The student uses the spectrophotometer to determine the absorbance the standard solutions at the wavelength of 510nm and constructs the standard curve. The molar concentration of solution is 2 M.
The mass of the CoCl₂ = 2.60 g
The molar mass = 130 g/mol
The moles = mass / molar mass
The moles = 2.60 / 130
= 0.02 mol
The number of the moles is 0.02 mol.
The molarity expression is given as :
The molarity = moles / volume
= 0.02 / 0.100
= 2 M
Thus, the molarity or The molar concentration of the solution is 2 M.
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calculating a molar heat of reaction from formation enthalpies
The sum of the standard enthalpies of formation of the products minus the sum of the standard enthalpies of formation of the reactants.
Define molar heat?
Molar heat capacity is defined as the amount of heat required to raise 1 mole of a substance by 1 degree Kelvin. Molar heat capacity is very similar to specific heat capacity but measures per mole instead of per gram of substance.The specific heat capacity of an object is the amount of energy that is required to raise the temperature of one gram of substance on one degree Celsius. The molar heat capacity is the amount of energy that is required to increase the temperature of one mole of substance by one degree Celsius.The molar heat of fusion of a substance is the heat absorbed by one mole of that substance as it is converted from a solid to a liquid. Since fusion and solidification of a given substance are the exact opposite proce20-Osses, the numerical value of the molarheat of fusion is the same.To learn more about enthalpies refers to:
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Is lithium and oxygen an ionic bond?
A lithium-oxygen ionic connection is created. Since lithium belongs to group 1A, each of its atoms possesses one valence electron. Lithium's Lewis valence electron structure is seen here.
Since oxygen belongs to group 6A, each of its atoms contains six valence electrons.
Lewis valence dot diagrams are models that only display the valence electrons, therefore it's vital to keep that in mind. In the lower energy levels, which are those closest to the nucleus, there are frequently more electrons that are not involved in bonding and are not seen on an electron dot diagram. If the atom loses all the valence electrons in that valence shell, exposing the level below it, the inner electrons can be seen.
Let's examine how to build Lewis valence electron dot structures of a single element before you begin sketching electron dot formulae of ionic compounds.
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What are the two things that the Hertzsprung-Russell diagram use to classified stars
The Hertzsprung-Russell diagram (HR diagram) uses two things to classify stars: their luminosity and their temperature.
Luminosity refers to the amount of energy a star emits per unit of time, while temperature refers to the surface temperature of a star, which can be determined by the star's color.
The HR diagram plots stars on a graph with luminosity on the y-axis and temperature (or color) on the x-axis. This allows scientists to study the different evolutionary stages of stars, and how their properties change over time.
The HR diagram is a powerful tool for understanding the life cycles of stars and the different types of stars that exist in the universe. It provides insight into the physical properties of stars, such as their temperatures, luminosities, and masses, and how these properties change over time.
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Of the following types of bonds or interactions between atoms, which is the WEAKEST? van der Waals forces, ionic bond, hydrogen bond, covalent bond
Van der Waals forces are the types of bonds or interactions between atoms.
Molecules/atoms can stick to each other. But much more weakly than a bond. Covalent bond strength: 50-200 kJ/mole Intermolecular force: 1-12 kJ/mole
But these weak interactions control many critical properties: boiling and melting points, vapor pressures viscosities, etc.
Molecules that have permanent dipoles are attracted to each other.
– The positive end of one is attracted to the negative end of the other, and vice versa.
– These forces are only important when the molecules are close to each other.
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how many people are in 3 moles of people?
Answer:
1.8066 x [tex]10^{24}[/tex] people
Explanation:
One mole of any substance has 6.022 x [tex]10^{23}[/tex] number of particles in it.
Using the ratio method:
moles : people
1 : 6.022 x [tex]10^{23}[/tex]
3 : X
X = (3 x 6.022 x [tex]10^{23}[/tex])
X = 1.8066 x [tex]10^{24}[/tex] people
Lime obtained from limestone is an important ingredient in the manufacture of cement. Would the Cayuga Lake Basin be a good or poor location for a cement-making plant?
