Answer: A
Explanation: A model has to be identical to the thing it represents in every way, or people may think something is different than it actually is, because they see it in the model. The answer to the question is A.
How many molecules of water are produced when 8.93 * 1023 molecules of oxygen are reacted with
excess hydrogen gas in the reaction below?
2H2 + O2 → 2H2O
Answer: 1.79 x 10^24 molecules H2O
Explanation:
Use the following conversion factors to convert from molecules of oxygen to molecules of water: 1 mole O2/ 6.02 x 10^23 molecules O2, 2 mole H2O/ 1 mole O2, 6.02 x 10^23 molecules H2O/ 1 moles H2O
How much limestone (in kg) is required to completely neutralize a 4.5 billion liter lake with a pH of 5.3
Answer:
1105.7kg of limestone must be added
Explanation:
A solution is neutralized when pH = 7.0. That is [H+] = 1x10⁻⁷M.
The initial [H+] is 10^-5.3 = 5.01x10⁻⁶M.
That means we need to neutralize:
5.01x10⁻⁶M - 1x10⁻⁷M = 4.91x10⁻⁶M
The moles of H+ in 4.5 billion liters = 4.5x10⁹L are:
4.91x10⁻⁶M * (4.5x10⁹L) = 22095 moles of H+
That reacts with limestone (CaCO3), as follows:
2H+ + CaCO3 → H2O + CO2 + Ca²⁺
Moles of limestone needed to neutralize the lake are:
22095 moles of H⁺ * (1 mole Limestone / 2 moles H⁺) = 11047.5 moles of limestone.
Molar mass of limestone is 100.09g/mol. Mass of limestone we need to add are:
11047.5 moles of limestone * (100.09g / mol) = 1.106x10⁶g of limestone. In kg:
1.106x10⁶g of limestone * (1kg / 1000g) =
1105.7kg of limestone must be added
how can you determaine that a coin is not pure silver if you know the mass and volume of the coin plz hurry
Answer:
easy
Explanation:
Divide the mass by the volume to calculate its density. If its density isn't the same as an equal amount of pure silver, the coin has some other metal in it.
A characteristic used to determine a type of mineral is
please help fast
Answer:
Cleavage and Fracture
Explanation:
Cleavage and Fractures are both characteristics used to determine a type of mineral, along with hardness, luster, color, streak, specific gravity, and tenacity, all of which not included in the answers.
The atoms in a sample are close together but can slide past one another. As the atoms lose energy, they move slower. The atoms become locked in place because of attractive forces between them.
Which change of state is taking place?
gas to solid
gas to liquid
liquid to solid
solid to liquid
Answer:
liquid to solid
Explanation:
liquid atoms are closer together but can slide past one then it starts to lose energy and locks in which in that case turns intl a solid.
Hopefully that helped
The scenario described in the question suggests a change from a liquid state to a solid state, known as solidification or freezing. When a liquid is cooled, the energy of the molecules decreases and they begin to move more slowly.
What happens when the temperature approaches zero ?As the temperature approaches the freezing point, the attractive forces between the molecules begin to overcome their thermal energy, causing the molecules to arrange themselves in a more organized and compact structure. Eventually, the molecules become locked in place, forming a solid.
The degree to which a liquid can be supercooled before solidifying depends on factors such as the specific properties of the liquid, the rate of cooling, and the presence of impurities.
In some cases, supercooling can occur where a liquid is cooled below its normal freezing point without solidifying. However, even in these cases, the liquid will eventually solidify if it is disturbed or seeded with a small crystal of the solid phase.
Therefore, Solidification is an important process in many industries, such as metalworking and manufacturing of plastics and ceramics. Understanding the factors that influence solidification can help improve the quality and properties of these materials.
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AgCL would be least soulble at 25 degrees Celcius in ___ A. pure water B. 0.1 M HNO3 C. 0.1 M CaCl2 D. 0.1 M HCL E. It is equally soluble in all of these substances.
