or a mixture?

A pure substance is something that is not mixed with anything like like a jar of rice or a jar of marbles
A mixture is something that is mixed together like if you made lemonade and you mixed lemon juice and water and sugar together it's a mixture and another example is if you mix sand and rocks together it's a mixture I hope I helped you

ANSWERED AT 01/04/2020 - 01:45 PM


QUESTION POSTED AT 01/04/2020 - 01:45 PM

What kind of bond is not formed by the differences in electronegativity

It's nonpolar covalent

ANSWERED AT 01/04/2020 - 01:45 PM


QUESTION POSTED AT 01/04/2020 - 01:45 PM

Work the following calculations: A) How many moles are in 23 grams of oxygen (Z=8)? B) What is the mass of 2.5 moles of nitrogen (Z=7)?

THE MASS OF 2.5 IS THE AMOUNT OF THE LINER EQUITATION SO DIVIDE 2.5 INTO 23 GRAMS AND MULTIPLY YOUR PROFIT BRO BTW IM NOT A COP SO STAY COOL MY FRIEND

ANSWERED AT 01/04/2020 - 01:44 PM


QUESTION POSTED AT 01/04/2020 - 01:44 PM

A change in which factor will affect the rate of reaction only when gases are involved?

I believe it is the pressure

ANSWERED AT 01/04/2020 - 01:44 PM


QUESTION POSTED AT 01/04/2020 - 01:44 PM

Which is not commonly mined metallic substance?

I think it is Mercury

ANSWERED AT 01/04/2020 - 01:43 PM


QUESTION POSTED AT 01/04/2020 - 01:43 PM

Comets orbit in short, circular paths around the sun. Is this true or false..? Thank you!

I think it's false because they travel in an elliptical pattern around the sun. There are some comets that travel in a 'v' shape.

ANSWERED AT 01/04/2020 - 01:40 PM


QUESTION POSTED AT 01/04/2020 - 01:40 PM

What is the mass, in grams, of 28.42 mL of acetone?

Answer:

22.48 grams.

Explanation:

In order to calculate this you just need to remember the formula for the density of materials, the density of Acetone is: 0.791 g/mL

So in order to calculte the mass we just use the next formula:

Density= mass/volume

Remember that mililiters is a unit for vulome:

Mass= Volume*density

We insert the values:

28.42*0.791ml=22.48 grams

So the mass og 28.42 mililiters of acetone will be 22.48 grams

ANSWERED AT 01/04/2020 - 01:37 PM


QUESTION POSTED AT 01/04/2020 - 01:37 PM

A roller coaster reaches its maximum potential energy when it A.is sitting at the top of a hill. B.reaches the bottom of a hill. C. rounds a curve. D. starts up a hill.


dont ask how
anyways 
abcdefghijklmnopqrstuvwxyz now I know my ABC whatever the rest of the lyrics are

ANSWERED AT 01/04/2020 - 01:30 PM


QUESTION POSTED AT 01/04/2020 - 01:30 PM

As the solar system formed, most of its mass became concentrated in one part of it. What is that that part?

That part of the solar system is the sun.  Of all the mass in
the total solar system, more than 99% of it is in the sun.

ANSWERED AT 01/04/2020 - 01:17 PM


QUESTION POSTED AT 01/04/2020 - 01:17 PM

The baseball team equipment manager received a shipment of new baseballs. Out 200 balls, 12% had defects. How many came without defects? Show work........

In order to solve, take the total and times the percentage: 

200 x 0.12 = 24 < 24 represents the number of baseballs that HAD defects.

To find which ones did not have defects, subtract 200-24, which is 176.

Answer: 176 

ANSWERED AT 01/04/2020 - 01:16 PM


QUESTION POSTED AT 01/04/2020 - 01:16 PM

Which of the following is an example of radiant energy? Lightning bolt Pot of water on a stove Television Sunlight

It should be sunlight . .

ANSWERED AT 01/04/2020 - 01:12 PM


QUESTION POSTED AT 01/04/2020 - 01:12 PM

What is the name of the compound ? Sn(CO3)2

The name of that is called Carbonate

ANSWERED AT 31/03/2020 - 10:48 AM


QUESTION POSTED AT 31/03/2020 - 10:48 AM

How many grams of Al2O3 are required to react completely with 1500.0 kJ of heat? 2Al2O3(s) + 3352 kJ → 4Al(s) + 3O2(g) answers 91.29 grams 2 grams 45.64 grams 1500 grams

Answer: 91.29 grams

Explanation:

2Al_2O_3(s)+3352kJ\rightarrow 4Al(s)+3O_2(g)

Endothermic reactions are those chemical reactions in which heat is absorbed by the reactants.

According to stoichiometry,

3352 kJ of energy is absorbed by  2 moles of Al_2O_3

Thus 1500 kJ of energy will be absorbed by=\frac{2}{3352}\times 1500=0.89moles of Al_2O_3

Mass of Al_2O_3=moles\times {\text {Molar mass}}=0.89\times 102g/mol=91.29g

ANSWERED AT 31/03/2020 - 10:44 AM


QUESTION POSTED AT 31/03/2020 - 10:44 AM

A large Ka means a strong acid? True or false

The answer is True :))

ANSWERED AT 31/03/2020 - 10:38 AM


QUESTION POSTED AT 31/03/2020 - 10:38 AM

Could element A and I ever bond to create a molecule? Why or why not?

