Answer:
THE NORMAL BOILING POINT OF A SOLUTION CONTAINING 64.5 g OF QUINOLINE IN 500 g OF BENZENE IS 82.6 C
Explanation:
Boiling point = old boiling point + molarity * boiling point constant (Kb)
First, you calculate the number of moles of quinoline in the solution
number of moles = mass / molar mass
Since the molar mass of quinoline has been given as 129 g/mol
number of moles = 64.5 g / 129 g/mol
number of moles = 0.5 moles.
Next is to determine the molarity:
molarity = number of moles of solute / kilogram of solvent
molarity = 0.5 moles / 500/1000 kg
molarity = 0.5 / 0.5
molarity = 1 M
The new boiling point can then be calculated using the formula:
B. P = old B.P + Kb * molarity
B.P = 80.10 + 2.50 * 1
B.P = 80.10 + 2.50
B.P = 82.6 degree celsius
Geetha took some grains of boiled rice in test tube A and Tina took boiled and chewed rice in test tube B. Both of then poured 1-2 drops of iodine solution into the test tubes. What would they have observed? Give a reason for your answer.
Answer:
Test tubes A and B turn a darker blue color.
Explanation:
Based on the information provided in the question it can be said that they should have noticed that Tube A and Tube B turned a dark blue color. This is because the starch turns the solution in the test tubes into a dark blue color due to the negative reaction caused by the conversion of starch present in salivary amylase
plsss answer this?? i need help
Answer:
85.34 g of oxygen
Explanation:
Carbon and Oxygen combine in ratio 3:8 to form CO2
Weight of C = 32g
3g of carbon reacts with 8g of oxygen
1g of carbon reacts with 8/3 g of oxygen
32 g of carbon reacts with 8/3 (32)
= 256/3
= 85.34 g of Oxygen
Hope it helps....
The sodium salt, NaA, of a weak acid is dissolved in water; no other substance is added. Which of these statements (to a close approximation) is true?
Answer:
Your question is somewhat poorly worded, even so what I can contribute is the statement is false, since the salt is sodium chloride, where its severe chemical formula NaCl, is a SALT not an acid and if it dissolves in water, seriously the solute of a solution, where water plays the role of the solvent
Explanation:
Sodium chloride is a binary salt, very easy to dissolve in water, it is also called the famous table salt, since it can be ingested in food even though it is not so recommended against high blood pressure conditions.
which substance will form a solution when mixed with liquid benzene (c6h6)
Answer: [tex]I_{2} (l)[/tex]
Explanation: Because C 6 H 6 is nonpolar substance and I 2 is also nonpolar compound
According to the concept of solubility,iodine will form a solution when mixed with liquid benzene as both are non-polar substances.
What is solubility?Solubility is defined as the ability of a substance which is basically solute to form a solution with another substance. There is an extent to which a substance is soluble in a particular solvent. This is generally measured as the concentration of a solute present in a saturated solution.
The solubility mainly depends on the composition of solute and solvent ,its pH and presence of other dissolved substance. It is also dependent on temperature and pressure which is maintained.Concept of solubility is not valid for chemical reactions which are irreversible. The dependency of solubility on various factors is due to interactions between the particles, molecule or ions.
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Identify this molecule
Answer:
Ribose
Explanation:
This is the pentose sugar found in RNA commonly.
How much cesium (half-life = 2 years) would remain from a 10 g sample after
4 years?
O A. Og
OB. 8g
O c. 59
O D. 29
SUBMIT
Answer: 2.5 grams
Explanation:
Expression for rate law for first order kinetics is given by:
[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]
where,
k = rate constant
t = age of sample
a = let initial amount of the reactant
a - x = amount left after decay process
a) to calculate the rate constant:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
[tex]t_{\frac{1}{2}}=\frac{0.693}{k}[/tex]
[tex]k=\frac{0.693}{2years}=0.346years^{-1}[/tex]
b) to find amount left after 4 years
[tex]4=\frac{2.303}{0.346}\log\frac{10}{a-x}[/tex]
[tex](a-x)=2.5g[/tex]
Thus 2.5 g of cesium would remain from a 10 g sample after 4 years
what is electrolysis
Answer:
electrolysis is a technique that uses a direct electric current to drive an otherwise non-spontaneous chemical reaction
Explanation:
S
Perform the following operation
and express the answer in
scientific notation.
