Answer:
18.2g/mol is the molar mass of the unknown solid assuming change in freezing point is 2.5°C
Explanation:
In this problem, there is no value of the freezing point depression and the constant for benzene, if:
Freezing point decreases by 2.5°C
And freezing point depression constant for benzene is 5.12°C/m
We can solve the problem as follows:
The freezing point depression is a colligative property that follows the equation:
ΔT = kf*m*ï
Where ΔT is change in temperature (We are assuming is 2.5°C)
Kf is freezing point depression constant for benzene (5.12°C/m)
m is molality of solution (Moles solute / kg solvent)
i is Van't hoff factor (For all solutes dissolved in organic solvents = 1)
Solving for m:
2.5°C = 5.12°C/m*m*1
m = 0.4883m
As molality is defined as moles of solute / kg of solvent and kg of solvent are 0.3632kg:
0.4883m = moles solute / 0.3632kg
0.177 moles of solute
Molar mass is defined as the mass of one mole of substance. Thus, molar mass of an unknown solid is:
3.232g / 0.177 moles of solute =
18.2g/mol is the molar mass of the unknown solid assuming change in freezing point is 2.5°C
6. According to the ideas of Democritus and Dalton, which of the following
statements is true about a piece of copper wire that s cut into the smallest
possible pieces? *
the copper will change properties and become a new element
the smallest piece of copper is no longer copper
the wire is still copper and does not change by cutting it
Answer: The wire is still copper and does not change by cutting it
Explanation:
Democritus postulated that all materials were composed of these tiny particles called as "atomos".
Daltons postulates are:.
1. All matter is made of very tiny particles called atoms.
2. Atoms is indivisible.
3. Atoms of a given element are identical in mass and chemical properties.
4. Atoms of different elements have different masses and chemical properties.
5. Atoms combine in the ratio of small whole numbers to form compounds.
6. The relative number and kinds of atoms are constant in a given compound.
Thus when copper wire is cut into the smallest possible pieces, the atoms were intact as they are indivisible and all atoms have same mass and chemical properties.Thus the wire is still copper and does not change by cutting it
How does electroplating happen?
A. A thin layer of metal is removed from a cathode.
B. Metal ions form a solid layer on a metal cathode.
C. Metal on a cathode forms ions in solution.
D. Metal ions in solution form a precipitate.
(Answer is B.)
Answer:
B
Explanation:
An electroplating happen when metal ions form a solid layer on a metal cathode. Therefore, option B is correct.
What is an electroplating ?The term electroplating is defined as the process of aligning another metal on the metal. Electroplating is usually used to change the physical properties of an object.
An electroplating is accomplished by an electroplating apparatus that contain a brine solution, a battery, wires, and alligator clips that kept carbon rods attached to the metal to be electroplated and the metal to be layered.
This process is used to give objects increased wear resistance, corrosion protection or aesthetic appeal and greater thickness. While electroplating is like advanced technology. It is primarily used to change the physical properties of an object.
Thus, option B is correct.
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This image shows the development of what climate phenomenon?
Answer:
Rain shadow
Explanation:
Climate is the average weather condition of a place over a long period of time.
The image shows a rain shadow effect around a mountainous region. The type of rainfall controlled this way is known as an orographic rainfall.
On the leeward side which is the opposite side of where the rain cloud forms, there is dryness and lack of rainfall. As moist air rises along the edge of the windward side, cloud forms. This windward side receives a significant amount of rainfall The windward side is hit with cold and dry wind and it is barren.To standardize a potassium permanganate solution, a 0.250 g sample of FAS (iron (II) ammonium sulfate hexahydrate; molar mass: 342 g) is dissolved in 25.00 mL distilled water, then acidified with sulfuric acid. The solution is then titrated with 35.00 mL potassium permanganate solution from a burette until a pale persistent purple color is attained. Calculate the molarity of the potassium permanganate solution.
Which of the following forces always exists between any two objects having mass?