Answer:
good location
Explanation:
What type of attractive force is the arrow pointing at in the molecule
The type of attractive force that the arrow is known to be pointing at in the molecule is option D. intramolecular force
What is intramolecular force about?The attracting or repellent interactions between atoms within a molecule are known as intramolecular forces. These forces keep the atoms of the molecule together. They comprise covalent, ionic, and metallic chemical linkages, among others.
Therefore, These bonds develop as a result of electron sharing or transfer between atoms. These intramolecular bonds, which are the forces that hold the atoms in the molecule together, are likely indicated by the arrow in the molecule.
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True or False
Quantum mechanics tells us the exact location of an electron
Answer:
False
Explanation:
It is impossibke to know the exact location of an electron.
How many ions are produced from a 14.3 g sample of calcium nitrate
There are 1.57 * 10^23 ions in the compound calcium nitrate.
What is the number of ions that is produced?We know that ions are species that are positively or negatively charged. We have to note that when we have the compound in this case calcium nitrate, we have to look up the number of ions that we have in it.
Calcium nitrate has one nitrate ion and two calcium ions which makes a total of three ions in the compound. We would then have;
Number of moles = mass/molar mass
= 14.3 g/164 g/mol
= 0.087 moles
Then the number of ions is;
3 * 0.087 * 6.02 * 10^23
=1.57 * 10^23 ions
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Calcium nitrate is composed of one calcium ion (Ca2+) and two nitrate ions (NO3-). 14.3g of calcium nitrate produces 3 ions.
How to calculate ions produced?To determine how many ions are produced from a 14.3 g sample of calcium nitrate, we need to know the molar mass of the compound and use the molar mass to convert the given mass of 14.3 g to moles.
The molar mass of calcium nitrate is 164.09 g/mol. To convert 14.3 g of calcium nitrate to moles, we divide the mass by the molar mass:
moles = 14.3 g / 164.09 g/mol = 0.087 mol
Since calcium nitrate is composed of one calcium ion and two nitrate ions, the number of ions produced by 0.087 moles of calcium nitrate is:
ions = (1 Ca2+) + (2 NO3-) = 3 ions
Therefore, 0.087 mol of calcium nitrate produces 3 ions.
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What’s the kinetic theory
The kinetic theory states that the forces between molecules and the energy that they possess.
What is kinetic theory ?The kinetic theory of matter helps to understand why matter exist in different stages i.e., solid, liquid and gases, and how matter can convert from one stage to another.
The assumption of kinetic theory is that the measurable characteristics of gases, liquids, and solids reflect the mixed actions of countless numbers of atoms and molecules.
Thus, The kinetic theory states that the forces between molecules and the energy that they possess.
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Does iron react with O2?
Yes, Iron reacts with O2 to give an iron oxide.
When iron comes in contact with oxygen in presence of water it gives ferric oxide, Also known as rust is formed.
The balanced chemical reaction of above is given as follows,
4Fe + 3O2 + x. H2O → 2Fe2O3.xH2O.
A redox commerce between oxygen and iron in a water-rich terrain, similar as largely sticky air, results in the conformation of rust. The rusting of iron is characterised by the conformation of a subcaste of a red, short substance that readily breaks into greasepaint. The rusting process can be stopped or braked down with a fleece of oil painting. A high- quality makeup will also help to decelerate down rusting by keeping humidity from getting to the essence.
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A student described two properties of a substance as shown. Properties of Substance Property Description C A known mass of the substance gives off heat when it is burned. D A substance can be stretched out to become a long wire. Which of the following is true about the two properties described in the table? (5 points) Both are physical properties. Both are chemical properties. C is a chemical property and D is a physical property. C is a physical property and D is a chemical property.
The change in size is a physical property and and the heat evolution by burning is a chemical property. Hence, option c is correct.
What are physical properties ?Physical properties of a substance involves, change in state, size or shape. They does not involve formation of a new compound and thus does nit undergo breaking or making of chemical bonds.
A chemical change involves the breaking or making of chemical bonds results in the formation of a new product. The change in size of a material by stretching it is a physical change.
Burning a material involves breaking of bonds and the formation of ash and other side products. Hence, option c is correct. C is a chemical property and D is a physical property.
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alcoholic fermentation converts glucose (c6h12o6) into ethanol (c2h5oh) and carbon dioxide (co2). what mass of carbon dioxide can be formed from the alcoholic fermentation of 23.4 g of glucose
The mass of carbon dioxide can be formed from the alcoholic fermentation of 23.4 g of glucose is 4.68 g
Fermentation is the term for the process of digesting glucose when there is no oxygen present.