A and I can be bond to create molecule

ANSWERED AT 31/03/2020 - 10:38 AM


QUESTION POSTED AT 31/03/2020 - 10:38 AM

Farah is doing an experiment that involves calculating the speed of a longitudinal wave. What will most likely happen if she increases the temperature in the room? a) The amplitude of the wave will increase. b) The amplitude of the wave will decrease. c) The speed of the wave will increase. d) The speed of the wave will decrease.

The correct answer is:

C. The speed of the wave will increase.

What will most likely happen if she increases the temperature in the room is the speed of the wave will increase.

|Huntrw6|

ANSWERED AT 29/03/2020 - 11:14 PM


QUESTION POSTED AT 29/03/2020 - 11:14 PM

Provide the nuclear equation for a decay of polonium-214

The nuclear equation that describes the alpha decay of Polonium-210 can be written like this:
210/
84Po→206/82Pb+4/2 He

ANSWERED AT 29/03/2020 - 06:33 PM


QUESTION POSTED AT 29/03/2020 - 06:33 PM

What can natural selection accomplish? prove Darwin's idea of "survival of the fittest" change relative number of inhabitants within a community favor a particular variety (color or size) of a species change one kind of organism into another in order to surviv

Natural selection makes it so that an organism from a species has a better chance of surviving than an organism in the same species, but with different traits. Survival of the fittest proves that certain traits can help an organisms survive better than its peers. For example, say there was an allele that made bears have thicker fur than others. The year-round climate is extremely cold. The bears with thicker fur are more likely to survive due to the warmth their fur provides and will have more offspring. The bears with thinner fur will die more often and not produce healthy offspring due to the frigid temperature. Eventually, the allele for thin fur will die out because the bears with these alleles cannot survive in their habitat.

ANSWERED AT 29/03/2020 - 06:30 PM


QUESTION POSTED AT 29/03/2020 - 06:30 PM

Which of the following atoms has the highest electronegativity? Use the periodic table to answer this question.

Fluorine is the most electronegative. So as the elements move further away, the less electronegative they are.. generally. So Nitrogen is less electronegative than Oxygen. And Bromine is less electronegative than Chlorine. As the periodic table moves towards the upper right corner towards Fluorine, the more electronegative the element.

ANSWERED AT 29/03/2020 - 06:28 PM


QUESTION POSTED AT 29/03/2020 - 06:28 PM

Electron Atom Actions I won't give a thanks if you tell me the answer tomorrow, I need it today thanks. Can someone check it and explain how you know if it's correct or not, I'm still confused on how to do this

I can tell that you got this right because it has to be a certain size and it is .
            great job!

ANSWERED AT 29/03/2020 - 06:24 PM


QUESTION POSTED AT 29/03/2020 - 06:24 PM

Hamid is viewing an image of a bird produced by a set of concave lenses. What must be true about the image? a) It is a virtual image. b)It is upside down. c)It is larger than the actual bird. d)It is capable of being projected.

The correct answer is option b, that is, it is upside down.  

A concave lens refers to a lens, which exhibits at least one surface that curves inwardly. It is a diverging lens, that is, it disperses out the rays of light, which have been refracted via it. A concave lens is thinner in the middle in comparison to its edges and is used in the correction of myopia.  

If the concave lens is used to observe the image of the bird, then the image will possibly be observed upside down.  


ANSWERED AT 29/03/2020 - 06:23 PM


QUESTION POSTED AT 29/03/2020 - 06:23 PM

Brock brings a magnet near a metal object. a magnetic force acts on an object, pulling it upward. which of the following best describes the magnetic force? a) frictional force b) contact force c) gravitational force d) a force that acts at a distance

Answer: Option (d) is the correct answer.

Explanation:

Magnetic force is the force which acts from one charged object to another charged or neutral object.

This force acts at a certain distance and if the charged objects are oppositely charged then they attract each other. When the charged objects have same charge then the objects repel each other.

Thus, we can conclude that a force that acts at a distance best describes the magnetic force.

ANSWERED AT 29/03/2020 - 06:22 PM


QUESTION POSTED AT 29/03/2020 - 06:22 PM

How can I do single replacement equations? For example, Silver metal immersed in potassium nitrate solution to yield. . .

Single replacement means only 1 will bond. Ag + KNO3 --> AgNO3 + K
Just a rough sketch

ANSWERED AT 29/03/2020 - 06:21 PM


QUESTION POSTED AT 29/03/2020 - 06:21 PM

Reducing the volume of a gas _____ its pressure if the temperature of the gas and the number of particles are constant.

Increases
I need to write more to post this so yea

ANSWERED AT 29/03/2020 - 06:17 PM


QUESTION POSTED AT 29/03/2020 - 06:17 PM