Answer:
Physical change
Explanation:
A physical change is one in which no new substance is formed and can be reversed using physical methods.
When we mix the salt and water, we have merely carried out a physical change. No new substance was formed. To recover the salt, we simply heat the solution to dryness.
Hence, this is an example of a physical change.
The graph models the amount remaining, in milligrams, of a radioactive substance as a function of time, in years. Explain the meaning of the point (3100) shown on the graph. Answer in complete sentences.
Answer:
Where is the grahppppp?!!!!
The __________ stage of Kohlberg’s postconventional level focuses on making judgments based on what best protects individuals.
A.
marketplace morality
B.
social contract
C.
law and order
D.
good boy/good girl
Answer:
the answer is B- social contract
Explanation:
the person above me is correct
What intermolecular force or bond is primarily responsible for the solubility of CH3OH in water?
A. Covalent bonding
B. Ionic bonding
C. Ion-dipole force
D. Hydrogen bonding
E. Dipole-dipole force
Answer:
D
Explanation:
Hydrogen Bond is one of the many different types of bonds there are. It is a primarily electrostatic force of attraction between a hydrogen atom that is covalently bounded to another electronegative atom or group. The group it bonds with mostly are elements of the second-row elements in the periodic table, like nitrogen oxygen or even fluorine. Hydrogen bonds have the capabilities to be either intermolecular or intramolecular. This often depends on the nature and type of thees atoms donating, and even that of the atoms receiving.
5. After undergoing 4 half-lifes what % of a 150 g sample of I-L-L will remain?
Answer:
6.25%
Explanation:
Given data:
Total sample = 150 g
Percentage remain after 4 half life = ?
Solution:
at time zero 150 g
At first half life = 150 g/2 = 75 g
At 2nd half life = 75 g/ 2 = 37.5 g
At 3rd half life = 37.5 g/2 = 18.75 g
At 3rd half life = 18.75 g/2 = 9.375 g
Percentage remain after 4 half lives.
9.375 g / 150 g × 100
0.0625 × 100
6.25%
What is the mole fraction of NaOH in
an aqueous solution that contains
15.0% NaOH (weight/weight %)?
Molar Mass
NaOH: 39.998 g/mol
H2O: 18.016 g/mol
Answer:
The more fraction NaoH is 39.998g/mol
Answer:
.0735 is correct
Explanation:
Lithium and nitrogen react in a combination reaction to produce lithium nitride:
6Li(s) + N_2(g) → 2Li_3N(s)
In a particular experiment, 1 00 g samples of each reagent are reacted. The theoretical yield of Iithium nitride is __________.
a. 5.0
b. 0.84
c. 1.01
d. 1.67
e. 2.50
Answer:
Option D. 1.67 g
Explanation:
The balanced equation for the reaction is given below:
6Li (s) + N₂ (g) → 2Li₃N (s)
Next, we shall determine the masses of Li and N₂ that reacted and the mass of
Li₃N produced from the balanced equation. This can be obtained as follow:
Molar mass of Li = 7 g/mol
Mass of Li from the balanced equation = 6 × 7 = 42 g
Molar mass of N₂ = 14 × 2 = 28 g/mol
Mass of N₂ from the balanced equation = 1 × 28 = 28 g
Molar mass of Li₃N = (7×3) + 14 = 21 + 14 = 35 g/mol
Mass of Li₃N from the balanced equation = 2 × 35 = 70 g
SUMMARY:
From the balanced equation above,
42 g of Li reacted with 28 g of N₂ to produce 70 g of Li₃N.
Next, we shall determine the limiting reactant. This can be obtained as illustrated below:
From the balanced equation above,
42 g of Li reacted with 28 g of N₂.
Therefore, 1 g of Li will react with =
(1 × 28)/42 = 0.67 g of N₂
From the calculation made above, we can see that only 0.67 g of N₂ out of 1 g given is required to react completely with 1 g of Li.
Therefore, Li is the limiting reactant and N₂ is the excess reactant.
Finally, we shall determine the theoretical yield of Iithium nitride, Li₃N.