We must balance the compound's atoms and examine them before we can answer the question.
The glucose has the following molar mass:
C₆H₁₂O₆ = (12x6) + (1x12)+ (6x 16) = 180 g/mol
Then we can write the balance reaction
C₆H₁₂O₆(aq) ⇒ 2C₂H₅OH(l) + 2CO₂(g)
The mole ratio of glucose to ethanol after balancing the equation is 1:2.
We should find moles of glucose
moles glucose = mass/ mass molar
Moles glucose = 2.34 g/ 180 g/ mole
Moles glucose = 0.013 moles
We know that 1 moles of glucose produce 2 moles of carbon dioxide so, with unitary method we can determine the moles of carbon dioxide.
Moles of CO₂ = 2/1 x moles glucose
Moles of CO₂ = 2/1 x 0.013 moles = 0.026 moles
the we can calculate the mass of CO₂
Mass CO₂= moles x mass molar
Mass CO₂ = 0.026 moles x 180 g/ moles
Mass CO₂ = 4.68 g
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How many atoms are in same plane in CH4?
The planes with the most atoms should have three hydrogen atoms as well as two hydrogen and one carbon atom.
Tetrahedral structure describes CH4. The plane that has three hydrogen atoms, two hydrogen atoms, and a carbon atom would therefore have the most atoms in it. Four planes are similar to the sides of a tetrahedron and satisfy the first requirement. Additionally, the latter criterion is met by six planes going through the tetrahedron's center and its edges. There are so a total of 10 aircraft.
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a positive ion forms when an atom loses one or more electrons in order to attain a configuration.
a. true
b. false
A positive ion forms when an atom loses one or more electrons in order to attain a configuration is a. true.
When an atom looses the electrons it forms the positively charged ion. This is because the atom is left with the less negatively charged electrons to balance positive charged. The positively charged ions are called as the cations. The example of the positively charged ion is given below :
The compound NaCl, when the Na loses 1 electron to attain the configuration and it becomes the positively charged ion as Na⁺. Thus when an atom loses one or more electrons it becomes positive ion.
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Electronegativity is tendency of an atom to attract a shared pair of towards itself.AelectronsBprotonsCneutrons
Electronegativity is tendency of an atom to attract a shared pair of electrons towards itself., i.e., option A is the correct choice.
Electronegativity is a degree of an atom's cap potential to draw shared electrons to itself. On the periodic table, electronegativity commonly will increase as you flow from left to proper throughout a length and reduces as you flow down a group. It determines how the shared electrons are disbursed among the 2 atoms in a bond. The extra strongly an atom draws the electrons in its bonds, the bigger its electronegativity. The higher the value of the electronegativity, the more strongly that element attracts the shared electrons.
Thus, the correct option is A i.e., electrons.
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What is the relative formula mass of CH4?
The relative mass of methane is 16.043. This is the ratio of the mass of molecule to the mass unit.
The Relative molecular mass is the ratio of the mass of a molecule to the unified atomic mass unit or the mass of a formula unit of the compound relative to the mass taken as exactly 12. There are 4 steps to calculating the relative molecular mass of a molecule or compound given its chemical formula. Use the chemical formula to determine how many atoms of each element are present in the compound. Write a mathematical expression to calculate the total mass of all the elements in the compound. Use the Periodic Table to find the relative atomic mass of each element. Substitute the values for the relative atomic mass (atomic weight) of each element into the equation. Then we find the relative mass.
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A sample of seawater contains 78. 0 grams of nacl in 2,025 ml of solution. If the molar mass of nacl is 58. 443 g/mol, what is the molarity of this sample?.
A sample of seawater contains 78. 0 grams of NaCl in 2,025 ml of solution. If the molar mass of NaCl is 58. 443 g/mol, the molarity of this sample is 0.65 M.
Given that :
The mass of the NaCl = 78 g
The molar mass of the NaCl = 58.443 g/mol
The number of the moles = mass / molar mass
The number of the moles = 78 / 58.443
= 1.33 mol
The molarity = moles / volume in L
= 1.33 / 2.025
= 0.65 M
Thus, the molarity of the NaCl sample with the 2.025 L is 0.65 M.