Answer: The answer is C. 0.1MCaCl2
Explanation:
We have AgCl whose least solubility is to be determined at 25degree Celsius
so upon looking at the options given we observe C 0.1MCaCl2 and D 0.1MHCl both have chlorine ions present and we know that here common ion effect will happen that causes decreases the solubility of the AgCl here
but when Calcium chloride dissociates it gives 2 moles of chlorine ions
[tex]CaCl2[/tex]→[tex]Ca^+2 + 2Cl^-[/tex]
so chlorine ion will be present in more amount [tex]2*0.1\\[/tex]=[tex]0.2[/tex] as compared to the chlorine produced by HCl
[tex]HCl[/tex]→[tex]H^+ +Cl^-[/tex] only 1 mole of chlorine is produced.
Hence AgCl will be least soluble in 0.1M CaCl2
Which of these is measured during a scientific investigation
Answer:
What ae the options?
Explanation:
6. Matter is anything that occupies______
and has_____
Answer:
Any thing that takes up space and has mass
Explanation:
Answer:
1.mass 2.space
Your welcome
The following reaction is a single replacement reaction. What happens to the oxidation number of the elements in this reaction? Show proof. Li(s) + CuCl2(s)=LiCl(s) + Cu(s)
Answer:
1. The oxidation number of Li changes from 0 to +1
2. The oxidation number of Cu changes from +2 to 0.
3. The oxidation number of Cl remains the same in each compound.
Explanation:the equation for the reaction is given below:
Li(s) + CuCl2(s) —> LiCl(s) + Cu(s)
Next, we shall determine the oxidation number of each element in the reaction.
NOTE: 1. Oxidation number of chlorine (Cl) is always –1 in any compound because it is a ground 7 element.
Now, we shall determine the change in oxidation number of each element. This is illustrated below:
1. For Li:
Li = 0 (ground state)
LiCl = 0
Cl = –1
Li + (–1) = 0
Li – 1 = 0
Collect like terms:
Li = 0 + 1
Li = +1
The oxidation number of Li changes from 0 to +1
2. For Cu:
CuCl2 = 0
Cu + 2Cl = 0
Cl = –1
Cu + 2(–1) = 0
Cu – 2 = 0
Collect like terms
Cu = 0 + 2
Cu = +2
Cu = 0 (ground state)
The oxidation number of Cu changes from +2 to 0.
3. For Cl:
The oxidation number of Cl remains the same in each compound.
Summary:
1. The oxidation number of Li changes from 0 to +1
2. The oxidation number of Cu changes from +2 to 0.
3. The oxidation number of Cl remains the same in each compound
the reaction A->B is second order in A and the rate constant is 0.039L/mol s. if it took 23 sec for the concentration of A to decrease to 0.30 M, what was the starting concentration of A
Answer:
0.41 M
Explanation:
A -> B
rate constant (k) = 0.039L/mol s
t = 23
Final concentration, [A] = 0.30M
Initial concentration, [A]o = x
1 / [A] = kt + 1 / [A]o
1 / [A]o = 1 / [A] - kt
1 / [A]o = 1 / 0.30 - 0.039 (23)
1 / [A] = 3.33 - 0.897 = 2.433
[A] = 0.41 M
HELP, ONLY ONE ANSWER!
Which is a possible consequence of decreasing air quality resulting from global warming?
A.) drying out of fertile lands
B.) flooding of low-lying coastal areas
C.) melting of glaciers and polar ice caps
D.) decrease in population due to health threats
Answer:
Its d
Explanation:
Got it correct
Answer:
d
Explanation:
did the test
classify the following mixtures as to its type: (solution/colloid/suspension)
a. condensed milk-
b. paint-
c. flour and water-
d. brine (salty water)-
Answer:
Colloid = Condensed milk, Paint
Solution = brine
Suspension = flour and water
Explanation:
Colloid:
Colloid is a mixture in which smaller particles of one substance are evenly distributed throughout into another substance.
These particles are smaller than the particles present in suspension but larger than the particles present in solution.
Condensed milk is example of colloid.
Paint is also example of colloid in which pigment particles dispersed.
Solution:
In solution one or more substances are dissolved into the another substance. The substance which is being dissolved is called solute while the substance which has tendency to dissolve the other substance is called solvent. It is homogenous mixture.
Salty water is example of solution in which salt are solute dissolved in solvent which is water.
Suspension:
In suspension solute particles are not dissolved they are dispersed into bulk of solvent. The solute particles are larger then the particles present in colloid.
flour and water is the example of suspension.
Do not look up the answer on google, because I know exactly what the answer is. If you answer right will give thanks and brainliest
Answer:
THE ANSWER IS CORRECT!!
Strontium is in Group 2 or the periodic table. Which number of electrons must be gained or lost for strontium to form a complete valence shell?
A. 2 gained
B.2 lost
C. 6 gained
D. 6 lost
IM MARKING BRAINIEST!!!!
A 50.0 mL sample of 0.0152 M Na2SO4(aq)is added to 50.0 mL 0.0125 M Ca(NO3)2(aq). What percentage of the Ca2 remains unprecipitated
Answer:
38.4%
Explanation:
Step 1 Obtain the concentration of Ca^2+ and SO4^2-
[Ca^2+] = 0.05 L (0.0125 mol/L) (1/0.1 L) = 6.25 * 10^-3 M
[SO4^2-] = 0.05 L (0.0152mol/L) (1/0.1L) = 7.60 * 10^-3 M
Step 2 Obtain the concentration of [SO4^2-] left
Ca^2+(aq) + SO4^2-(aq)------> CaSO4(s)
initial 6.25 * 10^-3 M 7.60 * 10^-3 M
final 0 1.35 * 10^-3 M
Step 3 Determine the amount of Ca^2+ left from the common ion problem
CaSO4(s) --------> Ca^2+(aq) + SO4^2-(aq)
initial 0 1.35 * 10^-3 M
equilibrium x (1.35 * 10^-3 + x) M
But Ksp of CaSO4 = 9.1 * 10^-6
Ksp = [Ca^2+] [SO4^2-]
9.1 * 10^-6= [x] [1.35 * 10^-3 + x]
9.1 * 10^-6= 1.35 * 10^-3 x + x^2
Rearranging:
x^2 + 1.35 * 10^-3 x + 9.1 * 10^-6 = 0
solving the quadratic yields x = 2.4 * 10^-3
Step 4 Calculate the amount of Ca^2+ remaining;
% Ca^2+ remaining = 2.4 * 10^-3/ 6.25 * 10^-3 M * 100
% Ca^2+ remaining = 38.4%
1. How do scientists know how hot the
core is?
A. Thermometers
Seismic waves
C. Oil wells
D. Measure the electromagnetic
spectrum
A.THERMOMETERS SEISMIC WAVES
2. Glucose, C6H12O6, along with O2 is a product that is produced from photosynthesis of plants. How many grams of carbon are in 16.55 g of glucose
Answer:
6.62 g of carbon.
Explanation:
We'll begin by calculating the molar mass of C6H12O6. This is illustrated below:
Molar mass of C6H12O6 = (12×6) + (12×1) + (16×6)
= 72 + 12 + 96
= 180 g/mol
Next, we shall determine the mass of carbon (C) in 1 mole (i.e 180 g) of C6H12O6. This is illustrated:
Mass of C in C6H12O6 = 6C = 12×6
Mass of C in C6H12O6 = 72 g
Thus, 180 g of glucose contains 72 g of carbon.
Finally, we shall determine the mass of carbon in 16.55 g of glucose. This can be obtained as follow:
180 g of glucose contains 72 g of carbon.
Therefore, 16.55 g of glucose will contain = (16.55 × 72)/180 = 6.62 g of carbon.
Thus, 16.55 g of glucose contains 6.62 g of carbon.
Liquid octane reacts with gaseous oxygen gas to produce gaseous carbon dioxide and gaseous water . If of carbon dioxide is produced from the reaction of of octane and of oxygen gas, calculate the percent yield of carbon dioxide. Be sure your answer has the correct number of significant digits in it.
The question is incomplete; the complete question is;
Liquid octane CH3CH26CH3 reacts with gaseous oxygen gas O2 to produce gaseous carbon dioxide CO2 and gaseous water H2O. If 2.80g of carbon dioxide is produced from the reaction of 3.4g of octane and 5.9g of oxygen gas, calculate the percent yield of carbon dioxide. Be sure your answer has the correct number of significant digits in it.
Answer:
55%
Explanation:
The balanced equation is:
C8H18(g) + 25/2O2(g) ----------> 8CO2(g) + 9H2O(g)
The limiting reactant IS first determined. This is the reactant that yields the least amount of product.
3.4 g octane / 114 g/mol = 0.030 mol octane
From the reaction equation;
1 mole of octane yields 8 moles of CO2
0.030 mol octane yields 0.030 * 8/1 = 0.24 moles of CO2
5.9 g O2 / 32 g/mol = 0.18 mol O2
25/2 moles of O2 yields 8 moles of CO2
0.18 moles of O2 yields 8 * 0.18/25/2 = 0.1152 moles of CO2
Oxygen is the limiting reactant.
Number of moles of carbon dioxide produced (actual yield) = 2.8 g/44g/mol = 0.0636 moles of CO2
% yield = actual yield/ theoretical yield * 100
% yield = 0.0636/0.1152 * 100= 55%
Which of the following statements is true about Sir Isaac Newton?
A. He realized that the Moon orbits Earth.
B. He made a connection between the mass of objects and the distance between them.
C. He discovered gravity when an apple fell on his head.
D. He found that gravity was the strongest force.
Answer:
B. he made a connection between the mass of objects and the distance between themThe true statement about Sir Isaac Newton is that he made a connection between the mass of objects and the distance between them. Hence option B is correct.
What is mass?Mass is defined as a dimensionless number used to describe the mass of a particle or item. Gravity and inertia, which are the two main forces influencing how objects move in space, make mass crucial. A substance's mass, expressed in kilograms (kg), can be used to estimate its matter content.
Every item in the universe is attracted to one another by a force that is directly proportional to the product of the masses of the objects and inversely proportional to the distance between them, according to Newton's law of universal gravitation.
Thus, the true statement about Sir Isaac Newton is that he made a connection between the mass of objects and the distance between them. Hence option B is correct.
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Proper way water molecules form hydrogen bonds
Explanation:
Water molecules form hydrogen bonding when the oxygen of one water molecule combines with the hydrogen of another molecule.
Hydrogen bonding is an electrostatic attraction between the hydrogen atom of one molecule and the electronegative atom of a neighboring molecule.
This bond is made possible by the electronegativity difference between oxygen and hydrogen for water molecules. The intermolecular forces is responsible for the physical and chemical properties of water.What are the BCNOs in relation to the periodic table?
Answer:
Binding properties
Explanation:
g what is ΔG for the reaction at 298K, when the partial pressure of C2H4 is 0.275 atm, the partial pressure of H2O is 0.350 atm, and the partial pressure of C2H5OH is 0.100 atm?
Answer:
[tex]\Delta G=8015\frac{J}{mol}[/tex]
Explanation:
Hello.
In this case, for the following chemical reaction in gaseous phase:
[tex]C_2H_4+H_2O\rightleftharpoons C_2H_5OH[/tex]
We can write the equilibrium expression as:
[tex]Kp=\frac{p_{C_2H_5OH}}{p_{H_2O}*p_{C_2H_4}}[/tex]
it means that given the pressures, we can compute Kp as shown below:
[tex]Kp=\frac{0.100atm}{0.275atm*0.350atm}=1.04[/tex]
Next, we compute Kc at 298 K:
[tex]Kc=\frac{Kp}{(RT)^{1-1-1}}=\frac{Kp}{(RT)^{-1}}[/tex]
Whereas 1-1-1 comes from the stoichiometric coefficients of products minus reactants. Therefore, Kc is:
[tex]Kc=\frac{1.04}{(0.08206*298)^{-1}}=25.4[/tex]
Thus, the Gibbs free energy for this reaction is:
[tex]\Delta G=RTln(kC)=8.314\frac{J}{mol*K}*298K*ln(25.4)\\ \\\Delta G=8015\frac{J}{mol}[/tex]
Best regards!
How many possible stereoisomers are there of panthenol, an organic compound found in L'Oreal shampoo
Answer:
2
Explanation:
Panthenol (or provitamin B5) is an active ingredient used as a moisturizer, in particular, to treat sensitive and dry skin. It also goes into the hair care formulation to nourish dry hair. All the benefits of this precursor of vitamin B5.
It has moisturizing, anti-inflammatory, regenerating, and healing properties. Panthenol also strengthens the hydrolipidic film, improves the elasticity of the skin, and promotes cell renewal in the event of injuries: this is why it is also used in the event of injuries or sunburn.
