A 7.27-gram sample of a compound is dissolved in 250. grams of benzene. The freezing point of this solution is 1.02°C below that of pure benzene. What is the molar mass of this compound? (Note: Kf for benzene = 5.12°C/m.) Ignore significant figures for this problem. Group of answer choices 36.5 g/mol 146 g/mol 292 g/mol 5.79 g/mol 73.0 g/mol
Answer:
The correct answer is 146 g/mol
Explanation:
Freezing point depression is a colligative property related to the number of particles of solute dissolved in a solvent. It is given by:
ΔTf = Kf x m
Where ΔTf is the freezing point depression (in ºC), Kf is a constant for the solvent and m is the molality of solution. From the problem, we know the following data:
ΔTf = 1.02ºC
Kf = 5.12ºC/m
From this, we can calculate the molality:
m = ΔTf/Kf = 1.02ºC/(5.12ºC/m)= 0.199 m
The molality of a solution is defined as the moles of solute per kg of solvent. Thus, we can multiply the molality by the mass of solvent in kg (250 g= 0.25 kg) to obtain the moles of solute:
0.199 mol/kg benzene x 0.25 kg = 0.0498 moles solute
There are 0.0498 moles of solute dissolved in the solution. To calculate the molar mass of the solute, we divide the mass (7.27 g) into the moles:
molar mass = mass/mol = 7.27 g/(0.0498 mol) = 145.9 g/mol ≅ 146 g/mol
Therefore, the molar mass of the compound is 146 g/mol
A black object appears black because it reflects all light , and does not absorb any light. True or False
Answer:
False
Explanation:
It is the other way round, a black object appears black because it absorbs all the wavelength of light and does not reflect any light.
A black bucket will appear black because, it absorbs all wavelength of light incident on it. No other wavelength is reflected from the surface of the body. A black color suggests that a body is not reflecting any color. Instead such a body absorbing all the colors. For a white object, they reflect all the wavelength that is incident upon them.what’s the most abundant isotope of lawrencium
Answer:
266Lr
Thirteen isotopes of lawrencium are currently known; the most stable is 266Lr with a half-life of 11 hours, but the shorter-lived 260Lr (half-life 2.7 minutes) is most commonly used in chemistry because it can be produced on a larger scale.
Explanation:
hopefully that helps you
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Under the Law of Multiple Proportions, Carbon Dioxide has a ratio of 2.666 g
Oxygen for every 1 g Carbon. Given this, how much oxygen is present in a sample
of carbon dioxide that has 16 g of carbon?
Answer:
In carbon dioxide, on the right, there is 2.666 g of oxygen for every gram of carbon. So the ratio of oxygen in the two compounds is 1:2, a small whole number ratio
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18) A student determines the density of gold to be 20.9g/L. The true
density of gold is 19.30g/L. What is the student's percent error?round
answer to 2 significant figures *
Answer:
The answer is 8.29 %Explanation:
The percentage error of a certain measurement can be found by using the formula
[tex]P(\%) = \frac{error}{actual \: \: number} \times 100\% \\ [/tex]
From the question
actual density = 19.30g/L
error = 20.9 - 19.3 = 1.6
We have
[tex]p(\%) = \frac{1.6}{19.3} \times 100 \\ = 8.290155440...[/tex]
We have the final answer as
8.29 %Hope this helps you
Solid calcium chlorate decomposes to form solid calcium chloride and oxygen gas.
Write the balanced chemical equation for the reaction described. Phases are optional.
equation:
Answer:
Ca(ClO₃)₂(s) → CaCl₂(s) + 3O₂(g)
Explanation:
Chemical equation:
Ca(ClO₃)₂(s) → CaCl₂(s) + O₂(g)
Balance chemical equation:
Ca(ClO₃)₂(s) → CaCl₂(s) + 3O₂(g)
Step 1:
Ca(ClO₃)₂(s) → CaCl₂(s) + O₂(g)
Left hand side Right hand side
Ca = 1 Ca = 1
Cl = 2 Cl = 2
O = 6 O = 2
Step 2:
Ca(ClO₃)₂(s) → CaCl₂(s) + 3O₂(g)
Left hand side Right hand side
Ca = 1 Ca = 1
Cl = 2 Cl = 2
O = 6 O = 6
On average, about ____________ of incoming solar radiation is reflected back to space.
A 50%
B 30%
C 20%
D 10%
6. Clownfish, sea anemone, coral, sea urchins, sponges and parrot fish are 5 points
just a few examples of the large variety of organisms that can be found in
a coral reef. The coral reef and its inhabitants (residents) are suffering due
to several factors such as pollution, coastal development, sedimentation
and destructive fishing practices. What would be the most likely result if
some of the species in the coral reef are destroyed? *
Answer:
The orange-and-white clownfish you know from Hollywood is only one of 30 species of clownfish that live in coral reefs around the world; small in size and big in personality, these tiny comedians have one of the most unique lifestyles in the reef. The orange-and-white clownfish you know from Hollywood is only one of 30 species of clownfish that live in coral reefs around the world; small in size and big in personality, these tiny comedians have one of the most unique lifestyles in the reef.
Explanation:
point being, it would be absolutely terrible
Coral reef are the biggest biodiversity in the world. Therefore, destruction of coral reefs definitely affect the aquatic livings. As well as it leads to erosion of seashore lines.
What are coral reefs?Corals reefs are the habitat of 25% of sea organisms. It means there are well over a million species that rely on coral reefs for their existence. The reef offers these organisms the vital food, habitat, and breeding grounds required for the survival of their species.
The marine biodiversity would suffer greatly if their homes vanished. And many fish, turtles, and other species would vanish in a domino-like fashion.
Coral reefs are threatened by a number of things, such as local threats like overfishing, destructive fishing methods, coastal development, pollution, and careless tourism, as well as global effects of climate change like warming seas and rising CO₂ levels in the water. Natural phenomena like hurricanes, El Nio, and diseases are also a threat to oral reefs.
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PLSSS HELP Match each image to the
correct step of meiosis. PLS HELP
Answer:
Explanation:
Here you go!! Hope this helps.
In chemistry, one often uses a unit of charge known as the Faraday, F, which has the magnitude of the charge of 1 mole of electrons. How many faradays of charge does that correspond to
Answer:
1 Faraday
Explanation:
This question seeks to test proper understanding of Faraday's second law of electrolysis which states when the same quantity electricity passes through a solution of different electrolytes, the mass of the substance deposited is directly proportional to there chemical equivalence.
This law hints at the charges of ions being the chemical equivalence and also been represented as the unit for the quantity of electricity in faraday, F. Hence, a metal with the charge of 1+ can be displaced by 1F (which is equal to 96, 500 coloumbs). This charge also represents one molecule of electron, thus 1 faraday corresponds to one mole of electrons.
NOTE: It should be noted that a metal with the charge of 2+ can be displaced by 2F and so on.
Which number represetns a coefficient?
2
3
4
7
(5x10^3) + (4.3x10^4)=
Answer:
48000
Explanation:
maths
Answer:
48000
Explanation:
(5x10^3) = 5 × 1000 = 5000
(4.3x10^4) = 4.3 × 10000 = 43000
5000 + 43000 = 48000
What is the frequency of a wave having 4.90 x 10 -12 J of energy?
Answer:
The answer is
[tex] \huge 7.40 \times {10}^{21} Hz[/tex]
Explanation:
To find the frequency of the wave we use the formula
[tex]f = \frac{E}{h} \\ [/tex]
where
E is the energy
f is the frequency
h is the Planck's constant which is
6.626 × 10-³⁴ Js
From the question
E = 4.90 × 10-¹² J
So we have
[tex]f = \frac{4.90 \times {10}^{ - 12} }{6.626 \times {10}^{ - 34} } \\ [/tex]
We have the final answer as
[tex]7.40 \times {10}^{21} \: \: Hz[/tex]
Hope this helps you
In which atmospheric layer is the ozone layer?
A.troposphere
B.mesosphere
C.stratosphere
D.thermosphere
Answer:
stratosphere
Explanation:
contains a high concentration of ozone in relation to other parts of the atmosphere, although still small in relation to other gases in the stratosphere.
Answer:
stratosphere
Explanation: Most atmospheric ozone is concentrated in a layer in the stratosphere, about 9 to 18 miles (15 to 30 km) above the Earth's surface. Ozone is a molecule that contains three oxygen atoms.
Which is an example of a current research focus in chemistry?
A. applying gene therapy to treat certain diseases
B. using hook-and-loop tape in the clothing industry
C. developing smoke detectors for common use
D. studying coal combustion as an energy source
Answer:
b is the correct answer
do not trust answer one
Explanation:
In which Earth system does the rock cycle take place?
cryosphere
atmosphere
geosphere
biosphere
Answer:
geosphere
Explanation:
geo means rocks this is the area
hope this helps dude
Atomic radius is....
O The tendency for an atom to attract electrons
The energy required to remove an electron
O The energy required to add an electron
O The distance from the nucleus to the last orbital
A tree frog uses plants or trees for protection from the rain. The frog is protected from the rain and the tree is neither helped nor harmed
What type of energy is defined as the kinetic energy of the atoms of a substance?
Explanation:Thermal energy, or heat, is the energy that comes from the movement of atoms and molecules in a substance. Heat increases when these particles move faster. Geothermal energy is the thermal energy in the earth. Motion energy is energy stored in the movement of objects.
I hope this helped!
Discuss the relationship between atoms, elements and compounds. Include in your discussion if these are mixtures or pure substances and why.
Answer:
Elements are the simplest complete chemical substances. Each element corresponds to a single entry on the periodic table. An element is a material that consists of a single type of atom. Each atom type contains the same number of protons.
Chemical bonds link elements together to form more complex molecules called compounds. A compound consists of two or more types of elements held together by covalent or ionic bonds.
Explanation:
The pOH of an aqueous solution of 0.480 M trimethylamine (a weak base with the formula (CH3)3N) is .
Answer:
Explanation:
Kb of (CH₃)₃N is 7.4 x 10⁻⁵
initial concentration of (CH₃)₃N a is .48 M
(CH₃)₃N + H₂O = (CH₃)₃NH⁺ + OH⁻
a - x x x
x² / (a - x ) = Kb
x is far less than a so a - x can be replaced by a .
x² / a = Kb
x² = a x Kb = .48 x 7.4 x 10⁻⁵ = 3.55 x 10⁻⁵ = 35.5 x 10⁻⁶
x = 5.96 x 10⁻³
pOH = - log ( 5.96 x 10⁻³ )
= 3 - log 5.96
= 3 - .775
= 2.225
Level 1 01 Which correctly pairs the outside particles with their charge? A. Electrons: Positive B. Protons: Positive C. Neutrons: Neutral D. Electrons: Negative
Answer:
D. Electrons: Negative.
Explanation:
Hello, happy to help you today!
In this case, by considering the Bohr's atomic model in which atom is composed by a nuclei containing both protons and neutrons which are positively and neutrally charged respectively and surrounding electrons assembled in orbits or levels of energy which are negatively charged in order to provide a balance to the atom, the correct statement is: D. Electrons: Negative. Also consider the Bohr's model on the attached picture.
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Phosphoric acid, which is commonly used as rust inhibitor, food additive and etching agent for dental and orthopedic use, can be synthesized using a two-step thermal process. In the first step, phosphorus and oxygen react to form diphosphorus pentoxide: P4(l)+5O2(g-2 P20s(g) In the second step, diphosphorus pentoxide and water react to form phosphoric acld P20(9)+3 H200 2H,PO40) Write the net chemical equation for the production of phosphoric acid from phosphorus, oxygen and water.
Answer:
P₄(l) + 5 O₂(g) + 6 H₂O(l) ⇒ 4 H₃PO₄(aq)
Explanation:
Phosphoric acid is synthesized using a two-step thermal process.
In the first step, phosphorus and oxygen react to form diphosphorus pentoxide. The corresponding chemical equation is:
P₄(l) + 5 O₂(g) ⇒ 2 P₂O₅(g)
In the second step, diphosphorus pentoxide and water react to form phosphoric acid. The corresponding chemical equation is:
P₂O₅(g) + 3 H₂O(l) ⇒ 2 H₃PO₄(aq)
We can get the net chemical equation by adding the first step, the second step multiplied by 2, and canceling what is repeated on both sides.
P₄(l) + 5 O₂(g) + 2 P₂O₅(g) + 6 H₂O(l) ⇒ 2 P₂O₅(g) + 4 H₃PO₄(aq)
P₄(l) + 5 O₂(g) + 6 H₂O(l) ⇒ 4 H₃PO₄(aq)
Is lead a representative metal or transitional metal?
Answer:
It's a representative metal
Explanation: Transitional metals are metals of various chemical elements and have valence electrons—i.e., electrons that can participate in the formation of chemical bonds.
how can you tell where sugar enters the blood stream
please help asap
Answer:
Sugar can't enter cells directly , so when blood sugar level rises, ... signal for the release of insulin into the bloodstream.
Explanation:
yes when the sugar enter the bloodstream it may slowly slowly effect in your body and it may causes diabetes
how many moles are in a 4.2 gram gold sample
Ten moles of hydrogen are allowed to react with 6 moles of oxygen. How much water will be
obtained from reaction on complete consumption of one gas?
Answer:
10 moles of water are produced,
Explanation:
Given data:
Moles of H = 10 mol
Moles of O = 6 mol
Water obtained = ?
Solution:
Balance chemical equation:
2H₂ + O₂ → 2H₂O
Now we will compare the moles of H₂ and O₂ with water from balance chemical equation.
H₂ : H₂O
2 : 2
10 : 10
O₂ : H₂O
1 : 2
6 : 2×6 = 12
Number of moles of water produced by hydrogen are less so hydrogen will be limiting reactant and it will limit the yield of water thus, 10 moles of water are produced.
Use the drop-down menu to complete the statement.
Atoms of elements in the same group have the same number of
. This is why they have similar chemical properties.
Answer:
valence electrons
Explanation:
other guy was close enough
Atoms of elements in the same group have the equal number of valence electrons. That is why they have similar chemical properties.
Why does the element in the same group have similar chemical behavior?The chemical properties of elements depend on the number of valence electrons in their outermost shell. Those elements which are placed in the same group in the periodic table have the same number of valence electrons.
Therefore, elements present in the same group of the modern periodic table have similar chemical behavior.
The elements having a similar valence shell electronic configuration in their atoms are arranged in the same group of the periodic table. These valence electrons decide the chemical properties and reactivities of the chemical elements.
For example, all the elements in group 1 of the periodic table have one electron in their valence shell and all the elements present in group 17 have seven electrons in their valence shell.
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When 435 J of heat is added to 3.4 g of olive oil that's at 21 Deg C, it's
temperature increases to 85 Deg C. Calculate the specific heat of Olive oil? Show work
Answer:
k Nishant
Explanation:
i don't know sorry but u can search in google
Explain how plucking occurs
Answer:
plucking is usually extracting hair
Explanation:
example: pluck the chicken feathers
pluck my brows