1.248x10-2 : 7.8x10-7
[? ]x10
Answer: [tex]1.6\times 10^4[/tex]
Explanation:
Scientific notation is defined as the representation of expressing the numbers that are too big or too small and are represented in the decimal form with one digit before the decimal point times 10 raise to the power.
For example : 5000 is written as [tex]5.0\times 10^3[/tex]
In division , the result would contain the same number of significant digits as there in the least precise number , thus the answer would have 2 significant digits.
[tex]\frac{1.248\times 10^{-2}}{7.8\times 10^{-7}}=1.6\times 10^4[/tex]
Which of the following is true about the principle of the conservation of mass? *
1 point
d. The mass of the products is never equal to the mass of the reactants.
e. The mass of the products is less than the mass of the reactants.
f. The mass of the products is equal to the mass of the reactants.
g. The mass of the products is greater than the mass of the reactants.
Answer:
F
Explanation:
"The mass of the products is equal to the mass of the reactants" is true about the principle of the conservation of mass.
So, option f is correct one.
What is the principle of conservation of mass?The principle of the conservation of mass states that mass can neither be created nor be destroyed in a chemical reaction, it only transferred from reactants to products. It means that mass of reactants is equal to mass of products.Example when wood burns the mass of shoot, ashes, and gases equal to the original mass of of charcoal and oxygen when it first react.To learn more about conservation of mass here.
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The octane number of fuel is 79%. What does that mean
Answer:
Octane number, measure of the ability of a fuel to resist knocking when ignited in a mixture with air in the cylinder of an internal-combustion engine.
Octane number is also known as octane rating. Octane numbers are based on a scale on which isooctane is 100 (minimal knock) and heptane is 0 (bad knock). The higher the octane number, the more compression required for fuel ignition. Fuels with high octane numbers are used in high performance gasoline engines.
(Hope this helps) Sky
An invasive fish species was accidentally introduced into a river. At first, it experienced a sudden surge in its population. Then it experienced a steady decline. Which statements give plausible reasons for this trend?
Answer:
Correct Option is Option A
A.)It became prey to certain organisms in the river.
Explanation:
CHECK COMPLETE QUESTION BELOW;
An invasive fish species was accidentally introduced into a river. At first, it experienced a sudden surge in its population. Then it experienced a steady decline. Which statements give plausible reasons for this trend?
A.It became prey to certain organisms in the river.
B.It lacked adaptations suitable for that particular ecosystem.
C.It had no predators in its new environment.
D.It had few organisms to compete with for resources.
Aquatic invasive species are species such as fish or invertebrate that is absorbed by new aquatic environment that are differ from their own natural environment.
When Aquatic invasive species found themselves in a new environment, at first they will experience a rapid increase in the number of their population this is because of the lack of natural predators in the new aquatic environment. As a result of this they bring about the alteration of food web structure, they take in charge of available food for the native species and compete with them. As a result of this competition involved there is a decrease in the population.
Therefore, the statements that gives plausible reasons for this trend is that became prey to certain organisms in the river.
Answer:
It became prey to certain organisms in the river.
It lacked adaptations suitable for that particular ecosystem.
Explanation:
Took the test on Edmentum
In which orbitals would the valence electrons for carbon (C) be placed?
Answer: orbitals supernumerary
Explanation:
Answer:
both S orbital and p orbitals
Explanation:
took the exam got the question right.
what is chemistry?