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Anhydrous copper sulphate can be used in a test for water. What two things will happen when water is added to anhydrous copper sulphate?
When water is added to anhydrous copper sulfate, two things will happen that is, Hydration and Formation of a blue color.
What is Anhydrous copper sulphate?
Anhydrous copper sulphate is a white crystalline compound used as an oxidizing agent and as a catalyst in organic chemistry. It is also used as a fungicide, herbicide, and insecticide in horticultural applications. Copper sulphate is a salt composed of copper and sulphuric acid. It is highly water-soluble and has a distinct blue-green color when dissolved in water. When anhydrous, it is a white powder. Anhydrous copper sulphate can be produced by heating the hydrated form of the salt above 250°C.
When water is added to anhydrous copper sulphate, two things will happen. Firstly, the anhydrous copper sulphate will dissolve in the water, forming a blue-colored solution. This indicates that the water is indeed present. Secondly, the anhydrous (without water) copper sulfate will absorb water and become hydrated, forming copper sulfate pentahydrate (CuSO4 * 5H2O).
Therefore, when water is added to anhydrous copper sulphate Hydration and Formation of a blue color will occur.
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How can we predict the structure of the isotopes and the most common ionic state for any given element?
An element's isotopic structure and most common ionic states can be predicted using its atomic number, electron configuration, and number of protons and neutrons in its nucleus.
Which atomic number is it?The number of electric charges in the nucleus of a chemical element is referred to as its atomic number.
This is the same as the number of protons found in the nucleus of each element's atom for normal atomic nuclei. Common chemical elements can be identified uniquely using atomic numbers.
The number of protons in an atom's nucleus or the number of electrons in an electrically neutral atom are the same as its atomic number. The number of protons is the atomic number.
The number of protons in a nucleus is commonly referred to as an atomic number. The element's identity is determined by the number of protons.
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It takes the average high school swimmer 5 minutes and 30 seconds to swim 500 yards. How fast is an average swimmer moving in feet per second. Round your answer to 3 significant figures and express your answer in decimal form
4.55 feet/second rounded to 3 significant figures is 4.56 feet/second, fast is an average swimmer moving in feet per second.
To calculate the speed of the swimmer in feet per second, we need to know how many feet are in 500 yards and then divide that by the time it takes the swimmer to swim 500 yards.
1 yard = 3 feet
So, 500 yards = 500 * 3 = 1500 feet
Time = 5 minutes and 30 seconds = 5 * 60 + 30 = 330 seconds
To find the speed in feet per second, we divide the distance by the time:
Speed = 1500 feet / 330 seconds = 4.55 feet/second
To round the answer to 3 significant figures, we look at the fourth digit after the decimal point, which is 5. Since it is greater than or equal to 5, we will round up the third digit after the decimal point from 5 to 6.
So, the speed of an average high school swimmer is 4.55 feet/second rounded to 3 significant figures is 4.56 feet/second.
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What is the ringed area outside of the nucleus of an atom (in this case with three rings) called?
Answer: The orbit of the electrons
What is the dominant
intermolecular force
found between hydrogen
iodide molecules?
Hydrogen
Ion-dipole
Dispersion
Dipole-dipole
Answer:
Dipole-Dipole
Explanation:
Iodine is a halogen is that is partially negative while the hydrogen is partially positive. So it will create this dipole attraction among the molecules.
Not hydrogen bonding since the only molecules that can participate are N, O, F.
Not Ion-Dipole since that is usually for ionic compounds.
Not disperion forces since it's the weakest of the forces.
Explain why the solution of ethanoic acid has a higher pH than the solution of
hydrochloric acid.
Answer:
ethanoic acid is weak acid
ph (4 5 6)
hydrochloric acid is strong acid
ph(1 2 3)
for acid the more higher pH,the weak acid
How do you find electrons in ch4?
The total number of the electrons are in the formation of the CH₄ molecule are 8 electrons.
The CH₄ is called as the methane. The methane includes the four hydrogen atoms and the one carbon atom.
The electronic configuration of C = 1s² 2s² 2p²
The electronic configuration of H = 1s²
The methane molecule contains the four bond. The electrons involved in the formation of the each bond are two electrons.
