Answer:
The answer to your question is 131.43 grams of MgBr₂
Explanation:
Data
number of grams = ?
number of atoms = 4.3 x 10²³
Molecule = MgBr₂
Process
1.- Calculate the molar mass of MgBr₂
MgBr₂ = 24.3 + (79.9 x 2) = 24.3 + 159.8 = 184.1 g
2.- Use proportions to calculate the number of atoms
184.1 g of MgBr₂ -------------- 6.023 x 10²³ atoms
x -------------- 4.3 x 10²³ atoms
x = (4.3 x 10²³ x 184.1) / 6.023 x 10²³
x = 7.92 x 10²⁵ / 6.023 x 10²³
x = 131.43 grams
A solution is prepared by dissolving 15.0 g of NH3 in 250 g of water. The density of the resulting solution is 0.974 g/mL. The mole fraction of NH3 in the solution is _____.A) 16.8B) 0.940C) 0.0597D) 0.922E) 0.0640
Answer:
Mole fraction of [tex]NH_{3}[/tex] in solution is 0.0597.
Explanation:
Molar mass of [tex]NH_{3}[/tex] = 17.031 g/mol
Molar mass of [tex]H_{2}O[/tex] = 18.015 g/mol
No. of moles = (mass)/(molar mass)
So, 15.0 g of [tex]NH_{3}[/tex] = [tex]\frac{15.0}{17.031}[/tex] moles of [tex]NH_{3}[/tex] = 0.8807 moles of [tex]NH_{3}[/tex]
250 g of [tex]H_{2}O[/tex] = [tex]\frac{250}{18.015}[/tex] moles of [tex]H_{2}O[/tex] = 13.88 moles of [tex]H_{2}O[/tex]
So, Mole fraction of [tex]NH_{3}[/tex] in the solution = (no.of moles of [tex]NH_{3}[/tex] )/(total no. of moles) = [tex]\frac{0.8807}{0.8807+13.88}[/tex] = 0.0597
Hence, mole fraction of [tex]NH_{3}[/tex] in solution is 0.0597.
Looking at the heating curves for water (H2O) and ethyl alcohol (C2H5OH), formulate an explanation for the difference in heats of vaporization (2260 J/g for water and 854 J/g for ethyl alcohol).
Answer:
A)They both exhibit hydrogen bonding. However, water has more hydrogens available for hydrogen bonding. Therefore, it requires more heat energy to convert it from a liquid to a gas
Explanation:
USA Test Prep Answer
a reseacher observes a vehicle with a inital velocity of 14m/s. the vehicle accelerates uniformly with a acceleration of 3 m/s2. after 6 seconds ,what is the velocity of the vehicle?
Answer:
32m/s
Explanation:
the explanation is in the picture
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Which is the correct order of increasing standard molar entropy for the noble gases?
He ≤ Ne ≤ Kr ≤ Ar
He ≤ Ne ≤ Ar ≤ Kr
Ne ≤ He ≤ Ar ≤ Kr
Kr ≤ Ar ≤ Ne ≤ He
Answer:
The correct order of increasing standard molar entropy for the noble gases is He ≤ Ne ≤ Ar ≤ Kr
Explanation:
Entropy is the measure of degree of disorderliness or randomness of a substance. Entropy increases with increasing number of electron present in an atom due to increased repulsive force of the electrons. Therefore, the standard entropy of a substance increases with an increase in their atomic masses.
For the given noble gases in this question, Helium (He) has the least atomic mass while Krypton (Kr) has the highest atomic mass.
Thus, the correct order of increasing standard molar entropy for the noble gases is He ≤ Ne ≤ Ar ≤ Kr
Final answer:
The increasing standard molar entropy for noble gases is He ≤ Ne ≤ Ar ≤ Kr, due to growing atomic number and electronic complexity down the group.
Explanation:
The correct order of increasing standard molar entropy for the noble gases is He ≤ Ne ≤ Ar ≤ Kr. This is because entropy generally increases with atomic number due to increased electronic complexity and atomic mass. As you move down the group in the periodic table, noble gases have more electrons that can occupy a greater volume of space and therefore have higher entropy.
what is the formula for tetrabromine decafluoride
Answer:
[tex]Br_{4}F_{10}[/tex]
The prefix "Tetra" implies 4 Bromine atoms. The prefix "Deca" implies 10 fluorine atoms.
How many moles are in 4.20 g of SO2?
