Answer:
c. Ralph's classmate observing Daphnia in water at 30oC, 32oC and 34oC
Explanation:
When we talk about replication, we actually mean, repetition of a scientific procedure carried out by another scientist and obtaining the same results as he/she previously did.
Replication is carried out under identical conditions as the first scientist did. If Ralph's classmate wants to replicate Ralph's work, then identical temperature conditions of 30oC, 32oC and 34oC must be used, hence the answer above.
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:
Oxygen is a __________ and nitrogen is a __________. metalloid, metalloid nonmetal, metal nonmetal, nonmetal nonmetal, metalloid metal, metalloid
Answer:
"nonmetal, nonmetal"
Explanation:
Oxygen is a non metal and Nitrogen is a non metal. It is 8th element of the periodic table. It is located in period 2 and group 16.
Nitrogen lies at the group 15 of the periodic table. Its atomic no is 7. Its valency is 2.
Hence, the correct option is (c) "nonmetal, nonmetal".
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!
ILL GIVE YOU A CROWN
Which farming method would mostly likely prevent soil erosion?
A.
contour plowing, to slow down water flow
B.
maximum tillage, to continually rotate topsoil
C.
planting one type of crop, to eliminate plant variety
D.
adding clay to the soil, to increase drainage
Answer:
A
Explanation:
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
triarsenic pentasulfide what is the formula?
Answer:
As2S5
Explanation:
I hope this is the answer.
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]
which of the following can contaminate an aquifer?
A. All of these
B. landfills
C. agricultural regions
D. Animal feces
E. gas stations
Answer:
I think it is c
Explanation:
I'm sorry if I'm wrong had to look up aquifers
aquifer-a body of permeable rock which can contain or transmit groundwater
landfills, agricultural regions, and gas stations can contaminate an aquifer.
Aquifer:The aquifer is a layer of liquid rock beneath the earth. Underground water is contaminated by excavation and quarrying, increased fertilizer use, and septic tank leakage.
However, the construction of France does not contaminate subsurface water. Applied in various fields, ground-level structures with steps due to water storage are in rural places, it's used to store water.As a result, landfills, agricultural areas, and petrol stations contaminate an aquifer.Therefore, the correct choices are "Option B, Option C, and Option E".
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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.
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
If the decomposition of a sample of KClO3 produces 3.29 g of O2 , what was the mass (g) of the original sample?
Answer: Thus 8.41 g was the mass of the original sample
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} O_2=\frac{3.29g}{32g/mol}=0.103moles[/tex]
[tex]2KClO_3\rightarrow 2KCl+3O_2[/tex]
According to stoichiometry :
As 3 moles of [tex]O_2[/tex] are produced by = 2 moles of [tex]KClO_3[/tex]
Thus 0.103 moles of [tex]O_2[/tex] are produced by =[tex]\frac{2}{3}\times 0.103=0.0687moles[/tex] of [tex]KClO_3[/tex]
Mass of [tex]KClO_3=moles\times {\text {Molar mass}}=0.0687moles\times 122.5g/mol=8.41g[/tex]
Thus 8.41 g was the mass of the original sample.
8.41 grams is the mass of original sample of KClO₃.
How we calculate mass from moles?Mass of any substance will be calculated from the moles as:
n = W/M, where
W = given or required mass
M = molar mass
Given chemical reaction is:
2KClO₃ → 2KCl + 3O₂
Given mass of O₂ = 3.29g
Moles of O₂ = 3.29g/16g/mole = 0.103 moles
From the stoichiometry of reaction, it is claer that:
3 moles of O₂ = produced by 2 moles of KClO₃
0.103 moles of O₂ = produced by 2/3×0.103 = 0.0687 moles of KClO₃
Now mass of KClO₃ = 0.0687 × 122.5g/mol = 8.41g
Hence, 8.41g is the mass of KClO₃.
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What are the types of ions and how are they formed?
Answer:
-Cations: They are formed by an atom losing an electron or electrons.
-Anions: They are formed by an atom gaining an electron or electrons.
what is the noble gas configuration for zirconium?