Answer:the branch of science which examines the material of the universe and changes that these materials undergo
Chemistry deals with composition,structure,properties of matter and changes that these materials undergo
polarity of the molecules increase with electro nogativity
Answer:
true
Explanation:
polarity of the molecules increased with electronegatiy it's true
What is the total energy change for the following reaction: H2 + I2 -> 2HI?
Given:
H-H bond: 436 kJ/mol
I-I bond: 151 kJ/mol
H-I bond: 297 kJ/mol
A. +7 kJ/mol
B. +297 kJ/mol
C. -290 kJ/mol
D. -7 kJ/mol
Energy change is the conversion of the energy stored in reactants to products. In the reaction between hydrogen and iodine, the energy change is -7 kJ/mol. Thus, option D is correct.
What is total energy change?Total energy change is the conversion of the energy from a substance to another when the reactant undergoes modification to produce a product.
The reaction is given as,
H₂ + I₂ → 2HI
In the reaction, the bonds between H-H and I-I are broken to release energy that produces two H-I bonds as the product.
Given,
H-H bond = 436 kJ/mol
I-I bond = 151 kJ/mol
H-I bond = 297 kJ/mol
So, 436 kJ/mol + 151 kJ/mol - 2x297 kJ/mol = -7 kJ/mol
Therefore, -7 kJ/mol is the total energy change in the reaction involving hydrogen and iodine.
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I need this fast plz, 50 points
By doing which action will you decrease the number of collisions and energy of reactant molecules?
A.) decreasing the temperature of the reactant mixture
B.) increasing the pressure of the reactant mixture
C.) decreasing the concentration of reactants
D.) adding a catalyst
Answer:
It is decreasing the temperature of the reactant mixture.
Explanation:
Just took the test
In order to decrease the number of collisions and energy of reactant molecules, the temperature of the reactant mixture would need to be decreased as well.
Temperature of reactantsThe temperature of reactants is proportional to the average kinetic energy of the molecules of the reactants.
Also, the higher the average kinetic energy of the reactant molecules, the higher their chances of colliding and reacting to form products.
Thus, in order to decrease their energy and collision frequency, the temperature of the reactant mixture needs to be decreased.
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Which factor affects gravitational potential energy but not elastic potential energy?
Answer:
spring constant. acceleration due to gravity. distance from a given position. amount of matter in the object.
Explanation:
hope this helps you :)
Answer:
spring constant
Explanation:
Give some examples of how ultraviolet rays can be used
Answer:
One of the most common ways of producing UV light is passing an electric current through vaporized mercury or some other gas. This type of lamp is commonly used in tanning booths and for disinfecting surfaces. The lamps are also used in black lights that cause fluorescent paints and dyes to glow.Explanation:
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Which describes two phases in dynamic equilibrium?
O A. Molecules in one phase continually change to the other.
O B. The total number of molecules must be equal in each phase.
O C. Molecules do not change from one phase to the other.
O D. The total number of molecules in each phase stays constant.
Answer:
The total number of molecules in each phase stays constant
Explanation:
i just took the test and got it right.
In the dynamic equilibrium between 2 phases, the total number of molecules in each phase stays constant (Option D).
When does dynamic equilibrium occur?Dynamic equilibrium occurs when the direct and reverse rates are equal and the concentrations remain constant over time.
Which describes two phases in dynamic equilibrium?
A. Molecules in one phase continually change to the other. NO. Molecules in both phases continually change.B. The total number of molecules must be equal in each phase. NO. This is not necessarily true.C. Molecules do not change from one phase to the other. NO. This would be a static equilibrium.D. The total number of molecules in each phase stays constant. YES. Since the forward and reverse rates are equal.In the dynamic equilibrium between 2 phases, the total number of molecules in each phase stays constant (Option D).
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How many atoms or molecules are in 5.0 moles of the following?
a. O
b. N
c.MgCl₂
d. C₂H₃NO
Answer:
They all have the same number of molecules or atoms which is 3.011*10²⁴ molecules or atoms.
