Answer:
c
Explanation:
Atoms of the same element can have different forms; for example, carbon-12 and carbon-14.
What causes the different forms?
What are these forms called?
What are the boiling points and freezing points (in oC)of a solution of 50.3 g of I2in 350 g of chloroform? The kb= 3.63 oC/m, the kf= 4.70 oC/m for CHCl3, and the molar mass of I2is 253.8 g/mol. The normal boiling point for CHCl3is 61.2 oC, and the normal freezing point for CHCl3is -63.5 oC.
Answer:
F.p ≈ - 66.16⁰c
B.p ≈ 59.1⁰c
Explanation:
Normal boiling point = 61.2⁰c
Normal freezing point = -63.5⁰c
Kb = 3.63⁰⁰ c/m
Kf = 4.70⁰ c/m
molar mass = 253.8 g/mol
solvent = 350 g = 0.35 kg
calculate The new freezing point and Boiling point
First we have to find the molality = number of moles / solvent in kg
= 0.198 / 0.35 = 0.5657 M
Hence the new freezing point can be calculated as
Normal freezing temp - new freezing temp = Kf * molality
= -63.5 - F.p = 4.7 * 0.5657
F.p = -63.5 - 2.6588 ≈ - 66.16⁰c
Boiling point
Normal boiling point - new boiling point = Kb * molality
= 61.2 - B.p = 3.63 * 0.5657
B.p = 61.2 - 2.0535 ≈ 59.1⁰c
The absolute temperature of a fixed mass of ideal gas is tripled while its volume remains constant. The ratio of the final pressure of the gas to its initial pressure is
Answer:
3 : 1
Explanation:
The following data were obtained from the question:
Initial temperature (T₁) = T
Initial pressure (P₁) = P
Final temperature (T₂) = 3T
Final pressure (P₂) =..?
Since the volume is constant, we shall use the following formula P₁ /T₁ = P₂ /T₂ to obtain the final pressure. This is illustrated below:
P₁ /T₁ = P₂ /T₂
P/T = P₂ /3T
Cross multiply
T × P₂ = P × 3T
Divide both side by T
P₂ = P × 3T /T
P₂ = P × 3
P₂ = 3P
Therefore, the final pressure is tripled.
Finally, we shall determine the ratio of the final pressure to the initial pressure as follow:
Initial pressure (P₁) = P
Final pressure (P₂) = 3P
Final pressure (P₂) : Initial pressure (P₁)
P₂ : P₁ => 3P/P
P₂ : P₁ => 3 : 1
Therefore, the ratio of the final pressure to the initial pressure is 3 : 1
Calculate the atomic mass of element "X" if it has 2 naturally occurring isotopes with the following masses and natural abundances. X−107 106.90509 amu 51.84%X−109 108.90476 amu 48.46%
Answer:
Using my (not very precise) periodic table, I get the mass of Ag as 107.87
Explanation:
This must be a combination of these two isotopes. So the % of the other isotope must be 48.16%.
To work with these percentages in an equation I'll use them as decimals.
So now I can start putting them into an equation:
107.87 = ( 106.905 ⋅ 0.5184 ) + ( x ⋅ 0.4816 )
Because both of the isotope masses, multiplied by their percentage, would give us the overall average mass.
107.87 = 55.419552 ⋅ ( x ⋅ 0.4816 )
Worked out the brackets that we can work out, and then rearrange to give:
107.87 − 55.419552 = ( x ⋅ 0.4816 )
Again rearrange:
52.450448 = ( x ⋅ 0.4816 )
And final rearranging:
x = 52.450448 - 0.4816
x
=
108.909
(using same sig figs as given in question)
You probably want to work through that again using your periodic table value for Ag.
3. The 2 in 1s2 represents the number of
located in that energy level.
Answers:
electrons
protons
Answer:
electrons
Explanation:
In an atom, you can have varying numbers of electrons, depending on if its an ion or not. You can use the orbitals to see the energy level of the atom.
An atom has only one number of protons. The number of protons cannot vary.
Lead (Pb) (average atomic mass 207.19 amu) has three naturally-occurring isotopes, Pb206, Pb207and Pb208 with isotopic masses of 205.98 amu, 206.98 amu and 207.98 amu respectively. If the isotopes Pb207and Pb208 are present in equal amounts, calculate the percent abundance of each isotope of Pb, which are, Pb206, Pb207 and Pb208.