The theoretical yield of Iithium nitride, Li₃N, can be obtained by using the limiting reactant as illustrated below:
From the balanced equation above,
42 g of Li reacted to produce 70 g of Li₃N.
Therefore, 1 g of Li will react to produce = (1 × 70)/42 = 1.67 g of Li₃N.
Thus, the theoretical yield of Iithium nitride, Li₃N is 1.67 g.
what the formula of bisethylenediphosphinecobalt(lll)-meu-imido-meu-
hydroxobisbipyridinecobalt(lll) ion.
How many mL of 0.105 M aqueous NaOH solution are required to neutralize 40.0 mL of 0.210 M aqueous H2SO4 solution?
H 2SO 4 + 2 NaOH ---> Na 2SO 4 + 2 H 2O
Answer:
160 mL
Explanation:
Given data:
Molarity of NaOH = 0.105 M
Volume of H₂SO₄ = 40.0 mL (40.0/1000 = 0.04 L)
Molarity of H₂SO₄ = 0.210 M
Volume of NaOH required = ?
Solution:
Number of moles of of H₂SO₄:
Molarity = number of moles / volume in L
0.210 M = number of moles / 0.04 L
Number of moles = 0.210 mol/L × 0.04 L
Number of moles = 0.0084 mol
now we will compare the moles of H₂SO₄ with NaOH.
H₂SO₄ : NaOH
1 : 2
0.0084 : 2/1×0.0084 = 0.0168 mol
Volume of NaoH:
Molarity = number of moles / volume in L
0.105 M = 0.0168 mol / Volume in L
Volume in L = 0.0168 mol / 0.105 M
Volume in L = 0.16 L
Volume in mL:
0.16 L × 1000 mL/ 1L
160 mL
The volume of the NaOH solution required for the reaction is 160 mL
The balanced equation for the reaction is given below:
H₂SO₄ + 2NaOH —> Na₂SO₄ + 2H₂O
From the balanced equation above,
The mole ratio of the acid, H₂SO₄ (nA) = 1The mole ratio of the base, NaOH (nB) = 2Finally, we shall determine the volume of the base, NaOH required for the reaction.
Molarity of the base, NaOH (Mb) = 0.105 MVolume of the acid, H₂SO₄ (Va) = 40 mL Molarity of the acid, H₂SO₄ (Ma) = 0.210 M Volume of the base, NaOH (Vb) =?MaVa / MbVb = nA/nB
(0.21 × 40) / (0.105 × Vb) = 1 / 2
8.4 / (0.105 × Vb) = 1 / 2
Cross multiply
0.105 × Vb = 8.4 × 2
0.105 × Vb = 16.8
Divide both side by 0.105
Vb = 16.8 / 0.105
Vb = 160 mL
Thus, the volume of the base, NaOH required for the reaction is 160 mL
Learn more about stoichiometry: https://brainly.com/question/21182105
What is the tightly stretched membrane that forms the entrance to the middle ear called?
Answer:
I'm so happy to help you with this question!! The answer is tympanic.
Explanation:
The middle ear is separated from the outer ear by the eardrum, or tympanic membrane, a thin piece of tissue stretched tight across the ear canal. Sounds hit the eardrum, making it move.
I really hope this helps you!! :)
What is true about uranium atoms
Answer:
They have the same number of protons. Scientists are working wit a liquid that is made of only one type of atom.
GOOD LESSONS ♡
Assume that a film includes repeated scenes showing the trademark Voom on the sports shoes of its attractive adolescent protagonists. Althoughthe film is successful among young audiences, no increase occurs in the sale of Voom shoes. Which of the following hypotheses about this outcome is the most plausible on the basis of the studies cited?
A) Audiences feel uncomfortable because Voom is an unfamiliar brand.
B) Most members of the audience already own a pair of Voom shoes.
C) Audiences are worried by the social implications of these scenes.
D) Audiences are too engrossed in the story to notice the shoes.
Answer: D
Explanation: Even if the audiance did not have a pair of shoes felt uncomfortable or worried not a lot of people would have noticed. If anyone noticed it would only be about 5% of people so that is how I came to the conclision of D.