Thus, from the image below, the structure of Panthenol is being shown and the number of possible stereoisomers is being outlined as well.
Why does the liquid in a thermometer go down when it is placed in ice water?
The cold of the ice makes the liquid condense?
The surrounding air is too hot?
The density is decreasing with the temperature?
The liquid is attracted to the cold?
Answer: A) Cold ice makes the liquid condense
On the flip side, warm temperatures make the liquid expand. Since there is only one direction to go, the liquid expands upward until it reaches a certain marker on the thermometer, to indicate the temperature.
How is mechanical weathering different from chemical weathering?
a
Chemical weathering happens over a much shorter time frame than mechanical weathering.
b
Chemical weathering happens in the tropics; mechanical weathering occurs in temperate climates.
c
Chemical weathering happens in mountains; mechanical weathering happens on flat surfaces.
d
Chemical weathering changes the chemical makeup of materials; mechanical weathering doesn't.
Answer:
c
Explanation:
A 125-mL sample of gas at 105 kPa has its volume reduced to 75.0 mL. What is the new pressure?
Answer:
87.0
Explanation:
Hopes this helps
Chromium (III) oxide reacts with hydrogen sulfide gas to form chromium (III) sulfide and water.a)writedown the balanced equation for the reaction.b)To produce 421 g of Cr2S3, how many moles of Cr2O3are required
Answer:
The balanced chemical equation for the reaction can be computed as:
[tex]\mathbf{Cr_2O_3_{(s)}+ 3H_2S_{(g)} \to Cr_2S_3_{(s)} + 3H_2O_{(l)}}[/tex]
2.103 moles of [tex]Cr_2O_3_{(s)}[/tex] is being required.
Explanation:
The balanced chemical equation for the reaction can be computed as:
[tex]\mathbf{Cr_2O_3_{(s)}+ 3H_2S_{(g)} \to Cr_2S_3_{(s)} + 3H_2O_{(l)}}[/tex]
Recall that numbers of moles = [tex]\dfrac{mass}{molar \ mass}[/tex]
∴
number of moles of Cr2S3 = [tex]\dfrac{421}{200.19}[/tex]
number of moles of Cr2S3 = 2.103 moles
It obvious from the balanced equation that:
1 mole of [tex]Cr_2S_3_{(s)}[/tex] requires 1 mole of [tex]Cr_2O_3_{(s)}[/tex]
Thus; 2.103 moles of [tex]Cr_2S_3_{(s)}[/tex] = 2.103 × (1/1) moles of [tex]Cr_2O_3_{(s)}[/tex]
= 2.103 moles of [tex]Cr_2O_3_{(s)}[/tex]
A flask contains 15.5mL of hydrogen that was collected under a pressure of
22.5 kPa. What pressure would have been required for the volume of the gas
to have been 9.00mL, assuming the same temperature?*
the chemical formula of tetraphosphorus hexasulfide
Answer:
Molecular Formula
P4S6
Molecular Weight
316.3 g/mol
P[tex]_4[/tex]S[tex]_6[/tex] is the chemical formula of tetraphosphorus hexasulfide. These can only include one typographic line containing symbols.
A chemical formula is a way to describe the chemical ratios of the atoms that make up a specific chemical compound or molecule in chemistry. Chemical element numbers, symbols, and on occasion other symbols, including parentheses, dashes, brackets, commas, and plus (+) and minus () signs, are used to represent the chemical elements. Which may also include subscripts or superscripts. Since a chemical formula inherently wordless, it cannot be considered a chemical name. A chemical formula does not equal a complete chemical structural formula, despite the fact that it may suggest certain basic chemical structures. P[tex]_4[/tex]S[tex]_6[/tex] is the chemical formula of tetraphosphorus hexasulfide.
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Students are given a sample of an unknown material. They want to perform tests to determine its identity. Which test is MOST likely to change the sample into another material?
a
dissolving it in water
b
heating it until it melts
c
heating it until it melts
d
burning it in a flame
Answer: a
. dissolving it in water
Explanation:
When the unknown material is dissolved in water, it could react with the water particles and end up producing another material. For instance an alkali metal in water could form metal oxides.
Heating the material until it melts will not change it into another material because it will still be the same material only now it will be in liquid form. The same logic applies if it is burnt in a flame.