The number of the electrons = 2 × 4
The number of the electrons = 8 electrons
Thus, the total valence electrons in the methane CH₄ are 8 electrons.
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a major component of gasoline is octane . when liquid octane is burned in air it reacts with oxygen gas to produce carbon dioxide gas and water vapor. calculate the moles of oxygen needed to produce of water.
The moles of oxygen needed to produce of water is 0.5 moles of oxygen. To calculate the moles of oxygen needed to produce a certain amount of water, we need to know the chemical equation for the combustion of octane (C8H18) with oxygen gas (O2).
The equation is: 8CO2 + 9H2O = C8H18 + 12.5O2
As we can see from the equation, for every 1 mole of octane that is burned, 12.5 moles of oxygen are needed to produce the 9 moles of water vapor. Therefore, if we want to calculate the moles of oxygen needed to produce a certain number of moles of water, we can simply divide the number of moles of water by the ratio of water to oxygen in the equation (9:12.5).
For example, if we want to know how many moles of oxygen are needed to produce 2 moles of water, we would divide 2 by the ratio of water to oxygen, which is 2/(9/12.5) = 0.5 moles of oxygen.
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Look at the equations for the two reactions:
Reaction 1 CuCO₃(s) + 2HCl(aq) ⇒ CuCl₂(aq) + H₂O(l) + CO₂(g)
Reaction 2 CuO(s) + 2HCl(aq) ⇒ CuCl₂(aq) + H₂O(l)
Calculate the percentage atom economy for Reaction 2.
The atom economy of reaction 2 is 57.8%.
What is the atom economy?We have to note that the atom economy would have to do with the atoms that are utilized and the atoms that are not utilized in the process. We have to consider the left and the right hand sides of the reaction.
Mass of the desired product = 63.5 + 2(35.5) = 134.5
Mass of the reactants = 2(63.5 + 16) + 2(35.5 + 1) = 159 + 73 = 232
Then atom economy = Mass of atoms in desired product/Mass of atom in reactant * 100/1
= 134/232 * 100 = 57.8%
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Write a balanced chemical equation for the formation of 1 mol of Cr2O3 (s) from Cr and O2 in their standard states
Answer:
4Cr + 3O2 -> 2Cr2O3
Explanation:
LS: 4Cr, 6O
RS: 4Cr, 6O
Percent composition of Fe2(SO3)4
Sulfate of iron. The elements that make up ferrous sulfate are 36.8% Fe, 21.1% S, and 42.1% O.
What function does ferrous sulfate serve?To treat and prevent iron deficiency anemia, a drug called ferrous sulfate—sometimes written sulphate—is taken is administered. The body uses iron to strengthen its red blood cells, which carry oxygen throughout the body.
Are iron and ferrous sulfate the same thing?For the treatment of iron-deficiency anemia, you can take ferrous sulfate as an iron supplement. If you don't obtain enough iron from your diet, you could need ferrous sulfate. Ferrous sulfate is available as a pill and a liquid.
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an isotope of cesium-137 has a half-life of 30 years. if 35.0 mg of cesium-137 disintegrates over a period of 90 years, how many mg of cesium-137 would remain?
4.375 mg of cesium-137 would remain after 90 years.
Cesium-137 has a half-life of 30 years, so over a period of 90 years, it would have undergone 3 half-lives.
The number of remaining nuclei after n half-lives is given by:
N(t) = N(0) * (1/2)^n, where
N(t) is the number of nuclei remaining after time t N(0) is the initial number of nuclei n is the number of half-lives that have passed.Since the initial amount of cesium-137 is 35.0 mg and the number of half-lives is 3, we can calculate the remaining amount of cesium-137 as:
N(90) = 35.0 mg * (1/2)^3
= 35.0 mg * (1/8)
= 4.375 mg
So, 4.375 mg of cesium-137 would remain after 90 years.
Key points:
Cesium-137 is an isotope that has a half-life of 30 years.A half-life is the amount of time it takes for half of the nuclei in a sample to decay.After one half-life, the number of remaining nuclei is half of the initial number.After two half-lives, the number of remaining nuclei is a quarter of the initial number.And so on, the number of remaining nuclei after 'n' half-lives is (1/2)^n of the initial number.Learn more about half-life here:
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