Answer:
0.066 mole SO₂
Explanation:
moles = mass in grams / formula weight
= 4.2g/64g/mol = 0.066 mole SO₂
What is the dropping of a sediment called
Answer:Deposition is the dropping of sediment by wind, water, ice, or gravity.
Explanation:
When thermal energy is added to a substance, its temperature increases, which can change its state from solid to liquid
Answer:
The dropping of a sediment is called deposition.If a sample gas is collected over water. The atmospheric pressure is 778 mm and the temperature is 30°C. If the vapor pressure of water at 30 C is 31.8 mm, what is the pressure of the gas?
Answer:
P = 746.2 mmHg or 0.9818 atm
Explanation:
First, we have a sample gas (This can be hydrogen, argon, nitrogen or any other gas) that was collected with a pressure of 778 mmHg. We also know the vapor pressure which is 31.8 mmHg. To get the pressure that the gas is exerting, we can assume that the atmospherical pressure is the total pressure of the whole system. Therefore we can use the following expression:
Pt = Pw + Pg (1)
Where:
Pt: total pressure
Pw: water pressure
Pg: gas pressure
From (1) we can solve for the gas pressure and have:
Pg = Pt - Pw
Replacing the data we have:
Pg = 778 - 31.8
Pg = 746.2 mmHgThis would be the pressure of the gasIf you want this value in atm, you should divide it by 760 mmHg (Conversion from mmHg to atm):
Pg = 746.2 / 760
Pg = 0.9818 atmBromelain works by breaking the enzymes that cause browning into smaller molecules. Explain how the reaction that breaks up the enzymes occurs.
Bromelain separates the amino acids in the enzymes that cause browning by breaking the peptide bonds. The pH of a solution determines the charge of certain R groups.
Amino acids are defined as the substances which are considered to be the monomers of proteins.Every amino acid has the same structure consisting of a central carbon which is bonded to an amino group , carboxyl group and a hydrogen.
Each amino acid also has another atom or a group of atoms bonded to the alpha carbon which are also known as the R group or the variable group of the side chain.There are 20 common amino acids present in natural proteins and each amino acid has the same backbone.
Learn more about amino acids,here:
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Choose all of the correct statements concerning acids and bases.
Addition of base into the water increase hydronium ion concentration of the solution is a false statement other 4 are correct.
Explanation:
An acid is referred to as substance that is denoting hydrogen ion. A base is referred to as a substance that is accepting hydrogen ions. Certain examples of acids are sulphuric acid, citric acid and certain examples of bases are ammonia as well as bleach. The difference that occur between the acid and the base is due to its pH. Acids have the ability to neutralize the base.Answer: 1, 2 and 5
Explanation:
did usatestprep
Explain how temperature can affect the speed of reaction. Give an example.
Answer:
Chemical reactions proceed at different rates. The factors that affect reaction rates are:
surface area of a solid reactant
concentration or pressure of a reactant
temperature
nature of the reactants
presence/absence of a catalyst.
A change in one or more of these factors may alter the rate of a reaction. In this lesson, you will define these factors, and describe and predict their effects on reaction rates.
Surface Area
Surface area is the exposed matter of a solid substance.
Imagine that you are holding a perfect cube of magnesium. The surface area is the sum of the area of all six sides of the cube. The surface area of the cube can be increased by dividing the cube into smaller cubes. Surface area is maximized when a single large cube is crushed to fine powder.
The rate of reaction of a solid substance is related to its surface area. In a reaction between a solid and an aqueous/liquid/gas species, increasing the surface area of the solid-phase reactant increases the number of collisions per second and therefore increases the reaction rate.
In a reaction between magnesium metal and hydrochloric acid, magnesium atoms must collide with the hydrogen ions. When the magnesium atoms form one big lump...
The concentration of a gas is a function of the pressure on the gas. Increasing the pressure of a gas is exactly the same as increasing its concentration. If you have a certain number of gas molecules, you can increase the pressure by forcing them into a smaller volume.
Under higher pressure or at a higher concentration, gas molecules collide more frequently and react at a faster rate. Conversely, increasing the volume of a gas decreases pressure which in turn decreases the collision frequency and thus reduces the reaction rate.
It is important to note however that there are reactions involving gases in which a pressure change does not affect the reaction rate. For this reason, the rates of reactions involving gases have to be determined by experiment.
Also note that solids and liquids are not affected by pressure changes.
Need a good analogy for the effect of concentration on the rate of a chemical reaction?
Temperature
With the exception of some precipitation reactions involving ionic compounds in solution, just about all chemical reactions take place at a faster rate at higher temperatures. The question is why?