Answer:
pb am 207.19 amu
pb206, pb207and pb208
A. The measured pH of a 0.100 M HCl solution at 25 degrees Celsius is 1.092. From this information, calculate the activity coefficient of H+.B. The measured pH of a solution of 0.010 HCl and 0.090 KCl at 25 degree Celsius is 2.102. Calculate the activity coefficient of H+ in this solution.C. Why does the pH change in part B relative to that in part A?
Answer:
activity coefficient [tex]\mathbf{\gamma =0.809}[/tex]
activity coefficient [tex]\mathbf{\gamma = 0.791}[/tex]
The change in pH in part A = 0.092
The change in pH in part B = 0.102
Explanation:
From the given information:
pH of HCl solution = 1.092
Activity of the pH solution [a] = [tex]10^{-1.092}[/tex]
[a] = 0.0809 M
Recall that [a] = [tex]\gamma[/tex] × C
where;
[tex]\gamma[/tex] = activity coefficient
C = concentration
Making the activity coefficient the subject of the formula, we have:
[tex]\gamma = \dfrac{[a]}{C}[/tex]
[tex]\gamma = \dfrac{0.0809 \ M}{0.100 \ M}[/tex]
[tex]\mathbf{\gamma =0.809}[/tex]
B.
The pH of a solution of HCl and KCl = 2.102
[a] = [tex]10^{-2.102}[/tex]
[a] = 0.00791 M
activity coefficient [tex]\gamma = \dfrac{0.00791 \ M}{0.01 \ M}[/tex]
[tex]\mathbf{\gamma = 0.791}[/tex]
C. The change in pH in part A = 1.091 - 1.0 = 0.092
The change in pH in part B = 2.102 -2.00 = 0.102
a race car at the Daytona 500 zips around the track .its travel the first 80 kilometers in 0.4 hours. the next 114 kilometers take 0.6 . the following 80 kilometers take 0.4 hours to calculate the race car average speed.
A race car at the Daytona 500 zips around the track its travel the first 80 km in 0.4 hours, the next 114km take 0.6, the following 80 km take 0.4, so the average speed is 195.71 km/hr.
How do we calculate the average speed?Average speed of any body will be calculated by dividing the total time to cover the ditance from the total distance covered.
Total distance to cover = 80km + 114km + 80km = 274km
Total time to cover distance = 0.4hr + 0.6hr + 0.4hr = 1.4hr
Average speed of car = 274/1.4 = 195.71 km/hr
So, the average speed of car is 195.71km/hr
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3-An analysis that determines the relative amounts of analytes in numerical terms
A) Quantitative Analysis
B) Qualitative Analysis
C)Quantitative Synthesis
D) Qualitative Synthesis
Q1-(30 Marks) Choose the correct answer
Answer:
A.
Explanation:
Quantitative analysis.
what's evaporation according to kinetic particle theory?
Answer:
Evaporation is a change of phase from liquid to gas explained as follows : When particles in the liquid phase are heated, they gain kinetic energy and move faster and further apart.
There are________
neutrons in the stable isotope of rhenium (Re-
185)
A.134
B.90
C.125
D.110
There are 110 neutrons in the stable isotope of rhenium. The correct option is D.
What are neutrons?A neutron is a subatomic particle that exists in the nucleus of all atoms except simple hydrogen. The name of the particle comes from the fact that it has no electrical charge; it is neutral. Neutrons have a very high density.
With the exception of the single-proton hydrogen nucleus, nuclei require neutrons to be stable. Neutrons are abundantly produced during nuclear fission and fusion.
Through mainly the process of fission, fusion, as well as neutron capture processes, they are a major contributor to the nucleosynthesis of chemical elements within stars.
The element rhenium-185 is made up of 75 protons, 110 neutrons, and 75 electrons. The element rhenium-187 is made up of 75 protons, 112 neutrons, and 75 electrons.
Thus, the correct option is D.
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(7.31 x 10+4 g) + (3.2300 x 10+3 g) =
Calculator answer
Final answer
What do metaloids share with nonmetals?
Answer:
Most metalloids have some physical properties of metals and some physical properties of nonmetals. They fall between metals and nonmetals in their ability to conduct heat and electricity. They are shiny like metals but brittle like nonmetals.
Explanation:
A scuba tank has pressure of 195 kpa at temperature 10 c the volume of the tank is 350 L how many grams of air ins in the tank?