A. [Xe] 5s2 4d1
B. [Xe] 4d1
C. [Kr] 4d1
D. [Kr] 5s2 4d1
Answer:
[Kr] 4d² 5s²
Explanation:
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-metalsPLEASE 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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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
why seals and sea lions would not be considered fish.
Answer:
The word 'pinniped' means 'fin foot', as the four legs of seals, sea-lions and walrus have developed into flippers to better suit their life in the water. They are not fish! Even though a great part of their life is spent in the sea, pinnipeds are warm blooded air-breathing mammals known as marine mammals.
Explanation:
Sea lions (left) are brown, bark loudly, "walk" on land using their large flippers and have visible ear flaps. Seals have small flippers, wriggle on their bellies on land, and lack visible ear flaps. ... Both seals and sea lions, together with the walrus, are pinnipeds, which means "fin footed" in Latin.
To solve this we must be knowing each and every concept related to sea lions. Therefore, due to above given reason, seals and sea lions are not considered fish.
What is sea lions?Sea lions are curious creatures with sleek bodies that are playful as well as acrobatic in behavior. The species that can be found in aquariums and zoos the most frequently are California sea lions, who enthrall visitors with their antics. This captivating animal possesses a variety of extraordinary traits that are just amazing. Learn more about this sea lion by reading on.
Scaled fish have a cold blooded constitution. Their bodies are streamlined, and they breathe underwater. Fur covers seals and sea lions. They are warm blooded and breath air.
Therefore, due to above given reason, seals and sea lions are not considered fish.
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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
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The _____ time it takes to completely _____ food, the _____ the food will deteriorate.
less -- unfreeze -- more
more -- hydrate -- less
less -- freeze -- less
The answer is C.less -- freeze -- less
How many grams of sucrose must be dissolved in 250 ml to prepare the 0.15 mol / L solution?
Answer:
How could you prepare 250 mL of 0.20M NaCl using only a solution of 1.0M NaCl and water? To prepare a 250 mL 0.20 M NaCl solution, I would place 50 mL of the 1.0 stock solution to a 250 mL volumetric flask and then add 200 mL of water. A bottle of the antiseptic hydrogen peroxide (H2O2) is labeled 3.0% (v/v).
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:
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.
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
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%
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)
Which reaction is capable of breaking polypeptides into their component amino acids?
a. hydrogenation (adding hydrogen)
b. hydrolysis (adding water)
c. dehydrogenation (removing hydrogen)
d. dehydration (removing water)
Answer: B. Hydrolysis (adding water)
Explanation:
When peptide bonds join two or more amino acids together, this is refered to as a peptide. A polypeptide simply means several amino acids. We should also note that proteins contains polypeptides.
The reaction that is capable of breaking polypeptides into their component amino acids is hydrolysis. This simply means a chemical process whereby a water molecule is being added to a particular substance.
I
Graduated cylinder reading
Triple beam balance reading,
Work for the molar mass.
Work for the number of moles.
Convert graduated cylinder reading to L
Work for molarity.
Answer:
lhigygygigy
Explanation:
hyfgutfytifytftyfjgfhjfv
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.
For the following reaction,use the identity of the alkyl halide and nucleophile to determine which substitution mechanism occurs.Then determine which solvent affords the faster reaction.
A) SN1,H2O
B) SN1,DMF
C) SN2,H2O
D) SN2,DMF
Answer:
a) SN1/H2O
b) SN1/CH3OH
c)SN2/DMF
d)SN2/HMPA
Explanation:
The reactions are shown in the image attached.
Let me restate the basic facts about SN1 and SN2 reaction mechanisms. SN1 reaction occurs by unimolecular mechanism and involves a carbocation, a poor nucleophile and a polar protic solvent.
An SN2 reaction is a bimolecular synchronous reaction that passes through a single transition state. It requires a good nucleophile and a polar aprotic solvent.
For reaction a and b, we observe that the alkyl halide is tertiary hence the reaction occurs by SN1 mechanism in the presence of a polar protic solvent.
Reactions c and d involves primary and secondary alkyl halides respectively and good nucleophiles. The best solvents to be used are polar aprotic solvents and the reaction follows SN2 mechanism.
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.