Hello!
To find the mass of helium, we need to multiply the total moles by the mass of helium. We are given 2.714 moles of helium, and the mass of helium is about 4.00 grams. Now, we multiply the two values together to get the grams.
2.714 moles x 4.00 grams = 10.856 grams
According to the number of significant figures, 2.714 moles of helium has a mass of 10.9 grams (exact value: 10.856 grams).
Question 9 Saved
When electron move from an excited state to their ground state a continuous spectrum is emitted.
Question 9 options:
True
False
I believe the answer to this is true.
What is the freezing point of a solution of sugar dissolved in water if the concentration of the solution is 0.24 m
A. -.446
B. .93
C. .446
Hey there!:
Using relation:
Δt = Kf * m
For water , Kf = 1.86 K/molal
Putting values:
Δt = 1.86 * 0.24
Δt = 0.446
So , Freezing point = - 0.446ºC
Answer A
Hope that helps!
The depression in freezing point here for the sugar solution is 0.466 degree Celsius. Hence the freezing point of the sugar solution is -0.446. Hence, option A is correct.
What is freezing point ?Freezing point of a solution is the temperature at which the solution changes from liquid to solid state.
To determine the freezing point of a solution of sugar dissolved in water, we need to use the freezing point depression equation:
ΔTf = Kf × molality
where ΔTf is the change in freezing point, Kf is the freezing point depression constant for the solvent (water in this case), and molality is the concentration of the solution expressed in moles of solute per kilogram of solvent.
Assuming a Kf of 1.86 °C/m for water, and a molality of 0.24 m for the sugar solution, we can calculate the change in freezing point:
ΔTf = 1.86 °C/m × 0.24 m = 0.4464 °C
This means that the freezing point of the solution will be lowered by 0.4464 °C compared to the freezing point of pure water. Since the freezing point of pure water is 0 °C, the freezing point of the sugar solution will be:
0 °C - 0.4464 °C = -0.4464 °C
Therefore, the freezing point of the solution is approximately -0.4464 °C, which is closest to option A. -0.446.
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how would isopropanol behave when poured out of its container onto a table
Isopropanol spread on a table will form a layer that evaporates quickly and may cool the surface or damage materials sensitive to alcohol. It is also flammable, creating a fire risk near open flames or heat sources.
When isopropanol is poured out of its container onto a table, it behaves similarly to how water or other liquids would behave. Due to its low viscosity, isopropanol will spread out across the table's surface, forming a thin layer.
Since isopropanol evaporates much faster than water at room temperature, it would begin to evaporate quickly, leaving behind a cool sensation due to the evaporation process removing heat from the surroundings. If the table is made of a material that can be degraded by alcohol, such as certain plastics or finishes, the isopropanol may also cause damage to the table's surface.
Furthermore, it's important to note that isopropanol is flammable, so if it is poured near an open flame or a heat source, there is a risk of ignition. Therefore, handling isopropanol should be done with caution, and proper ventilation should be ensured to prevent the build-up of flammable vapors.
What is the approximate vapor pressure when the liquid water boils at about 50°C? 230 mmHg 5 mmHg 760 mmHg 380 mmHg
The correct answer is 230 mmHg.
When liquid water boils at 100°C, the water vapor pressure is 760 mmHg
Hence, when liquid water boils at 50°C, the water vapor pressure is (760/2) mmHg or 230 mm Hg.
As the boiling temperature of water halves so does the vapor pressure of water. This is in accordance to Pressure Law.
According to Pressure law, pressure is directly proportional to the absolute temperature, at constant volume.
Answer:
230 mmHg
Explanation:
Which of the following would label the boxes correctly?
Question 1 options:
1) endothermic; 2) exothermic
1) products; 2) reactants
1) reactants; 2) products
1) exothermic; 2) endothermic
What is the pH of a solution with a hydronium (H3O+) concentration of 5.6 × 10-9 M? Use the table to help you.
Answer:
pH = 8.25
Explanation:
pH = -log[H₃O⁺] = -log(5.6 × 10⁻⁹) = 8.25
Answer:
pH of the solution is 8.25 (≅8.3)
Explanation:
Given:
H3O+ ion concentration = 5.6*10⁻⁹ M
To determine:
pH of the given solution
Explanation:
pH is related to the hydronium ion concentration as follows:
[tex]pH = -log[H3O+]\\[/tex]
For the given solution
[tex]pH = -log[5.6*10^{-9}] = 8.25[/tex]
An Ammonia molecule is made up of one nitrogen and 3 hydrogen atoms, it has a formula NH3. What is the mass of one more Ammonia? **Hint find the molar mass of ammonia by adding up all of the masses of the elements in the compound.
The molar mass is the sum of the mass of all the atoms of a particular molecule.
The unit of molar mass is grams per mole.
The atomic mass of H = 1.00
The atomic mass of N = 14.00
The molar mass of ammonia = atomic mass of N + 3 x (atomic mass of H)
= 14.00 + 3 x (1.00) = 17.00
Therefore the molar mass of ammonia is 17g/mol
The correct answer is 17g/mol.
Which of the following statements about Bohr's model of the atom is true? Bohr's model explains the chemical behavior of all atoms.
Bohr’s model does not take into account the interactions multiple electrons would have with one another.
Bohr's model explains the spectra of atoms with more than one electron.
Bohr's model takes into account the interactions multiple electrons would have with one another.
I believe the answer is "Bohr's model explains the chemical behavior of all atoms."
Which two values for `DeltaG` and E°cell correctly indicate a spontaneous reaction?
Well as an spontaneous reaction will have a negative gibbs free energy (delta g) and a positive e cell and also the E cell is also measured in V, then your answer is the first one: ΔG = –295kJ, E°cell = +1.53 v. Hope this works
A sample of gas in a closed container at a temperature of 100.0°C and 3.0 atm is heated to 300.0°C. What is the pressure of the gas at the higher temperature?
Answer:- 4.6 atm.
Solution:- In this problem, the volume is constant and the pressure is changing as the temperature is changed. It's based on Gay-Lussac's law which states that, "At constant volume, pressure of the gas is directly proportional to the kelvin temperature."
The equation used for solving the problems based on this law is:
[tex]\frac{P_1}{T_1}=\frac{P_2}{T_2}[/tex]
Where, [tex]P_1[/tex] is initial pressure and [tex]P_2[/tex] is final pressure.
Similarly, [tex]T_1[/tex] is initial temperature and [tex]T_2[/tex] is final temperature.
[tex]P_1[/tex] = 3.0 atm
[tex]T_1[/tex] = 100.0 + 273 = 373 K
[tex]T_2[/tex] = 300.0 + 273 = 573 K
[tex]P_2[/tex] = ?
Let's plug in the values in the equation and solve it for final pressure:
[tex]\frac{3.0atm}{373K}=\frac{P_2}{573K}[/tex]
[tex]P_2=\frac{(3.0atm*573K)}{373K}[/tex]
[tex]P_2=4.6atm[/tex]
So, the pressure of the gas at higher temperature is 4.6 atm.
Initial temperature of the gas = 100.0°C + 273 = 373 K
Initial pressure of the gas = 3.0 atm
Final temperature of the gas = 300.0°C + 273 = 573 K
According to Pressure Law,
P₁/T₁ = P₂/T₂
where P₁ and T₁ are the initial pressure and temperature respectively, and P₂ and T₂ are the final pressure and temperature respectively.
Plugging in the given data in Pressure Law we have,
3.0 atm/ 373 K = P₂/573 K
P₂ = (3.0 atm x 573 K)/ 373 K
P₂ = 4.6 atm
Thus, the pressure of the gas at the higher temperature is 4.6 atm.
OFFERING 99 POINTS AND BRAINLIEST TO BEST ANSWER!!!
How many valence electrons are in an atom with the electron configuration in example A? Example A: 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 4p^2
A. 22
B. 2
C. 4
D. 6
The x number in ^x indicates the number of electronics in an obit, e.g. 1s^2 means there are 2 electrons in the 1s orbit.
Total number of electrons in A = 2 + 2 + 6 +2 + 6 + 2 + 2
= 22
VALENCE electrons are those in the outer most shell.
In A, there are 4s^2 + 4p^2: 2 + 2 = 4
Answer should be C instead. So sorry for the mistake earlier!
Example A: 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 4p^2
counting e-: 2 2 6 2 6 2 2
2+2+6+2+6+2+2 = 22
ans is A. 22
Thomas has 235 grams of K2S in the chemistry lab. How many atoms of potassium (K) are in 235 grams of the compound?
A.
2.13 × 1023
B.
4.26 × 1023
C.
2.57 × 1024
D.
3.37 × 1024
E.
7.08 × 1024
Answer : The correct option is, (C) [tex]2.57\times 10^{24}[/tex]
Solution for Part 1 : Given,
Mass of [tex]K_2S[/tex] = 235 g
Molar mass of [tex]K_2S[/tex] = 110.262 g/mole
First we have to calculate the moles of [tex]K_2S[/tex].
[tex]\text{Moles of }K_2S=\frac{\text{Mass of }K_2S}{\text{Molar mass of }K_2S}=\frac{235g}{110.262g/mole}=2.13moles[/tex]
Now we have to calculate the number of atoms of potassium in the given compound.
In the given compound, there are 2 atoms of K and 1 atom of S.
As, 1 mole contains [tex]2\times 6.022\times 10^{23}[/tex] number of potassium atoms
So, 2.13 moles contains [tex]2.13\times 2\times 6.022\times 10^{23}=2.57\times 10^{24}[/tex] number of potassium atoms
Therefore, the number of potassium atoms in given compound is, [tex]2.57\times 10^{24}[/tex]
Explanation for Part 2 :
Statement 1 : A balloon shrinks when it's taken outside in the winter.
This statement follow the Charles's law. There is a direct relation between the temperature and volume. As the temperature decreases, the volume also decreases and vice-versa.
Statement 2 : A closed, flexible container expands when it's heated.
This statement follow the Charles's law. There is a direct relation between the temperature and volume. As the temperature increases, the volume also increases and vice-versa.
Statement 3 : When the size of an air chamber is increased, the air pressure decreases.
This statement follow the Boyle's law. There is an inverse relation between the pressure and volume. As the pressure decreases, the volume increases and vice-versa.
Statement 4 : Pressing on an inflated balloon decreases its size.
This statement follow the Boyle's law. There is an inverse relation between the pressure and volume. As the pressure increases, the volume decreases and vice-versa.
Statement 5 : A balloon expands when air is blown into it.
This statement follow the Avogadro's law. There is a direct relation between the number of moles of gas and volume. As the number of moles of air increases, the volume also increases and vice-versa.
Answer:
2.57 x 10^24
Explanation:
This is correct! :)
Validate how valence electrons determine the chemical reactivity of an element: give 2 examples of elements with high reactivity and justify your response.
The movement of organisms into a range is called
A. immigration.
B. emigration.
C. population shift.
D. carrying capacity.
Immigration is the movement of organisms into a population, increasing its size and growth rate. Emigration is the movement out of a population. Carrying capacity is the maximum population size that the environment can sustain. Hence, option A, immigration, is correct.
The movement of organisms into a range is called immigration. Immigration is the movement of individuals into a population from other areas, which increases the population size and growth rate. In contrast, emigration refers to the movement of individuals out of a population's range. When an animal migrates, it does so because it can find resources there or because the habitat is a good fit for it. When an animal emigrates, it signifies that its natural habitat is no longer good for it and that it must find a new one. The definition of population change is a shift in the proportions of the various groups of people that make up a population. Carrying capacity is related to population size as well, but it describes the maximum number of individuals of a species that the environment can support, not the movement into a range. Thus, the correct answer to the question is A. immigration.
What is an ephemeral stream? A)one that flows only after rainfall B) one that flows only in flat lands C) one that is formed only from mechanical weathering D) one that is formed only from chemical weathering
Answer: Option (a) is the correct answer.
Explanation:
The stream that flows during or after the rainfall is called an ephemeral stream. This stream occurs in areas where there is less rainfall or deficiency of moisture.
The stream that flows only in flat lands is called as river.
Mechanical weathering results in the breaking of rocks causes ice wedging.
Chemical weathering results in the change in molecular structure of rocks and soil.
Thus, it can be concluded that option (a) is the correct answer.
Which has more calories: table sugar or aspartame?
A 29.950 g sample of an unknown metal is heated to 100.0 °c. The metal is then poured into 50.0 g of water in an insulated coffee cup calorimeter. The temperature of water rises from 25.0 ºc to 27.7 ºc. What is the specific heat of the metal?
Answer : The specific heat of metal is, [tex]0.261J/g^oC[/tex]
Explanation :
In this problem we assumed that heat given by the hot body is equal to the heat taken by the cold body.
[tex]q_1=-q_2[/tex]
[tex]m_1\times c_1\times (T_f-T_1)=-m_2\times c_2\times (T_f-T_2)[/tex]
where,
[tex]c_1[/tex] = specific heat of unknown metal = ?