Answer:
[tex]m=840.88g[/tex]
Explanation:
Hello,
In this case, considering the ideal gas equation as:
[tex]PV=nRT[/tex]
We can first compute the moles of air at the given conditions of 195 kPa (1.92 atm), 10 °C (283K) and 350 L:
[tex]n=\frac{PV}{RT}=\frac{1.92atm*350L}{0.082\frac{atm*L}{mol*K}*283K}\\ \\n=29.03molAir[/tex]
Next, since the molar mass of air is 28.97 g/mol, the mass is computed to be:
[tex]m=29.03mol*\frac{28.97g}{1mol} \\\\m=840.88g[/tex]
Best regards.
Which of the following is an example of a chemical change
A. apple slices turn brown
B. toast burns
C. silver tarnishes
D. all of these are chernical changes
Answer:
D. all of these are chemical changes
List the types of electromagnetic radiation in order of increasing frequency.
Answer:
In order of increasing frequency and decreasing wavelength these are: radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays and gamma rays........... ᕕ( ᐛ )ᕗ
..
Which statement best describes chemical properties of matter? Chemical properties, such as density, must be observed when a substance is in its natural state at room temperature and normal atmospheric pressure. Chemical properties, such as reactivity, must be observed when a substance is in its natural state at room temperature and normal atmospheric pressure. Chemical properties, such as combustibility, are generally observed as the identity of a substance changes and one or more new substances form. Chemical properties, such as boiling point, are generally observed as the identity of a substance changes and one or more new substances form.
Answer:
Chemical properties, such as combustibility, are generally observed as the identity of a substance changes and one or more new substances form.
Explanation:
Chemical properties, such as combustibility, are generally observed as the identity of a substance changes and one or more new substances form. Hence, option C is correct.
What are the chemical properties of matter?Chemical properties are properties that can be measured or observed only when matter undergoes a change to become an entirely different kind of matter.
Substances made of wood, such as paper and cardboard, are also flammable.
Chemical properties are properties that can be measured or observed only when matter undergoes a change to become an entirely different kind of matter.
They include reactivity, flammability, and the ability to rust.
Hence, option C is correct.
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Significant figure of 0.06300
Answer:
Number of Significant figures is : 4
Scientific Notation is: 6.3 x 10^-2
EXTRA HELP
Can someone please help with chemistry? Lead has a density of 10.5 g/cm^3. What is the diameter of a lead ball that has a mass of 500.0g? Report your answer in cm.
what is the volume occupied by 6.022 X 10*23molecules of any gas at STP.
Which is an example of pure chemistry? a. shape of a soybean plant b. chemicals containing carbon c. finding an antidote
The density of an element is 11.3 g/cm'. What is its density in kg/mº?
Answer:
11.3 g/cm³ = 11.3x100x100x100/ 1000 = 11300kg/m³
Explanation:
Identify the reagents
What are the components of the water-based carbon cycle?
Answer:
Carbon gets incorporated into marine organisms as organic matter or structural calcium carbonate.
Explanation:
ur welcome
Carbon gets incorporated into marine organisms as organic matter or structural calcium carbonate.
What is the carbon cycle?The carbon cycle describes how carbon moves between the atmosphere, soils, living creatures, the ocean, and human sources.
Carbon gets incorporated into marine organisms as organic matter or structural calcium carbonate. When organisms die, their dead cells, shells and other parts sink into deep water. Decay releases carbon dioxide into this deep water.
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which alkene represents the correct starting material phg?
Explanation:
The pH is larger than 7.
The relationship between pH and pOH is
pH + pOH = 14
if something is base, it's pH is greater than 7.
it's pOH is between 0 and 7.
How are the Celsius, Kelvin, and Fahrenheit scales similar? How are they different?
celcius and Fahrenheit are the same at -40 degrees since the scales converge . celcius and Kelvin become Equal at high temperatures as the difference. of 273. 15 between them gets lost in the noise . 0 degree Celsius is Equal to 32degrees Fahrenheit.
Give the name of each ion.
S2-
N3-
Answer:
The answer is Sulphur and Nitrogen ion
List all the different ways we can use a model to represent things
A 500 gram piece of metal had a volume of 2.75cm3. What is it’s density
Answer:
181.82 g/cm3
Explanation:
density is mass / volume so it is 500 / 2.75=181.82 g/cm3
The graph below shows the speed of a downhill
skier during a period of several seconds. Use the
graph to answer Question 13.
16
12
Speed (m/s)
8
0
1
3
3
2
Time (s)
13. Read Graphs What is the skier's acceleration?
Answer:
16
Explanation: