20 B203(s) + 12180 HF(l) = 4060 BF3(g) + 609 H20(l)
Calculate the mass percent for a solution containing 85g NaCl and 155g water.
The mass percent for a solution : 35.42%
Further explanationThe concentration of a substance can be expressed in several quantities such as moles, percent (%) weight/volume,), molarity, molality, parts per million (ppm) or mole fraction. The concentration shows the amount of solute in a unit of the amount of solvent.
[tex]\tt \%mass=\dfrac{mass~solute}{mass~solution}\times 100\%[/tex]
mass solute = 85 g
mass solution = 85 + 155 = 240 g
[tex]\tt \%mass=\dfrac{85}{240}\times 100\%=35.42\%[/tex]
Calculate ΔS∘rxn for the following reaction. The ΔS∘ for each species is shown below the reaction.
C2H2(g) + 2H2(g) → C2H6(g)
S∘(J/mol⋅K) 200.9 130.7 229.2
A) -159.0 J/K
B) -233.1 J/K
C) +233.1 J/K
D) 303.3 J/K
E) 560.8 J/K
Answer:
-233.1 J/K
Explanation:
The standard entropy change for the reaction C₂H₂(g) + 2 H₂(g) → C₂H₆(g), is B) -233.1 J/K.
Let's consider the following balanced equation.
C₂H₂(g) + 2 H₂(g) → C₂H₆(g)
Entropy is a measure of how much the energy of atoms and molecules becomes more spread out in a process. We can calculate the standard entropy change for the reaction (ΔS°rxn) using the following expression.
[tex]\Delta S \°_{rxn} = \Sigma n_p \times S_p\° - \Sigma n_r \times S_r\°[/tex]
where,
n: molesS°: standard entropy of the speciesp: productsr: reactants[tex]\Delta S \°_{rxn} = 1 mol \times S\°(C_2H_6) - 1 mol \times S\°(C_2H_2) - 2 mol \times S\°(H_2)\\\Delta S \°_{rxn} = 1 mol \times (229.2J/mol.K) - 1 mol \times (200.9J/K.mol) - 2 mol \times (130.7J/K.mol) = -233.1 J/K[/tex]
The standard entropy change for the reaction C₂H₂(g) + 2 H₂(g) → C₂H₆(g), is B) -233.1 J/K.
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Which is true about periods and groups?
O Groups are horizontal and their number tells us the number of energy levels in an atom of that
element. Periods are vertical and contain elements with similar properties.
Periods are horizontal and their number tells us the number of energy levels in an atom of that
element. Groups are vertical and contain elements with similar properties.
Answer:
Periods are horizontal and their number tells us the number of energy levels in an atom of that element.
Groups are vertical and contain elements with similar properties.
Explanation:
The periodic table systematically arranges elements over one another based on their atomic numbers.
Elements having the same number of electrons in the outermost shell of their atoms are placed over one another in vertical columns called groups or family. Hence, elements in the same group will have similar chemical properties.
Elements in the same period have the same number of electronic shell. This number corresponds to the energy level of the elements.
Identify when an object has a kinetic energy of zero joules.
Question 2 options:
A. as a pendulum swings downward.
B. when the energy has been destroyed.
C. just after a ball it leaves your hand pitching a ball.
D. when an object is no longer in motion.
Answer:
D I think
Explanation:
cuz 0 j means there is nothing moving
Answer:
D. when an object is no longer in motion.
Explanation:
a rock that originally had a mass of 1.00g of uranium_238 now only has .125g left. how old is the rock if the half life of uranium_238 is 4.5 billion years?
Answer:
no it would be 2.5 mill your welcome
Explanation:
What was the molecular geometry for SC16?
Answer:
I'm assuming this is for the SCl₆ compound and not SC₁₆? If so, the molecular geometry is octahedral.
Explanation:
There are 6 regions and zero lone pairs surrounding the central atom (S).
How many moles of magnesium chloride can be formed from 4.86 g of Mg and 21.27 g of Cl2?
Answer:
Moles of magnesium chloride can be produced are 0.2 moles
Explanation:
The reaction of Mg with Cl2 is:
Mg + Cl₂ → MgCl₂
Where 1 mole of Mg reacts per mole of Cl₂ to produce MgCl₂.
As the reaction is 1:1, we need to convert the mass of both Mg and Cl₂ to moles. The lower number of moles will determine the moles of MgCl₂ that will be produced:
Moles Mg -Molar mass: 24.3g/mol-:
4.86g * (1mol / 24.3g) = 0.2 moles Mg
Moles Cl₂ -Molar mass: 24.3g/mol-:
21.27g * (1mol / 70.9g) = 0.3 moles Cl₂
As moles of Mg < moles of Cl₂, Mg is limiting reactant and moles of magnesium chloride can be produced are 0.2 moles
A cell in the leaf of a corn plant contains more chloroplasts than a cell in the stem of a corn plant. Based on this observation, it can be inferred that, when compared to the cell in the stem, the cell in the leaf
Answer:
This question lacks options, the options are:
A). synthesizes more sugar
B). has a higher chromosome count
C). produces fewer proteins
D). uses less carbon dioxide
The answer is A
Explanation:
The chloroplast is an organelle present in the cells of photosynthetic organisms. It is the site where photosynthesis, which is the production of food (sugars) from sunlight energy, occurs.
According to this question, a cell in the leaf of a corn plant contains more chloroplasts than a cell in the stem of the same corn plant. Based on this observation, it can be inferred that the LEAF CELLS WILL SYNTHESIZE MORE SUGARS THAN THE STEM CELL because the more the chloroplast, the higher the photosynthetic rate and subsequently the higher the amount of sugar produced.
Solid calcium carbonate decomposes to produce solid calcium oxide and carbon dioxide gas. Express your answer as a chemical equation. Identify all of the phases in your answer.CaCO,(s)-CaO(s) + CO2(g)
Answer:
[tex]CaCO_3(s)\rightarrow CaO(s)+CO_2(g)[/tex]
Explanation:
Hello!
In this case, when solid calcium carbonate, CaCO3 (s), is decomposed by the action of thermal energy (heat), solid calcium oxide, CaO (s) and carbon dioxide gas, CO2 (g) are yielded via the following reaction:
[tex]CaCO_3\rightarrow CaO+CO_2[/tex]
However, since calcium carbonate is solid as well as calcium oxide and carbon dioxide is given off as a gas, we write:
[tex]CaCO_3(s)\rightarrow CaO(s)+CO_2(g)[/tex]
Which also balanced.
Best regards!
What mass of precipitate can form if 1.5 L of a saturated solution of Pb(NO3)2 is mixed with 0.765 L of a 0.205 M NaI solution?
Answer:
[tex]m_{PbI_2}=36.2gPbI_2[/tex]
Explanation:
Hello!
In this case, since the chemical reaction that takes place when Pb(NO3)2 and NaI are mixed is:
[tex]Pb(NO_3)_2(aq)+2NaI(aq)\rightarrow PbI_2(s)+2NaNO_3(aq)[/tex]
By which a solid precipitate of PbI2 is produced. In such a way, since we know the volume and molarity of NaI, we can compute the moles of NaI as shown below:
[tex]n_{NaI}=0.765L*0.205\frac{molNaI}{L}=0.157molNaI[/tex]
Next, since it is in a 2:1 mole ratio with PbI2 (molar mass = 461.01 g/mol) we compute the mass of PbI2 precipitate as shown below:
[tex]m_{PbI_2}=0.157molNaI*\frac{1molPbI_2}{2molNaI}*\frac{461.01 gPbI_2}{1molPbI_2} \\\\m_{PbI_2}=36.2gPbI_2[/tex]
Best regards!
Which best explains why an iceberg floats?
Water expands and becomes denser when it freezes.
Water contracts and becomes denser when it freezes.
Answer:
The options to this question are incomplete. The remaining two options are:
C. Water expands and becomes less dense when it freezes.
D. Water contracts and becomes less dense when it freezes.
The answer is C. Water expands and becomes less dense when it freezes.
Explanation:
Water is a chemical compound that exists in the three states of matter viz: solid as ICE, gas as vapour and liquid as WATER. However, due to the DENSITY properties of each state, ice floats on water. Ice is less dense than water.
When liquid water freezes, it's particles expands i.e increases in volume. Hence, it becomes less dense than water. This causes an iceberg to float on water because it has a lesser density compared to the liquid water caused by an expansion of its particles.
Answer:
answer is c
Explanation:
While boiling potatoes for dinner in salted water, the pot boils over and you notice that the flame on your gas burner turns to bright yellow-orange. How would you explain the appearance of a color in the previously blue flame?
Answer:
This observation can be explained under the following reasons:
High sodium contentLowered heat temperatureOrganic burnExplanation:
High sodium content from the potato fluid causes the flame to turn yellow, as indicative of the presence of sodium (flame test).
The colour change could also be attributed to the drastic lowering of the burner heat. Finally, pure organics like wood and fats burn red, a would be the case with fluids from the boiled potatoes.
I hope this explanation was helpful.
The appearance of a yellow-orange color in the previously blue flame is due to the presence of sodium ions in the salted water.
The salted water in which the potato is being boiled contains sodium ions according to the equation:
[tex]NaCl ---> Na^+ + Cl^-[/tex]
Sodium ions generally give off yellowish color when burned in flames. Thus, when the pot boiled over, ions of sodium got into the flame on the gas burner and give off their characteristic flame color.
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In this lab, you will do experiments to identify types of changes. Using the question format you learned (shown above), write an investigative question that you can answer by doing these experiments. Lab question: How can you distinguish a physical change from a chemical change?
Answer:
a physical change does not change the composition (what it's made of) as a chemical change would.
Physical changes are differentiated from the chemical changes by means of the state of the substance which is obtained after the change.
What are physical changes ?Physical changes are defined as changes which affect only the form of a substance but not it's chemical composition. They are used to separate mixtures in to chemical components but cannot be used to separate compounds to simpler compounds.
Physical changes are always reversible using physical means and involve a change in the physical properties.Examples of physical changes include melting,boiling , change in texture, size,color,volume and density.Magnetism, crystallization, formation of alloys are all reversible and hence physical changes.
They involve only rearrangement of atoms and are often characterized to be changes which are reversible.
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2.83 kJ are added to a sample of water at 100°C and it completely vaporizes. What is the
mass of the water?
general formula
Answer:
general formula: Q=mHv, 2.83=m(2260), 2260/1000=2.26 , 2.83/2.26=1.25 kJ
Explanation:
Conner conducts the following experiment. He places a bell in a vacuum jar. During his first trial, he leaves the bell outside the jar. He sees the bell vibrating and he hears the bell ringing. During his second trial, he removes the air from the vacuum jar. He sees the bell vibrating but he does not hear the abell ringing. What does this experiment tell the student about waves?
A.Light waves are electromagnetic waves and sound waves are mechanical waves.
B.Light waves are mechanical waves and sound waves are electromagnetic waves.
C.Both light waves and sound waves need a medium to travel through.
D.Neither light nor sound waves need a medium to travel through.
Answer:
A. Light waves are electromagnetic waves and sound waves are mechanical waves.
Explanation:
The experiment is clear proof that light waves are electromagnetic waves and that sound waves are mechanical waves.
Electromagnetic waves are waves that do not require a material medium for their propagation. Although, with material medium they can also be propagated. This is why in both set up, the bell still vibrates. Mechanical waves are dependent on the material in the medium. They cannot be propagated in vacuum. There is no matter present in vacuum to help transmit the sound waves.What does the reduction potential chart tell you about two elements?
A. Where they are located on the periodic table
B. Which is more likely to be reduced
C. Which forms a positive ion
D. Which one is a metal
Answer:
which is more likely to be reduced
Explanation:
Answer:
B
Explanation:
The air particles in the jar become smaller.
Which term describes the process of water moving from plant leaves to the atmosphere? Air pressure Humidity Transpiration Density
Explanation:
transpiration good luck
Answer:
Transpiration
Explanation:
I took a quiz on the water cycle and this was the correct answer. if I am wrong then I am sorry but I'm pretty sure this is correct.
What is the name of the product that forms when sodium hydroxide reacts with propanoic acid?
Answer:
Propionic acid reacts with NaOH(aq) to form sodium propionate and water.
Laszlo is running a column to separate a carboxylic acid and an alkyne. He accidentally uses acetone instead of hexane as his first eluent. What happens? A. The first fraction contains only carboxylic acid and the second fraction contains only alkyne. B. The first fraction contains both the carboxylic acid and the alkyne. C. The fractions are empty because both compounds remain on the column. D. The first fraction contains only alkyne and the second fraction contains only carboxylic acid. E. The first fraction contains only carboxylic acid and the alkyne remains on the column F. The first fraction contains only alkyne and the carboxylic acid remains on the column.
Answer:
B. The first fraction contains both the carboxylic acid and the alkyne.
Explanation:
Carboxylic acids dissolve in both polar and non-polar organic solvents hence they can dissolve in acetone along with the alkyne.
The correct sequence of adding eluting solvents is reversed, would have been the addition of hexane first in order to elute the alkyne selectively. The acetone may now be subsequently added to elute the carboxylic acid.
If this order the carboxylic acid and alkyne are eluted simultaneously.
According to the equation, 2Al(s) + 6H2O(l) + 2KOH(aq) to make 2K[Al(OH)4](aq) + 3H2(g). How many grams of hydrogen gas would be formed in the reaction of 1.15 grams of Al and excess KOH?
Answer:
0.06457g of H₂
Explanation:
2Al(s) + 6H₂O(l) + 2KOH(aq) → 2K[Al(OH)₄](aq) + 3H₂(g)
Based on the equation 2 moles of Al produce 3 moles of hydrogen.
First, we need to convert mass of Al to moles and then with the chemical equation find moles and mass of hydrogen:
Moles Al (Molar mass: 26.982g/mol):
1.15g Al * (1mol / 26.982g) = 0.04262 moles Al
Moles H₂:
0.04262 moles Al * (3 moles H₂ / 2 mol Al) = 0.06393 moles H₂
Mass hydrogen (Molar mass: 1.01g/mol):
0.06393 moles H₂ * (1.01g/mol) =
0.06457g of H₂Write the dissolution reaction for ammonium phosphate in water. Be sure to specify the state of each reactant and product.
Answer:
The equation showing the dissolving of solid ammonium phosphate in water is: (NH4)3 PO4 (s) → 3NH4 +1 (aq) + PO4 -3 (aq).
Explanation:
List five acids and five bases we come across in our day to day activities under the correct heading.
acids -
citric acid- citrus fruits
lactic acid -milk
amino acids- protein
tannic acid -tea
malic acid -apple
Bases-
baking soda (Nahco3)
How many moles of oxygen, are needed to react with excess propane, C3H8, to produce 15.0 moles of water?
Answer:
1 mole of C3H8 reacts with __five__ moles of O2 to produce __three__ moles of CO2 and of H2O.
Explanation:
Hope This Helps
An element with the electron configuration: [noble gas] ns2 (n - 1)d10 np3 has how many_____________ valence electrons.
a. 2
b. 15
c. 3
d. 10
e. 5
Answer:
The correct option is e. 5
Explanation:
An element with the electron configuration [noble gas] ns² (n - 1)d¹⁰ np³ belongs to the nitrogen group element - group 15 - in a period higher than 2. The element could be As, Sb or Bi. For example, arsenic (As) has the electron configuration [Ne] 4s² 3d¹⁰ 4p³.
The valence electrons are those in the highest energy level, in a s or p sublevel. For the elements with the general electron configuration [noble gas] ns² (n - 1)d¹⁰ np³ has 5 valence electrons: 2 electrons in a s sublevel and 3 electrons in a p sublevel. The electrons in the d orbital are in a lowest energy level (n-1).
Therefore, the correct option is e. 5.
NEED HELP ASAP PLEASE HELP
Answer:
I think it's A not D or C maybe B probably A
When a solution is allowed to crystallize slowly, impurities are excluded from the growing crystal structure because: A. The molecules in the crystal lattice are cooler than the solvent and impurities would have too high a melting point to join the lattice.B. The molecules in the crystal lattice are in equilibrium with the molecules in solution and molecules that don't fit well into the lattice (impurities) are likely to return to the solution.C. Impurities could never join the lattice because they are always liquid at room temperature.D. During slow crystallization, impurities are prevented from joining the crystal structure because of their ionic strength.
Answer:
B
Explanation:
4. Chemical formula, mg (Cl0₃)2
a) calculate the number of moles for 3.24g, Mg (Cl03)2
b) calculate the molarity of mg (Cl03)2 if all of it were dissolved in
5.08 L distilled water.
Answer:
0.017mole
0.0033M
Explanation:
Given parameters:
Formula of the compound:
Mg(ClO₃)₂
Mass of the sample = 3.24g
Unknown:
Number of moles of the sample = ?
Molarity = ?
Solution:
The number of moles of any substance is given as:
Number of moles = [tex]\frac{mass}{volume}[/tex]
Molar mass of Mg(ClO₃)₂ = 24 + 2[35.5 + 3(16)] = 191g/mol
Number of moles = [tex]\frac{3.24}{191}[/tex] = 0.017mole
Molarity is the number of moles of a solute in a solution:
Molarity = [tex]\frac{number of moles }{volume}[/tex]
Volume given = 5.08L
Molarity = [tex]\frac{0.017}{5.08}[/tex] = 0.0033M
During a tug of war competition neither team was able to gain an advantage which of the following explains the force is this situation
You add 10.00 mL of 0.200 M NaOH to 50.00 mL of pure water, and to this mixture you then add 5.00 mL of 0.100 HCl. What will be the pH of the resulting solution?
Answer:
Need ko point salamat mamaya ko yan sagutin d jowklang
28.00mL