Elastic force
Contact force
Gravitational force
Magnetic force
Answer:
C . Gravitational force
Explanation:
Answer:
Gravitational force
Explanation:
Gravitational force is commonly known as gravity or gravitation, which is a force that exists between all the objects present in this universe. For any two objects or particles having non-zero mass, a force of gravity exists between the which tends to attract them towards each other.
c. If the average basal rate of oxygen consumption for an adult is 15 L/hour, then calculate how many hours of oxygen use will you get from the 4.7 L tank?
Answer:
0.3hrs
Explanation:
Given parameters:
Average basal rate = 15L/hr
Volume of oxygen = 4.7L
Unknown:
Hours of oxygen use = ?
Solution:
Now to solve this rate problem, we need to find the time;
Hours of oxygen use = [tex]\frac{volume of oxygen }{average basal rate}[/tex]
Hours of oxygen use = [tex]\frac{4.7}{15}[/tex] = 0.3hrs
Daniella found an iron metal cube. The volume of the cube is 20 cm3 as shown below.
non
20.0 cm
If the density of iron is 7.9 g/cm3, what is the mass in grams of this iron cube?
A) 0.395 g
B) 2.53 g
C) 27.99
D) 158 g
Answer:b) 2.53
Explanation:
Select the correct term to complete each sentence.
1. If you ___________ the wavelength, the electromagnetic radiation energy will double.
2. The energy of the electromagnetic radiation will_____________ if you halve the wavenumber.
3. When the frequency of the light is doubled, its energy will___________.
a. halve
b. double
Answer: 1. halve
2. halve
3. double
Explanation:
The relationship between wavelength and energy of the wave follows the equation:
[tex]E=\frac{hc}{\lambda}[/tex]
E= energy
[tex]\lambda [/tex] = wavelength of the wave
h = Planck's constant
c = speed of light
Thus as wavelength and energy have inverse realation, when wavelength will halve , energy will double.
2. The between wavenumber and energy of the wave follows the equation:
[tex]E=h\times c\times \bar{\nu}[/tex]
E= energy
[tex]\bar{\nu}[/tex][tex]\nubar[/tex] = wavenumber of the wave
h = Planck's constant
c = speed of light
Thus as wavenumber and energy have direct relation, when wavenumber will halve , energy will be halved.
3. The relationship between energy and frequency of the wave follows the equation:
[tex]E=h\times \nu[/tex]
where
E = energy
h = Planck's constant
[tex]\nu[/tex] = frequency of the wave
Thus as frequency and energy have direct realation, when frequency will double , energy will double.
Which statement is FALSE?
A) Reproduction requires a lot of energy!
B) Some organisms choose not to reproduce because it uses too much energy.
C) Some organisms die after giving birth to their offspring. (Offspring means children).
D) Some organisms may fight to the death to mate with a female.
Someone who knows how to do this please help me!!!!!
Which of the following would increase as you move from the crust to the inner core? (There is only one right answer-- highlight it.) Temperature and pressure Water level and pressure Plant life and temperature Sunlight and temperature
Answer:
Temperature and pressure
Explanation:
As you go down within the earth from the crust to the core, the temperature and pressure levels increases significantly.
The deeper one goes within the earth, the hotter and more pressurized it becomes.
The reason for this is because of the increase in the overburden on the earth surface. As we move from a zone powered by the external heat engine, we launch into a phase dominated by internal processes. The internal processes are driven by the internal heat engine. The space here is confined and heat is not readily lost. Also, the overburden rock above increases the pressure as you go deeper.This process transforms_______ energy from the sun into chemical energy in the form of ______ which the plant can use to live and grow.
Answer:
uifhiuwrhuio fw
Explanation:
hfuiwehgu34iht3uht34[pht349348ut0tg
A 62.9 g sample of ground water is found to have a lead concentration of 13.97 ppm. Calculate the mass of lead in the sample in milligrams.
Answer:
0.879 mg
Explanation:
To solve this problem we need to use the definition of ppm:
ppm = μg solute / g solutionWith the above information in mind we can calculate the micrograms of lead using the concentration (13.97 ppm) and mass of solution (62.9 g):
μg lead = 13.97 ppm * 62.9 gμg lead = 878.713 μgFinally we convert μg to mg:
878.713 μg * [tex]\frac{1mg}{1000ug}[/tex] = 0.879 mg of leadEpsom salt can be used to season foods. How would you write its chemical
formula?
A. Na2CI B.NaCI
Answer:
B. NaCl
Explanation:
NaCl is sodium chloride, one form of it is epsom salt which we consume!
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Fill in the coefficients that will balance the following reaction: (Note: Use 1 as coefficient where appropriate.) NaCl + CaS → Na2S + CaCl2
Answer:
2NaCl + 1CaS → 1Na2S + 1CaCl2
Explanation:
The reaction in the question is a double-replacement reaction. The general formula is:
BX + CY → CX + BY
Where the cations of two salts exchange anions to produce 2 news products.
To balance the reaction:
NaCl + CaS → Na2S + CaCl2
We can balance as first the Na:
In reactants there is just 1 Na in NaCl but in products there are 2.
To balance Na:
2NaCl + CaS → Na2S + CaCl2
Now, there are 2 Na in reactants and products
There are 2 Cl in reactants and products
There is 1 Ca in both sides
And 1 S in both sides.
The balanced reaction is:
2NaCl + 1CaS → 1Na2S + 1CaCl2
Answer:
the answer is
2,1,1,1
Explanation:
Hope this helped!
H* ions increase in concentration at lower pH values.
Calculate how many more H" ions there are in a solution
at a pH =2 than in a solution at a pH =6. Find the
concentration of H* ions at a pH =2 and at a pH=6 in
Table B. Then divide the concentration of Ht ions at a
pH =2 by the of H* ions at a pH = 6. Record your answer
in Table C
the concentration of H* ions at a pH =2 = 10⁻²
the concentration of H* ions at a pH =6 = 10⁻⁶
a solution with a pH of 2 has 10⁴ times more hydrogen ions than a solution with a pH of 6
Further explanationThe concentration of H + ions in solution is measured in pH units. The greater the concentration of H + ions, the more acidic the solution will be, and vice versa if the concentration of H + ions is getting smaller, the more basic the solution and the greater the hydroxide concentration
The ph unit is on a scale between 0-14.
pH> 7, the solution is said to be alkaline
pH <7, the solution is said to be acidic
pH = 7, the solution is said to be neutral
Acidic solutions will have more hydrogen ions than hydroxide ions
A solution with a different value of n has a 10ⁿ difference in the concentration of H⁺ ions.
pH can be formulated:
[tex]\tt \boxed{\bold{pH=-log[H^+]}}[/tex]
the concentration of H* ions at a pH =2[tex]\tt 2=-log[H^+]\\\\(H^+]=10^{-2}[/tex]
the concentration of H* ions at a pH =6[tex]\tt 6=-log[H^+]\\\\(H^+]=10^{-6}[/tex]
pH 2 and pH 6
[tex]\tt \dfrac{10^{-2}}{10^{-6}}=10^4[/tex]
So a solution with a pH of 2 has 10⁴ times more hydrogen ions than a solution with a pH of 6
Calculate the fraction of acetic acid that is in the dissociated form in his solution. Express your answer as a percentage. You will probably find some useful data in the ALEKS Data resource. acetic acid
Answer:
0.11%
Explanation:
Without mincing words, let us dive straight into the solution to the question/problem. The first step to solve this question is to write out the chemical reaction, that is the reaction showing the dissociation of acetic acid.
CH3COOH <=======================================> CH3COO⁻ + H⁺
Initially, the amount present in the acetic acid which is = 12M, the concentration for CH3COO⁻ and H⁺ is 0 respectively.
At equilibrium, the amount present in the acetic acid which is = 12 - x, the concentration for CH3COO⁻ = x and H⁺ = x respectively. Note that the ka for acetic acid = 1.8 × 10⁻⁵.
1.8 × 10⁻⁵ = x²/ 14 - x. Therefore, x = 0.0158 M.