[tex]c_2[/tex] = specific heat of water = [tex]4.18J/g^oC[/tex]
[tex]m_1[/tex] = mass of unknown metal = 29.950 g
[tex]m_2[/tex] = mass of water = 50.0 g
[tex]T_f[/tex] = final temperature of water = [tex]27.7^oC[/tex]
[tex]T_1[/tex] = initial temperature of unknown metal = [tex]100^oC[/tex]
[tex]T_2[/tex] = initial temperature of water = [tex]25.0^oC[/tex]
Now put all the given values in the above formula, we get
[tex]29.950g\times c_1\times (27.7-100)^oC=-50.0g\times 4.18J/g^oC\times (27.7-25.0)^oC[/tex]
[tex]c_1=0.261J/g^oC[/tex]
Therefore, the specific heat of metal is, [tex]0.261J/g^oC[/tex]
An atom has 9 electrons and 9 protons at the start . If it loses 2 electrons, the net charge on the atom will be ? If the atom instead gains 4 electrons the net charge will be ?
Answer : If it loses 2 electrons, the net charge on the atom will be (+2) and If it gains 4 electrons, the net charge on the atom will be (-4).
Explanation :
We are given:
Number of electron in an atom = 9
Number of protons in an atom = 9
Atomic number is defined as the number of protons or electrons that are present in a neutral atom.
Atomic number = number of protons = number of electrons
An ion is formed when an atom looses or gains electron.
When an atom looses electrons, it will form a positive ion known as cation.
When an atom gains electrons, it will form a negative ion known as anion.
According to the question,
When the atom loses 2 electrons then the net charge on the atom will be (+2) because it will form a positive ion by losing electrons.
When the atom gains 4 electrons then the net charge on the atom will be (-4) because it will form a negative ion by gains electrons.
What word or two-word phrase best describes the shape of the fluoroform molecule?
The two-word phrase that best describes the shape of the fluoroform molecule is ; Tetrahedral
Fluoroform is a chemical compound represented by the formula CHF₃ which falls within the class of haloforms. The center atom in a fluoroform molecule is the carbon atom which has ( 3 ) C - F bonding and ( 1 ) C - H bonding. This means that the number of electrons is in a fluorocarbon is 4, hence according to VSEPR theory the geometry of the fluoroform molecule will be Tetrahedral.
Hence we can conclude that The two-word phrase that best describes the shape of the fluoroform molecule is ; Tetrahedral
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The shape of the fluoroform molecule is trigonal pyramidal.
Explanation:The shape of the fluoroform molecule is trigonal pyramidal.
A trigonal pyramidal shape occurs when a central atom is bonded to three other atoms and has one lone pair of electrons. In the case of fluoroform (CHCl3), the central carbon atom is bonded to three fluorine atoms and has one lone pair of electrons, resulting in a trigonal pyramidal shape.
Other examples of molecules with trigonal pyramidal shape include ammonia (NH3) and phosphine (PH3).
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J.J. Thomson's experiments supported the existence of a particle that deflected away from a negative charge and toward a positive charge. Ernest Rutherford found that when positive particles were fired at gold foil, some of the particles deflected rather than passing straight through. Taken together, these experiments support our understanding of the
A. Flavors or quarks
B. Structures of the atom
C. Specific gravity of gold
D. Law of Conservation of energy
Which phosphate in this tetranucleotide would be radioactive? Note that the phosphates are numbered 1-4 in red from top to bottom?
The phosphodiester bonds contains a sugar attached to a phosphate group. Since one outermost phosphate is used to form a phosphate bond everytime, from a precursor containing innermost radiolabelled phosphate, the third phosphate groups will be radioactive in nature. So correct answer is 3.
Hope that helps!
Multichoice
When a double displacement reaction takes place, one of the products must be _____.
1. a salt
2. a gas
3. a precipitate
4. water
Answer: The correct answer is Option 1.
Explanation:
A double displacement reaction is defined as the reaction in which exchange of ions takes place. The general equation for the reaction follows:
[tex]AB+CD\rightarrow AD+CB[/tex]
During this reaction, one of the product formed is always a salt.
A gas is formed in a single displacement reaction and not in double displacement reaction.
A precipitate is formed in some of the double displacement reaction.
Water is formed in neutralization reaction when an acid reacts with a base to produce a salt and water.
Hence, the correct answer is Option 1.
Answer:
a salt
Explanation:
Which of the following indicates that an exothermic reaction has taken place?
A. a change in color
B. release of heat and/or light energy
C. cooling of the surroundings
D. absorption of heat by the reaction ...?
The option B is correct option. Which is release of heat and/or light energy .
Explanation:According to the definition of exothermic reaction :
An exothermic reaction is a chemical reaction that releases energy by light or heat.
From definition option B (release of heat and/or light energy) indicates that an exothermic reaction has taken place.
.
Answer: Option (B) is the correct answer.