5 moles of O = 3.011*10²⁴ molecules or atoms
5 moles of N = 3.011*10²⁴ molecules or atoms
5 moles of MgCl2 = 3.011*10²⁴ molecules or atoms
5 moles of C2H3NO = 3.011*10²⁴ molecules or atoms.
Explanation:
a)
5 moles of O = ?
1 mole of any substance is equal to Avogadro's number which is equal to 6.022×10²³molecules or atoms
From the question above,
5 moles of O = 5 × 6.022*10²³ = 3.011×10²⁴atoms or molecules.
b)
5 moles of N
From the same principle or fundamentally stated fact above,
1 mole of any substance = 6.022*10²³molecules or atom
5 moles of N = 5 × 6.024
2*10²³ = 3.011*10²⁴atoms or molecules.
c)
5 moles of MgCl₂
Same principle we used in a and b,
1 mole of any substance = 6.022*10²³ atoms or molecules
5 moles of MgCl2 = 5.0×6.022*10²³ = 3.011*10²⁴ atoms or molecules.
d)
5 moles of C₂H₃NO = ?
1 mole of C₂H₃NO = 6.022*10²³molecules or atoms
5 moles = x molecules or atoms
x = 5 × 6.024
2*10²³ = 3.011*10²⁴ atoms or molecules
What this proves is that no matter the compound, molecule or element, as long as they have equal amount of moles, they'll have the same number of atoms, molecules or particles.
Answer:
a. 3.011x10²⁴ atoms of O in 5 moles.
b. 3.011x10²⁴ atoms of N in 5 moles.
c. 3.011x10²⁴ atoms of MgCl₂ in 5 moles.
d. 3.011x10²⁴ atoms of C₂H₃NO in 5 moles
Explanation:
A mole is defined as the number of atoms in exactly 12.000g of ¹²C.
This number is equal to 6.022x10²³. That means 1 mole is equal to 6.022x10²³.
Thus:
a. O . 5 moles of oxygen (An atom) are:
5 moles O ₓ (6.022x10²³ atoms of O / mole) = 3.011x10²⁴ atoms of O in 5 moles
b. N . Also, 5 moles of nitrogen are:
5 moles N ₓ (6.022x10²³ atoms of N / mole) = 3.011x10²⁴ atoms of N in 5 moles
c. MgCl₂ . Magnesium chloride is a molecule. Again, 1 mole of MgCl₂ contains 6.022x10²³ molecules and 5 moles are:
5 moles MgCl₂ ₓ (6.022x10²³ molecules of MgCl₂ / mole) = 3.011x10²⁴ atoms of MgCl₂ in 5 moles
d. C₂H₃NO. 5 moles of C₂H₃NO are:
5 moles C₂H₃NO ₓ (6.022x10²³ molecules of C₂H₃NO / mole) = 3.011x10²⁴ atoms of C₂H₃NO in 5 moles
As you can see, number of molecules of 1 mole doesn't depend on the nature of the substance.
Acetylene is the simplest hydrocarbon
that contains carbon-carbon triple bond.
Hydrocarbons are the compounds of
carbon and hydrogen.
identify the branch of Chemistry??
Answer:
organic chemistry
because it is study of carbon containing substances
Organic chemistry is the branch of Chemistry where hydrocarbons are the compounds of carbon and hydrogen.
What is organic chemistry?Organic chemistry is the study of the structure, properties, composition, reactions, and preparation of carbon-containing compounds.
Hydrocarbons Derivatives are compounds which are made up of hydrogen and carbon with specific functional groups attached to them.
Examples:- Aldehydes, ketones, carboxylic acids, alcohols, alkyl halides, ethers, amines etc.
Hence, organic chemistry is the branch of Chemistry where
hydrocarbons are the compounds of carbon and hydrogen.
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Which structure below contains all of the others?
DNA
gene
chromosome
nucleus
Answer:
nucleus
Explanation:
The nucleus holds all the other things, keeping them safe and confined.
Answer:
Nucleus
Explanation:
It contains DNA which contains a GENE which contains a CHROMOSOME so its NUCLEUS
-pls help will mark brainliest-
Answer:
Explanation: d
Give four differences between rusting and burning
Answer:
burning is a rapid process, rustig is a slow process. burning releases light during the process,rusting does not. burning can speed up with addition of more external conditions, rusting cannot be sped up greately by addition of external materials. burning results in release of large amts of heat, rusting very little amt of heat
Hope helped
plesse give a thank
and most brainlest
-Rust happens when something is unpolished and is old. Burning has been modified by heat.
-Burning is a chemical change. Rust is a physical change.
-Burning something cannot be fixed back to its natural form, while when something is rusted it can possibly be re-used and fixed.
-The texture of something burnt is usually fragile and brittle while rust makes (metal for example) gritty.
-Rust usually forms solely on metals while almost anything can be burned.
note: you asked for 4 answers but i gave you 5 in case you didnt like any of them. Hope this helps!
evidence of a chemical change includes?
Answer:
Change of color, change in temperature, change of energy or loss heat, odor etc....
How many grams of chlorine gas are needed to react with 3.5 liters of a 1.7 molar
potassium bromide solution?
Cl2 + 2 KBr - 2 KCl + Br2
Answer: 211.2 grams
Explanation:
To calculate the number of moles for given molarity, we use the equation:
[tex]\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution in L)}}[/tex] .....(1)
Molarity of [tex]KBr[/tex] solution = 1.7 M
Volume of solution = 3.5 L
Putting values in equation 1, we get:
[tex]1.7M=\frac{\text{Moles of}KBr}{3.5L}\\\\\text{Moles of }KBr=\{1.7mol/L\times 3.5L}=5.95moles[/tex]
The balanced chemical reaction is:
[tex]Cl_2+2KBr\rightarrow 2KCl+Br_2[/tex]
According to stoichiometry:
2 mole of KBr requires = 1 mole of [tex]Cl_2[/tex]
5.95 moles of KBr requires = [tex]\frac{1}{2}\times 5.95=2.975[/tex] moles of [tex]Cl_2[/tex]
Mass of [tex]Cl_2=moles\times {\text {Molar mass}}=2.975mol\times 71g/mol=211.2g[/tex]
Thus 211.2 grams of chlorine gas are needed to react with 3.5 liters of a 1.7 molar potassium bromide solution
In the following reaction, which are the products?
Mg + 2HCl —> H2 + MgCl2
If you could, please explain as well.
Answer: H2 + MgCl2
Explanation: As they are on the right side of the equation/ are the products being made as a result of the reaction, they are the products.
how can you tell from the name the types of bonds present in a hydrocarbon?
Answer:
Alkane
Alkene
Alkyne
Explanation:
Alkane=1 bond (Saturated hydrocarbon)
Alkene= 2 bonds (Unsaturated hydrocarbon)
Alkyne= triple bonds (Unsaturated hydrocarbon)
Formula of Alkane = CnH2n+2
Formula of Alkene = CnH2n
Formula of Alkyne = CnH2n-2
what is freshly prepared FeSO4 used in the brown ring test
Answer:
Freshly prepared ferrous sulphate is used in brown ring test, because if FeSO4 is stored or it is the old one then it reacts with atmospheric oxygen and gets oxidized to form a corrosive brown-yellow coating of basic ferric sulphate, which is an adduct of ferric oxide and ferric sulphate
HEYA FRIEND
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HERE'S YOUR ANSWER
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It is used in brown ring test because , if Fe2So4 is stored or it is old one then it reacts with atmospheric oxygen and gets oxidized to form a corrosive brown yellow coating of basic ferric sulphate , which is an adduct of ferric oxide and ferric sulphate.
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HOPE IT WILL HELP YOU UP
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KATË
Describe one way in which uranium is disposed of.
Answer:
In the oxide form, uranium can be disposed of as low-level radioactive waste at an approved disposal facility. Approximately 350,000 tons of anhydrous HF are used annually in the United States.
Explanation:
