Answer:
0.016 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\[/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
We have
[tex]n = \frac{9.83 \times {10}^{21} }{6.02 \times {10}^{23} } \\ = 0.01632...[/tex]
We have the final answer as
0.016 molesHope this helps you
What is the difference between chemical change and physical change
Answer:
In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed.
What is the Same about carbohydrates, proteins , and fats ?
Answer:
The main similarity between carbohydrates, proteins and fats is that they are all used for energy.
Explanation:
I hope this helps, have a blessed day.
what happens to gas molecules as the pressure is increased while the temperature and volume of the container remain constant according to the kinetic molecular theory
Answer:
According to the kinetic molecular theory of gases, the average speed and kinetic energy of gas molecules would INCREASE.
Explanation:
In the kinetic molecular theory of gases, assumptions were made based on macroscopic properties of gas (pressure, volume and temperature) which are as a result of the microscopic properties like the position and the speed of the gas molecules. The kinetic molecular theory explains the behaviour of gases through the following 5 assumptions made about an ideal gas;
--> Molecules of a gas are in constant and rapid motion in straight lines until they collide with one another and with the walls of their containers.
--> The actual volume occupied by the had is negligible compared with the volume of the container.
--> Forces of attraction or repulsion between the molecules of a gas are negligible
--> The collision between the molecules is perfectly elastic.
--> The average kinetic energy of the gas molecules is proportional to the temperature of the gas.
Because gas molecules are in constant motion, it has kinetic energy which can be altered when there is increase in pressure. An increase in pressure will cause gas molecules to collide more frequently with one another. This in turn leads to increase in average speed and the kinetic energy of the individual molecules.
If 6.75 g of NaOH are dissolved in 50.00 g of water and the temperature increases
from 20.5°C to 47.8 °C.
a. Is this an example of an endothermic or exothermic reaction?
b. What is the q for the reaction? (Remember since the NaOH dissolves in water add the
masses to get the m)
C. How many moles of NaOH are dissolved?
d. What is the AH for the reaction?
Answer: THE STANDARD HEAT OF SOLUTION OF SODIUM HYDROXIDE IN WATER IS -7.68 KJ PER MOLE.
What is the mass of 7.004 x 1023 molecules of calcium chloride?
Answer:
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You and several novice researchers decide to set up some experiments in an attempt to explain why potassium reacts with oxygen to form a superoxide. One of your team members proposes that potassium's capacity to form a superoxide compound is related to a low value for the first ionization energy. If you wanted to validate this hypothesis, indicate two metals other than potassium (in order of increasing atomic number) that you could examine to see if they also form superoxides when reacted with oxygen gas.
Required:
Express your answers as chemical symbols separated by a comma.
Answer:
Rubidium and cesium
Explanation:
It is noteworthy to say here that larger cations have more stable superoxides. This goes a long way to show that large cations are stabilized by large cations.
Let us consider the main point of the question. We are told in the question that the reason why potassium reacts with oxygen to form a superoxide is because of its low value of first ionization energy.
The implication of this is that, the other two metals that can be examined to prove this point must have lower first ionization energy than potassium. Potassium has a first ionization energy of 419 KJmol-1, rubidium has a first ionization energy of 403 KJ mol-1 and ceasium has a first ionization energy of 376 KJmol-1.
Hence, if we want to validate the hypothesis that potassium's capacity to form a superoxide compound is related to a low value for the first ionization energy, we must also consider the elements rubidium and cesium whose first ionization energies are lower than that of potassium.
It takes 53.0 J to raise the temperature of an 11.0 g piece of unknown metal from 13.0∘C to 24.3 ∘C. What is the specific heat for the metal?
Answer:
51 = ( 8.2/1000)Kg ×S (11.5)
51×1000= 8.2 (11.5)S
S = 51000/94.3
S = 540.8 J/kg K
Explanation:
g A student determines the number of moles of water in a hydrated metal oxide by weighing a clean, dry crucible and lid while the crucible is empty, then reweighing the crucible and lid with a sample of the hydrate, heating the crucible and lid with a Bunsen burner and then reweighing the crucible and lid with the sample after cooling to room temperature. Which error will result in too high a value for the amount of water of hydration
The question is incomplete, the complete question is;
A student determines the number of moles of water in a
hydrated metal oxide by weighing a clean, dry crucible
and lid while the crucible is empty, then reweighing the
crucible and lid with a sample of the hydrate, heating the
crucible and lid with a Bunsen burner and then
reweighing the crucible and lid with the sample after
cooling to room temperature. Which error will result in
too high a value for the amount of water of hydration?
(A) The heating is conducted only once instead of the
three times recommended by the procedure.
(B) The lid is left off the crucible when it is weighed
with the hydrated oxide.
(C) The metal oxide reacts partially with oxygen in the
air, forming a compound in a higher oxidation state.
(D) Some of the heated oxide is spilled from the crucible
before it can be weighed.
Answer:
(D) Some of the heated oxide is spilled from the crucible
before it can be weighed.
Explanation:
It is possible to determine the number of moles of water in a hydrated metal oxide by weighing a clean, dry crucible and lid while the crucible is empty, then reweighing the crucible and lid with a sample of the hydrate. The crucible and lid with the sample are heated, cooled and reweighed.
As this process is going on, suppose some of the heated oxide is spilled from the crucible, then the mass of heated or anhydrous oxide decreases leading to a consequent increase in the number of moles of water in the hydrated metal oxide, hence the answer above.
The too high a value for the amount of water of hydration error is occur due to heating of given hydrated sample.
What is hydrated compounds?
Hydrated compounds are those compounds in which water molecule is present with the normal compound.
To get the correct value of weight of hydrated compound, first we have to weigh the empty crucible and lid and then with sample of compound in the crucible and lid. After this substract empty weigh of crucible & lid from the sample-crucible-lid weigh. If we substract the weigh from heated sample crucible and lid, then we get the error because the hydrated water molecule may decompose due to heating and moles of water increases.
Hence, error will occur if we heat the sample.
To know more about hydrated compound, visit the below link:
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Pls help ASAP it’s timing meeee!!!!!
A generator makes electricity from _____.
chemical reactions
kinetic energy
heat
friction
The breakdown of proteins produces
A. Carbon dioxide
B. Urea
C. Water
Answer:
B.Urea
Explanation:
When an amino acid is broken down, the nitrogen it contains is converted into urea by the liver which then is excreted via the kidneys.
Answer:
urea
Explanation:
when u eat proteins the body breaks them down into amino acids . Ammonia is produced from leftover amino acids and it must be removed from the body. the liver produces many chemicals (enzymes) that change ammonia into a form called ureas
in which block does chlorine lies
Answer:
P-block
Explanation:
Chlorine
Atomic number (Z) 17
Group group 17 (halogens)
Period period 3
Block p-block
Answer:
What does "in which block does chlorine lies"? That question has no way to answer it because there is no question content lol
Explanation:
Share what you have learned about first aid to your family......
please help me with this.
Answer:
[tex] \huge\pink{ \mid{ \underline{ \overline{ \tt Answer :- }} \mid}}[/tex]
=> First Aid enables you to assist persons who become injured in the event of an accident or emergency situation until help arrives.
[tex] \huge\blue{ \mid{ \underline{ \overline{ \tt Situations :- }} \mid}}[/tex]
=> If an accident happens in the workplace, in your home or in a public space, you can use the help of a first aid kit.
=> In situations such as when someone ingests a harmful substance, suffers from a heart attack, a seizure or stroke, is involved in a motor vehicle accident or is caught in a natural disaster, a person trained and knowledgeable in even the very basics of First Aid can be of extreme importance in assisting the injured person(s) until emergency responders arrive.
If you have 4 molecules of FeCl3 and an unlimited supply of NaOH, how
many molecules of NaCl can you produce given the following balanced
equation?
FeCl3 + 3NaOH --> Fe(OH)3 + 3NaCl
Answer:
12 molecules of NaCl
Explanation:
The term "unlimited supply of NaOH" means that NaOH is the reactant in excess hence FeCl3 is the limiting reactant that controls the amount of product formed.
Thus;
From the balanced reaction equation;
1 molecule of FeCl3 yields 3 molecules of NaCl
Hence;
4 molecules of FeCl3 yields 4 * 3/1 = 12 molecules of NaCl
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Which of the following things is not made of wither fermentation?
Cheese
Yogurt
Bread
Peanut butter
Chocolate
What does the dash mark of the 1800s style periodic table represent and tell the original name for element 68
Answer: element 68 is Erbium, should there be a picture attached?
Explanation:
how many moles of an NH3 can be produced from 2.82 moles of nitrogen in the following reaction:
The direct transfer of thermal energy between particles of
matter that are touching is called
Answer:
conduction
Explanation:
In both industry and research there are often times when one particular component of a mixture needs to be separated from a solution. Maybe it is a rare metal that is dissolved in a mixture of minerals. Maybe it is a particular protein from lysed plant cells. If the desired component is volatile, distillation could be used. But if the goal is to separate ions in solution, fractional precipitation is preferred.
a. True
b. False
Answer:
a. True
Explanation:
Distillation process is a process that is used to separate the components or the substances from the liquid mixtures by using selectively boiling and condensation.
While fractional precipitation is a process which separates the ions from solution based on the different solubilities.
Therefore, the answer is true.
In the graph above, what is the relationship between volume and temperature? Does this data support Charles' Law?
Hint: is it a direct or inverse relationship? How does volume change with temperature changes?
Answer:
No the graph does not support Charles' Law. Both volume and temperature increase so it would be a direct relationship.
Explanation:
Why do we have a leap year in our calendar every four years?
Answer:
every 4 years we add an extra day, February 29th, to our calendars these extra days called leave days help synchronize our human created calendars with us orbit around the sun and the actual passing of our seasons
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Answer:
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pls give brainlyest
Explanation:
200 IQ intellectual right here ^^
When H2(g) reacts with F2(g) to form HF(g) , 542 kJ of energy are evolved for each mole of H2(g) that reacts. Write a balanced thermochemical equation for the reaction with an energy term in kJ as part of the equation.
Answer:
H₂(g) + F₂(g) ⇒ 2 HF(g) ΔH°rxn = -542 kJ
Explanation:
Let's consider the unbalanced equation that occcurs when H₂(g) reacts with F₂(g) to form HF(g).
H₂(g) + F₂(g) ⇒ HF(g)
In order to get the balanced equation, we will multiply HF(g) by 2.
H₂(g) + F₂(g) ⇒ 2 HF(g)
To convert a balanced equation into a thermochemical equation, we need to add the standard enthaply of the reaction, considering that 542 kJ of energy are evolved for each mole of H₂(g) and there is 1 mole of H₂(g) in the balanced equation. By convention, when energy is released, it takes a negative sign. The thermochemical equation is:
H₂(g) + F₂(g) ⇒ 2 HF(g) ΔH°rxn = -542 kJ
5. A 23.9 g piece of metal heated to 97.8 °C is placed in 52.4 g water at 21.9 °C. After the
metal is added, the temperature of the water rises to 29.9 °C. Calculate the specific heat of the
metal. Express your answer in the units of cal/g°C.
Answer:
Explanation:
Here we'll use our formula for specific heat, Q=mcΔT.
Q= Heat (Joules), m=mass (g), c=specific heat
ΔT= (final temperature - initial temperature)
When we add a heated piece of metal in water at a lower temperature, the metal will lose heat and the water will absorb that heat. Over time they will eventually reach an equilibrium, here we have it at 21.9 C. If you recall in thermodynamics, , when we lose heat it is exothermic and the values of exothermic reactions are negative, and the values of endothermic reactions are positive. So we can say the heat of the metal is exothermic and releasing heat into the water until they reach equilibrium, thus they are equal. Keeping in mind Q= heat,
-Q metal = Q water.
We can expand this equation to -mcΔT= mcΔT.
Our equation reflects what is happening to the metal and the water.
Before we start, it might be helpful to remember that the
c=specific heat of water= 4.186 J/g C
Let's plug in what we know and solve for c=specific heat of metal. I'll start with the left side then go to the right side.
-(23.9g)(c)(29.9-97.8) = (52.4g)(4.184)(29.9 - 21.9)
-(23.9gc)(29.9-97.8) = (52.4g)(4.184)(29.9 - 21.9)
-(23.9g)(c)(-67.9) = (52.4g)(4.184)(29.9 - 21.9)
1623c = (52.4g)(4.184)(29.9 - 21.9)
1623c = (52.4g)(4.184)(8)
1623c = 1754
c= [tex]\frac{1754}{1623}[/tex]
c= 1.08
This means it takes less heat to raise the temperature of the piece of metal ( in comparison to the water, which require more ).
What unit should you think of when using coefficients?
Answer:
Far as I know coefficients are unitless. sorry if this don't help ;)
What is the IUPAC name of the following compound?
Answer:
2,6–dimethylcyclohexanol
Explanation:
To name the compound given in the question above, we must first obtain the following:
1. Determine the functional group of the compound.
2. Locate the longest continuous carbon chain.
3. Identify the substituent group attached to the compound.
4. Locate the position of the substituent group.
5. Combine the above to obtain the name of the compound.
Now, we shall determine the name IUPAC name of the compound. This can be obtained as follow:
1. The compound contains the –OH group. Thus, the compound is an alcohol.
2. The compound is a cyclic compound with six carbon forming the ring. Thus, the parent name of the compound is cyclohexane. Thus, the presence of the –OH group changes the parent name of the compound to cyclohexanol.
3. The substituent group attached to the compound is methyl (–CH₃)
NOTE: There are two –CH₃ groups attached to the compound.
4. The position of the 1st –CH₃ group is at carbon 2, while the 2nd is at carbon 6.
NOTE: Counting is done from the carbon bearing the functional group.
5. Therefore, the name of the compound is:
2,6–dimethylcyclohexanol
When a certain nuclide undergoes alpha emission, astatine-217 is produced. What is the identity of the nuclide that underwent decay?
a. actinium-219
b. francium-217
c. francium-221
d. astatine-221
e. actinium-221
Please explain the answer
Answer:
C: francium-221
Explanation:
First of all to get a broader perspective, every isotope of francium usually undergoes decay to form astatine, radium, or radon.
Now, Francium-223 and francium-221 are it's only isotopes that occur in nature.
However, francium-221 is the one that undergoes alpha decay to produce astatine-217.
Si tengo 56 gramos de amoniaco gaseoso (NH3) ¿Cuántos moles y moléculas (entidades elementales) podré obtener?
Answer: 56 grams of gaseous ammonia (NH3), has 3.28 moles and [tex]19.80 \times 10^{23}[/tex] molecules.
Explanation:
Given: mass of [tex]NH_3[/tex] = 56 g
Molar mass of [tex]NH_3[/tex] is 17.03 g/mol.
As moles of a substance are its mass divided by the molar mass. Therefore, moles of [tex]NH_3[/tex] are calculated as follows.
[tex]No. of moles = \frac{mass}{molar mass}\\= \frac{56 g}{17.03 g/mol}\\= 3.28 mol[/tex]
According to the mole concept, 1 mole of every substance contains [tex]6.022 \times 10^{23}[/tex] molecules. Hence, number of molecules present in 3.28 moles of [tex]NH_3[/tex] are calculated as follows.
[tex]No. of molecules = no. of moles \times 6.022 \times 10^{23}\\= 3.28 mol \times 6.022 \times 10^{23}\\= 19.80 \times 10^{23}[/tex]
Therefore, we can conclude that 56 grams of gaseous ammonia (NH3), has 3.28 moles and [tex]19.80 \times 10^{23}[/tex] molecules.
Consider the following data on some weak acids and weak bases
acid
Ka
name formula
acetic acid
HCH3CO2
1.8 x10−5
hydrocyanic acid
HCN
4.9 x 10−10
base
Kb
name formula
pyridine
C5H5N
1.7 x 10−9
ammonia
NH3
1.8 x 10−5
Use this data to rank the following solutions in order of increasing pH. In other words, select a '1' next to the solution that will have the lowest pH, a '2' next to the solution that will have the next lowest pH, and so on.
a. 0.1M NaCH3CO2
b. 0.1M NH4Br
c. 0.1M NaBr
d. 0.1M KCN
Answer:
b < c < a < d
Explanation:
The weak acid with the lowest pKa will be the most acidic. In the other way, the conjugate base which the acid is weak will be strong.
The weak base with the lowest pKb will be the most basic. And the conjugate base of the weak base will be a strong acid.
Ka Acetic acid = 1.8x10-5
Ka HCN = 1.9x10-10
Kb pyridine = 1.7x10-9
Kb NH3 = 1.8x10-5
NH4Br is the conjugate base of a weak base. That means is a strong acid.
NH4Br has the lowest pH
NaBr is the conjugate base of a strong acid, HBr. That means NaBr is neutral
The most basic between the conjugate base of the acetic acid, NaCH3CO2 and KCN is KCN because the acetic acid is the stronger acid regard to HCN.
The rank is:
NH4Br < NaBr < NaCH3CO2 < KCN
b < c < a < dThe shadow of a groundhog ( or anything else ) is determined what?
The size, length, and height of the figure are the main factors which determine the shadow of a organism.
The size, length, and height of the figure are the main factors which determine the shadow of a organism.
What is a shadow?A shadow is a dark area where light from a light source is blocked by an opaque object. It occupies all of the three-dimensional volume behind an object with light in front of it. The cross section of a shadow is a two-dimensional silhouette, or a reverse projection of the object blocking the light.
A point source of light casts only a simple shadow, called an "umbra". For a non-point or "extended" source of light, the shadow is divided into the umbra, penumbra, and antumbra. The wider the light source, the more blurred the shadow becomes. If two penumbras overlap, the shadows appear to attract and merge. This is known as the shadow blister effect.
Learn more about shadow,here:
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