The accepted value is 29.35. Which correctly describes this student's experimental data?
Answer:
- Both accurate and precise.
Explanation:
The experimental data is characterized as the data that is generated through a specific test or measurement with the purpose of analysis or evaluation. As per the question, the minuteness of the given data(29.27, 29.32, and 29. 27)most aptly describes that the experimental data collected by the student possesses 'accuracy and precision' apt and specific. It would yield the most worthy and reliable conclusion.
According to the activity series, which one of the following reactions will occur?
SrF2 + Br2 --->
KOH + Mg --->
FeCl3 + I2 --->
Co3N2 + Ba --->
I will award brainliest!!!!
Answer:
i think
SrF2 + Br2 --->
dont count me on it
Explanation:
balanced
Liquid boils faster at mountain region than in terai region. why?
Answer:
are you silly your question is opposite silly
Answer:
beacuse this reason has lower atmospheric pressure due to a thinner blanket of air above. ... As atmospheric pressure decreases, liquid boils at lower temperatures. due to which it takes less time than terai region
Displacement can be observed when
you
A. boil water on the stove.
B. place an apple on a scale.
C. measure the height of a plant.
D. jump into a pool and see the water splash.
be
Answer:
D) Water splashing
Explanation:
Displacement is about moving something from its original place. In A, B, and C nothing is being moved. This makes D the only answer!
Please I need an answer
Uncontrolled energy:
A. Produces order
B. Causes destruction
C. Can make things
D. Can do useful work
Answer:
B: causees destrution
Explanation:
its right trust me
What os the formula for hexaboron tetrabromide
Answer:
B6Br4
Explanation:
Chemical formula gives a representation of the number of atoms that each element in a compound or molecule. In this question which is asking to give the formula of hexaboron tetrabromide, the hexa means 6 while the tetra means four.
Since the number of atoms of each element is written as a prefix before the main element, this means that the chemical formula of hexaboron tetrabromide will be B6Br4.
If I tripled the number molecules of Ag2 SO4 from 1 to 3 how would this effect this compound ?
Answer:
AgCl(s)
dissolution
⇌
precipitation Ag+(aq)+Cl−(aq)
Explanation:
dynamic; some of the solid AgCl continues to dissolve, but at the same time, Ag+ and Cl– ions in the solution combine to produce an equal amount of the solid. At equilibrium, the opposing processes have equal rates.
PLEASE HELP Which of the answers below would be a correct chemical symbol of an element?
HG
hg
Hg
hG
Answer:
Hg
Explanation:
Hg is a correct chemical symbol of an element. Therefore, The correct option is option C among all the given options.
What is element?The quantity of protons an element has defines it. An element's atoms all contain the same amount of protons, but its electron and neutron counts might vary. Ions are produced by altering the electron to proton ratio, whereas isotopes are produced by altering the neutron count.
A material that cannot be destroyed chemically is referred to as a chemical element. Although chemical processes cannot modify an atom, nuclear reactions can create new elements. Hg is a correct chemical symbol of an element. A material that is not further decomposed either by chemical reaction is known as a chemical element.
Therefore, Hg is a correct chemical symbol of an element. The correct option is option C among all the given options.
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Which of the following elements has the strongest ionization energy: Mg or Cl? Define ionization
energy and explain why based on the attractive force between protons and electrons.
Answer:
Cl
Explanation:
The element Cl will have the strongest ionization energy from the given choices. Most non-metals have higher ionization energy compared to metals.
Ionization energy is the energy required to remove the most loosely held electron from the gaseous phase of an atom.
As you go from left to right on the periodic table, it increases progressiveFrom top to bottom, the ionization energy reduces significantly. The attractive force between the protons in the nucleus and the electrons plays a very important role. In metals, they have very large atomic radius, the attractive force on the outer electrons is very weak. This is not the case in non-metalsWhat property of water enables ice wedging to break rock?
A.
Water is a polar molecule.
B.
Water contains oxygen.
C.