The next thing to do is to calculate for the percentage of dissociation, this can be done as given below:
percentage of dissociation = x/14 × 100. Recall that the value that we got for x = 0.0158 M. Hence, the percentage of dissociation = 0.0158 M/ 14m × 100 = 0.11%
How many valence electrons does a lithium (Li) atom have? The Periodic Table O A. 1 O B. 7 O C. 2 O D. 3
How many hydrogen atoms are in 1.50 x 10(22) molecules of water. Show your work.
A. 1.5 H atoms
B. 1.5 x 10(22) H atoms
C. 3 H atoms
D. 3 x 10(22) H atoms
Answer:
option B is a right answer
Explanation:
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What happens at the cathode in an electrolytic cell?
(Answer is reduction)
Answer:
At the cathode in an electrolytic cell, ions in the surrounding solution are reduced into atoms, which precipitate or plate out on to the solid cathode. The anode is where oxidation takes place, and the cathode is where reduction takes place.
Explanation:
Since positive ions pick up electrons at the negatively charged cathode, reduction takes place there.
What is reduction?The process of obtaining electrons or a decrease in an element's oxidation state in such a chemical reaction would be known as reduction, which is the movement of electrons among species. An increase in the number of electrons connected to a single or a collection of atoms is the result of a reduction chemical process.
What is electrons?The electron would be a subatomic particle with a negative one elementary charge electric charge. Due to their lack of components or substructure, electrons, which are part of the lepton particle family's first generation, have been typically regarded to be elementary particles.
In an electrolytic cell, the cathode is where ions in the neighboring medium could be converted into atoms, which then plate out or precipitated onto the solid cathode. Both oxidation and reduction occur at the anode but also cathode, respectively.
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How many muscle types is the muscular system made up of
Answer:
3
Explanation:
there are three types of muscles:
Skeletal(striated)SmoothCardiacplease helpp me i really need help
Answer:
second box is 2 C, third box is 3 C, and the last box is 3 C.
Explanation:
The permeability of packaging materials to CO2 is 6 times higher than the permeability to O2, which is 4 times higher than nitrogen. Despite its bigger molecular weight, carbon dioxide presents a much higher permeability, Why
Answer:
Due higher critical temperature, condensability and gas solubility.
Explanation:
The permeability of packaging materials to CO2 is 6 times higher than the permeability to O2 and nitrogen because carbondioxide gas has higher condensability and higher gas solubility in membranes. Due to its higher condensability and solubility, carbondioxide gas is more permeable that other gases such as oxygen and nitrogen gases. Carbondioxide gas also have higher critical temperature than other gases which make it more permeable than other gases.
Which of the following produces identical nuclei in cells? A pollination B miltosis C osmosis D fertilization
Answer:
Mitosis.
Explanation:
During mitosis, two nuclei must form, so that one nucleus can be in each of the new cells after the cell divides. In order to create two identical nuclei, the DNA inside of the nucleus must be copied or replicated.
what are the 5 steps to drawing a lewis structure??
Define wavelength and identify TWO points that could be used in the diagram to measure it.
During photosynthesis, water and carbon dioxide react to form oxygen and glucose.
True
False
Answer:
it's answer is true
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A reading before and after was taken from a burette, as shown.
What is the reading of the burette on the left, in mL? Do not type in units.
Im having a hard time reading the numbers on the left picture
Answer:
Reading on left looks like 1.4
Explanation:
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Which particles are in the nucleus of an atom? What are their charges?
Which particles orbit the outside of the atom? What is their charge?
Answer:
In the nucleus of an atom ,there are protons & neutrons. Protons have charge of 1.6× 10^-19 C, while neutrons have 0C charges. Electrons orbit outside the atom. Their charge is - 1.6 ×10^-19C
Explanation:
3
Solve and derive the unit for Power
Answer:
Unit of power is watt
Explanation:
Power = rate of doing work
or
Power, P = W/t
Where
W is work done and t is time
The unit of work done is Joules and that of time is seconds.
Power, P = J/s
We know that, J/s = watts
Hence, the unit of power is watts.