Temperature (in Kelvin degrees) is proportional to the kinetic energy of the particles in a substance. For example, if the Kelvin temperature of a substance is doubled, then the average kinetic energy of the particles in that substance is doubled.
At higher temperatures, particles collide more frequently and with greater intensity.
Here's an analogy.
Imagine that you are baby-sitting a bunch of 6 year olds. You put them in a yard and you let them run around. Every now and then a couple of kids will run into each other. Now imagine that you decide to feed them some sugar. What happens? They run around faster and of course there are many more collisions. Not only that, the collisions are likely to be a lot harder/more intense.
Now, let's look at the effect graphically. Recall that in any sample of matter (the example we used previously was a gas), individual particles have different kinetic energies. Some are moving fast some are moving slowly, and most are moving at some intermediate speed.
Increasing the temperature by say 10°C causes some of the intermediate speed molecules to move faster. The result is more molecules with sufficient kinetic energy to form an activated complex upon collision!
Now consider the relationship between threshold kinetic energy and activation energy. Threshold kinetic energy is the minimum amount of energy required for colliding particles to react - it is the equivalent of activation energy or the minimum potential energy gain required to form an activated complex.
As you can see on the graph, a small increase in temperature can double the number of molecules with the threshold kinetic energy.
Thus there are two effects of increasing temperature: greater collision intensity and more frequent collisions.
A general rule is that a 10°C temperature increase can double a reaction rate. It turns out that the increase in the reaction rate is mainly a function of the more intense collisions. Increased collision frequency is not as significant a factor.
Explanation:
Which 1.0 M solution has the lowest pH?
Answer: nitric acid
Explanation:
The solution with the lowest pH would mean that it is an acid, specifically a strong acid which completely dissociates into ions in aqueous solution. The answer it is nitric acid (HCl) that will have the lowest pH because it is the only strong acid in the group
Which equation represents a single replacement reaction that can occur?
A. 2 Cu + FeSO4 → Fe + Cu2SO4
B. Ag + KNO3 → K+ AgNO3
C. l2 + MgCl2 → Cl2 + Mgl2
D. K+ NaF → KF + 2 Na
Consider the following errors that could be made when running TLC. Indicate what should be done to correct the error. a. A two-component mixture containing 1-octene and 1, 4-dimethylbenzene gave only one spot with an Rf value of 0.95. The solvent used was acetone.
Final answer:
To correct a high Rf value of 0.95 in TLC, decrease the polarity of the mobile phase by using a less polar solvent and ensure the sample is not too concentrated for improved separation and accurate Rf values.
Explanation:
When running Thin Layer Chromatography (TLC), a high Rf value of 0.95 implies that the sample has moved almost as far as the solvent front, suggesting that the mobile phase is too polar. To correct this and achieve better separation, the polarity of the mobile phase should be decreased.
Using a less polar solvent, such as a mixture of hexanes and ethyl acetate, instead of pure acetone might provide better separation of the components 1-octene and 1, 4-dimethylbenzene.
Additionally, ensuring that the samples are not too concentrated can lead to more accurate Rf values and better spot definition. A correctly run TLC should show the desired component with an Rf around 0.35, separated from other spots by at least 0.2 Rf units.
Given the reactant side of the total ionic equation for the neutralization reaction of ammonium hydroxide (NH4OH) with hydrochloric acid (HCl), write the total ionic equation (also known as the complete ionic equation) by entering both the reactant and the product species, separated by the reaction arrow.
Final answer:
The total ionic equation for the neutralization reaction of ammonium hydroxide with hydrochloric acid expresses all components as ions and after removing spectator ions, the net ionic equation is OH⁻(aq) + H⁺(aq) → H₂O(l).
Explanation:
To write the total ionic equation for the neutralization reaction of ammonium hydroxide (NH₄OH) with hydrochloric acid (HCl), we need to express all soluble substances as ions. Ammonium hydroxide can be represented as NH₄⁺(aq) and OH⁻(aq) since it partially dissociates in solution. The hydrochloric acid fully dissociates into H⁺(aq) and Cl⁻(aq).
The total ionic equation is as follows:
NH₄⁺(aq) + OH⁻(aq) + H⁺(aq) + Cl⁻(aq) → NH₄⁺(aq) + Cl⁻(aq) + 2H₂O(l)
The net ionic equation, which shows the actual chemical change, is produced by removing the spectator ions (NH₄⁺ and Cl-), resulting in: OH⁻(aq) + H⁺(aq) → H₂O(l)
Final answer:
The total ionic equation for the neutralization reaction between ammonium hydroxide and hydrochloric acid is NH4+(aq) + OH-(aq) + H+(aq) + Cl-(aq) → NH4+(aq) + Cl-(aq) + H2O(l), with H+(aq) + OH-(aq) → H2O(l) as the net ionic equation.
Explanation:
The total ionic equation for the neutralization reaction of ammonium hydroxide (NH4OH) with hydrochloric acid (HCl) shows each species in its ionic form. The reactants ammonium hydroxide and hydrochloric acid dissociate in water to form NH4+ (aq), OH- (aq), H+ (aq), and Cl- (aq). In a complete ionic equation, all of the ions are shown as they exist in solution before and after the reaction:
NH4+ (aq) + OH- (aq) + H+ (aq) + Cl- (aq) → NH4+ (aq) + Cl- (aq) + H2O(l)
After the reaction, ammonium ions and chloride ions remain in solution while water is formed as the product. However, since ammonium ions (NH4+) are spectator ions in this reaction, they can be omitted to provide the net ionic equation:
H+ (aq) + OH- (aq) → H2O(l)
The net ionic equation indicates that the hydrogen ions (H+ from the hydrochloric acid) combine with the hydroxide ions (OH- from the ammonium hydroxide) to form water, which is a characteristic outcome of a neutralization reaction.
Define dissolve in your own words
Answer:
Dissolve: to terminate a union of multiple members actively, as by disbanding
Extend your thinking: Why do you think the temperature does not change much during a phase change? If possible, discuss your answer with your classmates and teacher.
Answer:
The rate of temperature change does not stay constant and decreases over time because the temperature difference decreases over time.
Explanation:
The temperature difference is due to Thermal Equilibrium
Where does filtration of the blood occur within the kidneys?
Answer:
takes place in the glomerulus
Explanation:
which is the vascular beginning of the nephron . Approximately one-fourth of the blood flow from cardiac output circulates through the kidney, the greatest rate of blood flow for any organ .
The filtration of the blood in the kidneys occurs in the glomerulus, where most solutes are filtered out by glomerular filtration.
Filtration of the Blood in the Kidneys:
The filtration of the blood in the kidneys primarily occurs in the glomerulus. The glomerulus is a network of capillaries at the beginning of a nephron. When blood flows through the glomerulus, most solutes, except for proteins, are filtered out into the glomerulus by a process called glomerular filtration. The filtrate is then collected in the renal tubules, where it undergoes further processing to form urine.
This process begins with glomerular filtration, continues with tubular reabsorption in the proximal convoluted tubule (PCT), and ends with tubular secretion. Finally, the collecting ducts gather the filtrate, now called urine, which is passed on to the ureters and then eliminated from the body.
In 1939, at the age of 20, a man stood 270 cm tall (over 8 1/2 feet) and wore size 37 shoes! The hormonal disorder from which he suffered is known as giantism. Too much of what hormone produced his condition?
Answer:
Somatotropin(Growth Hormone)
Explanation:
-Uncontrolled growth in a person is usually caused by the excessive secretion of growth hormone.
-This hormone is also known as Somatotropin.
-This hormone is produced in the pituitary gland.
2. A 0.5 kg tennis ball has speed of 15m/s. what is the kinetic energy of tennis?
Explanation:
Given
mass (m) = 0.5 kg
velocity (v) = 15 m/s
Now
Kinetic energy
= 1/2 *m*v²
= 1/2 * 0.5 * 12²
= 0.5 *0.5 * 144
= 36 joule
hope it will help
Which statements are true? Check all that apply.
Alpha decay emits the same number of protons and neutrons
Beta decay always emits protons.
Beta decay always emits electrons.
Gamma rays are particles of fast-moving matter
Gamma rays are a form of electromagnetic radiation.
DONE
Answer:
A and E
Alpha decay emits the same number of protons and neutrons
Gamma rays are a form of electromagnetic radiation
Explanation:
Just did this one e2020 :)
Answer:
a and e
Explanation:
edge
We eat food for energy. What is the source of energy for this food chain?
uiz: Types of Chemical Reactions 11:Chemical Reactions 10. In a double-replacement reaction, _____. the reactants are usually a metal and a nonmetal one of the reactants is often water the reactants are generally two ionic compounds in aqueous solution energy in the form of heat or light is often produced
complete question:
In a double-replacement reaction , _____.
a. the reactants are usually a metal and a nonmetal
b.one of the reactants is often water the reactants
c. the reactants are generally two ionic compounds in aqueous solution
d. energy in the form of heat or light is often produced
Answer:
c. the reactants are generally two ionic compounds in aqueous solution
Explanation:
A double replacement reaction is a kind of chemical reaction where two compounds reacts and the cations and anions of the reacting compound exchange places to form two new compound or products.
The double replacement reaction is also known as a double displacement reaction. A precipitate is usually form in this kind of reaction. The two reactant that takes place in this reaction are ionic in nature. Example of a double replacement reaction is the reaction between silver nitrate and sodium chloride to precipitate silver chloride and produce a soluble sodium nitrate.
AgNO3 + NaCl → AgCl + NaNO3 .
The sodium cation replace Ag in it compound while Ag replace Na in it compound. The anions also exchange places too.
A gas that has a pressure of 2 atm and
a volume of 10 L. What would be the
new volume if the pressure was
changed to 1 atm?
Answer:
The answer to your question is 20 liters
Explanation:
Data
Pressure 1 = P1 = 2 atm
Volume 1 = V1 = 10 l
Pressure 2 = P2 = 1 atm
Volume 2 = V2 = ?
Process
To solve this problem use Boyle's law
P1V1 = P2V2
-Solve for V2
V2 = P1V1/P2
-Substitution
V2 = (2 x 10)/1
-Simplification
V2 = 20/1
-Result
V2 = 20 l
A gas at 155 Kpa and 25 degrees celsius has a volume of 1 L. The pressure increases to 605 kPa as the temperature is raised to 125 degrees Celsius what is the new volume?
Answer:
The answer to your question is V2 = 0.34 l
Explanation:
Data
Pressure 1 = P1 = 155 kPa
Temperature 1 = T1 = 25°C = 298°K
Volume 1 = V1 = 1 l
Pressure 2 = P2 = 605 kPa
Temperature 2 = T2 = 125°C = 398°K
Volume 2 = V2 = ?
Process
To solve this problem use the Combined gas law.
P1V1/T1 = P2V2/T2
-Solve for V2
V2 = P1V1T2 / T1P2
-Substitution
V2 = (155)(1)(398) / (298)(605)
-Simplification
V2 = 61690 / 180290
-Result
V2 = 0.34 l
chemical or physical change? and what made you think such?
Answer:
it's a chemical change and an electrolytic reaction
What is the change in entropy that occurs in the system when 1.00 mol of methanol (ch3oh) vaporizes from a liquid to a gas at its boiling point (64.6 ∘c)? for methanol, δhvap=35.21kj/mol. what is the change in entropy that occurs in the system when 1.00 of methanol () vaporizes from a liquid to a gas at its boiling point (64.6 )? for methanol, . -545 j/k 104 j/k -104 j/k 545 j/k?
Answer:
104 J/K
Explanation:
First, we have to calculate the heat (Q) involved in the vaporization of 1.00 mol of methanol.
Q = n × ΔH°vap
Q = 1.00 mol × 35.21 kJ/mol = 35.2 kJ
Then, we have to convert the boiling point to Kelvin.
K = °C + 273.15
K = 64.6 + 273.15 = 337.8 K
Finally, we calculate the change in the entropy associated with this process.
ΔS = Q/T
ΔS = 35.2 kJ/337.8 K = 0.104 kJ/K = 104 J/K
Select the compounds from the list below which are insoluble in water
HCl, NH3, NaClO3, BaSO4, AgNO3, PbCl2, Cu2O, CuSO4, Pb(C2H3O2), AgBr
Answer:
Insoluble in water:
BaSO4PbCl2Cu2OAgBrExplanation:
Water turns out to be a good solvent for ionic substances, or in general, polarized covalent substances. On the other hand, it is not a good solvent for non-polar substances, these being the vast majority of covalent substances.
What could cause damage to your bike’s wheel?
A) twisting the tube around the wheel
B) riding your bike with a flat tire
C) air escaping from the tube
D) under-inflating the tire
When focusing on nearby objects, the highlighted structure: __________.
1. becomes flatter
2. gains fluid from surrounding aqueous humor
3. does not change shape
4. becomes rounder
Answer:
The correct option is;
4. becomes rounder
Explanation:
The ciliary muscles in the eye controls the shape of the lens when looking at objects located at different positions. A close by object such as a book that appears large and the eye has to capture the light from wide angles and therefore the lens is made more rounded to enable the light rays to be focused for viewing.
Similarly when looking at far objects, the lens changes to become more planar.
Accommodation is the term used to describe the ability of the eye lens to change its focus and shape.