Frozen water takes up more space than liquid water.
D.
Each water molecule contains 18 electrons.
Answer:
c
Explanation:
hope I helped
hope im corrext
Ice wedging can be defined as the property of frozen water to take more space than liquid water. Thus, option C is correct.
The ice has been the solid state of water. The liquid molecules bond together for the resulting solid molecule.
Ice wedging can be defined as the mechanical weathering of the rock by the effect of ice. The rocks have consisted of cracks that accumulated water in them.
With the decrease in the temperature, the water has been expanded and has been converted to ice. The expansion of water in the cracks results in the breaking of the rocks.
Thus, ice wedging can be defined as the property of frozen water to take more space than liquid water. Thus, option C is correct.
For more information about ice wedging, refer to the link:
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Which of the following will decrease the percentage ionization of 1.0 M acetic acid, CH3CO2H(aq)?
a. Chlorinating the CH3 group
b. Diluting the solution
c. Adding concentrated HCL(aq)
d. Adding a drop of basic indicator
Answer: C. Adding concentrated HCL(aq)
Explanation:
HCl is an efficient acid that will increase the quantity of H+ in the solution and thus reduce the ionizing percentage of Ch3CO2H. The amount of ionization of the latter would be reduced by the addition of strong acid to a solution of weak acid.
What makes a compound
polar?
Answer:
Polar molecules occur when two atoms do not share electrons equally in a covalent bond. ... If the electronegativity difference between the atoms is greater than 2.0, the bond is ionic. Ionic compounds are extremely polar molecules.
Explanation:
Scientists us ________waves to study the characteristics of Earth Layers_______ cannot travel through liquid, so the ________must be liquid.
Answer:
1)seismic 2) S-waves 3) outer core
Answer:the other comment is right
Explanation:
An imaginary planet was just discovered that has a similar environment to our planet Earth. All the chemistry is similar except for the values of bond energies. Use the planet's given bond energies to calculate the enthalpy of reaction for the combustion of 1 mole of pentane.
Enter a number to O decimal places in kJ/mol
Bond Energy (kJ/mol)
H-H 585
C-H 257
H-O 478
C-C 370
C C 779
CC 992
0-0 490
C-0 251
C-0 740
Answer: [tex]\Delta H_{rxn}=-4652[/tex] kJ/mol
Explanation: In a reaction, a bond of a molecule can break or rearrange itself. When it happens, it absorb or release energy.
Bond Energy is the energy necessary to break or to make a particular bond, producing gaseous fragments at atmospheric temperature. This type of energy can be used to show how stable a compound is or how easy a bond can break.
Enthalpy of Reaction is the energy absorption or release at a constant temperature resulting from a chemical reaction.
To calculate the Enthalpy using bond energy, you have:
1) Write the balanced equation with all the all the reactants and products in gaseous form:
[tex]C_{5}H_{12}_{(g)}+8O_{2}_{(g)}[/tex] ⇒ [tex]5CO_{2}_{(g)}+6H_{2}O_{(g)}[/tex]
2) Count each bond of each molecule from both sides, including double or triple bonding, if they exists:
Reactants:
[tex]C_{5}H_{12}[/tex] : 12 C-H
4 C-C
O₂ : 1 O=O
Products:
CO₂ : 2 C=O
H₂O : 2 H-O
3) From the balanced reaction, we there are 8 moles of oxygen gas, 5 moles of carbon dioxide and 6 moles of water, which has to be included when adding each side.
[tex]\Sigma H_{reactants}=[/tex] 12.257 + 4.370 + 8.490 = 8484
[tex]\Sigma H_{products}=[/tex] 5.2.740 + 6.2.478 = 13136
4) Calculate Enthalpy of Reaction by:
[tex]\Delta H_{rxn}= \Sigma H_{reactants}-\Sigma H_{products}[/tex]
[tex]\Delta H_{rxn}=8484-13136[/tex]
[tex]\Delta H_{rxn}=-4652[/tex]
The enthalpy of reaction for the combustion of 1 mole of pentane on a just discovered imaginary planet is an exothermic process of magnitude [tex]\Delta H_{rxn}=[/tex] - 4652kJ/mol
Using the planet's given bond energies to calculate the enthalpy of reaction, the combustion of 1 mole of pentane is -4652 kJ.
The balanced chemical reaction for the combustion of pentane is well represented as:
[tex]\mathbf{C_5H_{12}+8O_2 \to 5CO_2+6H_2O}[/tex]
From the above reaction, the bonds broken are 12 Carbon-Hydrogen bonds, 4 Carbon-Carbon bonds, and 8 oxygen-oxygen bonds.
Similarly, the bonds formed are 10 Carbon-Oxygen bonds and 12 Oxygen-hydrogen bonds.
Hence, the energy absorbed when bonds are broken are:
= 12(C-H) + 4(C-C) + 8(O-O)
= 12(257 kJ) + 4(370 kJ) + 8(490 kJ)
= 3084 kJ + 1480 kJ+ 3920 kJ
= 8484 kJ
Also, the energy released as a result of the formation of bond is:
= 10 (C=O) + 12 (O-H)
= 10 (740 kJ) + 12 (478 kJ)
= 7400 kJ + 5736 kJ
= 13136 kJ
From above, we can notice that the energy released during the formation of bonds is greater than the energy absorbed while breaking bonds.
Thus, the enthalpy of the combustion reaction is the difference in energy.
i.e.
The enthalpy of the combustion reaction = 8484 kJ - 13136 kJ
= -4652 kJ
Therefore, we can conclude that the enthalpy of reaction from the combustion of 1 mole of pentane is -4652 kJ. The negative sign indicates that more energy is released compared to the amount of energy absorbed.
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How would you put this word equation into a balanced chemical equation: Aluminum nitrate reacts with potassium sulfate to produce aluminum sulfate and potassium nitrate.
Answer:
2Al(NO_{3} )_{3} + 3K_{2}SO_{4} ----> Al_{2}(SO_{4})_{3} + 6KNO_{3}
Explanation:
[tex]2Al(NO_{3} )_{3} + 3K_{2}SO_{4} ----> Al_{2}(SO_{4})_{3} + 6KNO_{3}[/tex]
Samples of limestone, granite, quartz, and stalactite are exposed to acidic groundwater. All other conditions being equal, which rock would weather most quickly?
A.
the limestone, because the acidic groundwater would dissolve the rock's calcite
B.
the granite, because the acidic groundwater would oxidize the rock's iron
C.
the quartz, because it would absorb the water, increasing the rock's density and placing added pressure on its molecules
D.
the stalactite, because the water would loosen the bonds that hold its molecules togethe
Answer:
Both A and B
Explanation:
A.
the limestone, because the acidic groundwater would dissolve the rock's calcite
B.
the granite, because the acidic groundwater would oxidize the rock's iron
In contact freezing _____ are used for _____ freezing of foods
immersion -- cryogenic liquids
refrigerants -- immersion
immersion -- refrigerants
cryogenic -- immersion
Answer:
In contact freezing refrigerants are used for immersion freezing foods.
Explanation:
3) What is the mass of a sample consisting of 1.00 X 1022 formula units of MgSO.?(
number of moles = 1.00 X 10^22 ÷ 6.022 × 10^23
= 0.0166 moles
mass = number of moles × molar mass
= 0.0166 × 120.37 = 2.00 g
The pKa of a weak acid was determined by measuring the pH of a solution containing the weak acid at 0.40 M and its conjugate base at 0.60 M. The measured pH was 7.8. What is the pKa of the weak acid
Answer:
7.62
Explanation:
Given that :
pH = 7.8
Conjugate base in solution = 0.6 M
Weak Acid in solution = 0.4 M
Recall :
pH = pKa + log(conjugate base / acid)
Hence,
PKa = pH - log(conjugate base / acid)
pKa = 7.8 - log(0.6 / 0.4)
pKa = 7.8 - log(1.5)
pKa = 7.8 - 0.1760912
pKa = 7.6239088
Hence, pKa = 7.62 (2 decimal places)