Explanation:
An exothermic reaction is defined as the chemical reaction in which there occurs release of heat.
For example, [tex]A + B \rightarrow AB + Heat[/tex]
In an exothermic reaction, energy of reactants is more than the energy of products.
Whereas an endothermic reaction is defined as a chemical reaction in which heat is absorbed by reactant molecules.
For example, [tex]A + B + Heat \rightarrow AB[/tex]
In endothermic reaction, energy of reactant molecules is less than the energy of products.
Thus, we can conclude that release of heat and/or light energy indicates that an exothermic reaction has taken place.
What is the chemical name of the compound K2SO4?
Potassium Sulfate
Explanation:Potassium sulfate is a non-flammable white crystalline salt which is soluble in water. The chemical compound is commonly used in fertilizers, providing both potassium and sulfur.
Joey and Ross designed an experiment to test the effectiveness of the newest acne cream on the market, Zit-B-Gone. Joey followed the manufacturer's directions for a total of 10 days. Each day Joey and Ross counted the number of blemishes on Joey's face and recorded the results. At the end of the 10 days, they created a line graph of their data. They concluded that Zit-B-Gone was not effective in removing blemishes. Janice, a representative from the company, sees their results and tells them, "Zit-B-Gone works just fine...Look at how your blemishes decreased in the first few days." How should Joey and Ross respond to Janice?
A) They should ignore the data after day 5 and agree with Janice.
B) They should restart the whole experiment and throw out all of the current data.
C) They should say that Zit B Gone was not effective because the blemishes reappeared.
D) They should agree with Janice and realize that they have looked at the data wrongly.
The correct answer is C
Joe and Ross should respond to Janice by saying that Zit B Gone was not effective because the blemishes reappeared.As the blemishes reappeared there could possibly be an error in their results.
What is an error?Errors in chemical analysis result when there is a difference between observed value and the true value.If the magnitude of errors is large , it results in decrease in accuracy, reproducibility, and precision.
There are three types of errors:1) random error 2) systematic error 3) human error.The cause of random errors are difficult to quantify while the human errors can be minimized by taking a range of readings to reduce the error.
Errors while measuring boiling point may be human errors while noting down the boiling temperature or instrumental or systematic error if there is a fault in the thermometer.
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How is the hydrosphere and the geosphere alike
Only the _____ word in an organism's complete scientific name has its first letter capitalized
Answer:
it's first I don't know why that dude has such a low rating I got it correct from his/her answer.
Explanation:
The pH of a solution is 1.20. What is the [H3O+] for the solution?
1.58 × 10−2 M
6.31 × 10−2 M
1.58 × 101 M
6.31 × 101 M
Answer:
[H₃O⁺] = 6.31 x 10⁻² mol·L⁻¹
Explanation:
pH = -log[H₃O⁺], so [tex][\text{H}_{3}\text{O}^{+}] = 10^{- \text{pH}} \text{ mol/L}[/tex]
[tex][\text{H}_{3}\text{O}^{+}] = 10^{-1.20}\text{ mol/L} = 6.31 \times 10^{-2}\text{ mol/L}[/tex]
Answer:
[tex]6.31*10^{-2}[/tex]
Explanation:
Hello! To calculate the pH we have the following formula:
ph = -log [H3O +]
In this case we have the pH value so the formula is
[H3O +] = [tex]10^{-pH}[/tex]
[H3O +] = [tex]10^{-1.2}[/tex]
We use the inverse of the log
[H3O +] = [tex]6.31*10^{-2}[/tex]
So the correct answer is [tex]6.31*10^{-2}[/tex]
A basketball weigh more after it was inflated with air then when it was deflated how does this show that gas is matter
The fact that a basketball weighs more when inflated compared to when it's deflated is indicative that gas (air, in this case) is matter because it contributes to the mass and occupies space within the basketball.
Explanation:The phenomenon that a basketball weighs more after it is inflated with gas (in this case, air) compared to when it is deflated, shows us that gases have mass and occupy space, hence they are considered matter. The principle of matter states that it has mass and occupies space. When you inflate the basketball, you are filling it with air, which is a gas, and increases the total mass of the basketball. Thus, making the basketball heavier than it was when it was deflated. This change in weight clearly demonstrates that gas is indeed matter as it contributes to the overall mass of the basketball.
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Based on their locations in the periodic table, which best compares the properties of the metalloids arsenic and antimony?
Answer:
Arsenic has a more nonmetallic behavior than antimony because arsenic's atoms have fewer electron shells.
Explanation: