What volume of a 0.303 m hydroiodic acid solution is required to neutralize 20.5 ml of a 0.167 m calcium hydroxide solution?
1.What percent of light passes through the sample if its absorbance A=2?
2. For the best calibration curve, the transmittance values (%T) should fall within the range from 10% to 90%. What is the approximate range of corresponding absorbance values?
3. What is the absorbance of the solution if the percent transmittance for it is 10%?
1. The formula for absorbance is given as:
A = log (Io / I)
where A is absorbance, Io is initial intensity, and I is final light intensity
log (Io / I) = A
log (Io / I) = 2
Io / I = 100
Taking the reverse which is I / Io:
I / Io = 1 / 100
I / Io = 0.01
Therefore this means that only 0.01 fraction of light or 1% passes through the sample.
2. What is meant by transmittance values is actually the value of I / Io. So calculating for A:
at 10% transmittance = 0.10
A = log (Io / I)
A = log (1 / 0.10)
A = 1
at 90% transmittance = 0.90
A = log (Io / I)
A = log (1 / 0.90)
A = 0.046
So the absorbance should be from 0.046 to 1
3. at 10% transmittance = 0.10
A = log (Io / I)
A = log (1 / 0.10)
A = 1
How would you calculate the number of nanometers in 8.1 cm
Solid iron(iii) sulfide is oxidized by oxygen gas to solid iron(iii) oxide and sulfur dioxide gas. express your answer as a chemical equation. identify all of the phases in your answer.
Iron(III) sulfide reacts with oxygen to produce iron(III) oxide and sulfur dioxide. The reaction can be represented by this balanced chemical equation: 4 Fe2S3(s) + 11 O2(g) -> 2 Fe2O3(s) + 12 SO2(g). This is an example of a combination reaction; a type of redox reaction.
Explanation:The reaction of solid iron(III) sulfide (Fe2S3) with oxygen gas (O2) produces solid iron(III) oxide (Fe2O3) and sulfur dioxide gas (SO2). The chemical equation representing this reaction is:
4 Fe2S3(s) + 11 O2(g) -> 2 Fe2O3(s) + 12 SO2(g)
In this equation, (s) represents solid, (g) represents gas, and the numbers in front of the chemical formulas are coefficients indicating the number of moles of each substance involved in the reaction. This reaction is an example of a combination reaction, which is a type of oxidation-reduction (or redox) reaction where a substance reacts with oxygen to form oxides.
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Why do covalent compounds have significantly lower melting/boiling points than ionic compounds?
The best way to learn is through questioning. Explain in full sentences please..
in terms of spacing of particles what would be necessary to change from solid to gas what is the process called and how is it achieved
To change from a solid to a gas, particles must gain sufficient energy to overcome intermolecular forces, a process known as sublimation when it occurs directly, or through melting and evaporation in two steps. This significantly increases the substance's volume. Sublimation and deposition are energy-involving phase transitions affected by temperature and pressure changes.
To change from a solid to a gas, particles need to gain enough energy to overcome their intermolecular interactions and disperse throughout the available space. This increase in energy allows the particles to move from a closely packed structure to one where they move about randomly and independently. This process is known as sublimation when a solid turns directly into a gas without passing through the liquid phase. However, typically a solid will first melt into a liquid and then the liquid will evaporate into a gas. This is achieved through the addition of energy, which can come from heat, for example.
The characteristic increase in volume that accompanies this transition is considerable. During the transition from liquid to gas especially, the volume of a substance can increase by a factor of 1,000 or more. Sublimation and the reverse process, deposition (where a gas becomes a solid directly), are facilitated by changes in temperature and pressure, and these phase transitions are both isothermal and involve a measurable change in energy.
At the molecular level, each state of matter—solid, liquid, gas—has different properties. Solids have particles in a fixed arrangement, while in liquids particles are still in contact but can move past one another. The gas phase is a state in which particles are separated by large distances relative to their size and move independently in a container, expanding to fill its shape and volume.
What mass of sodium oxalate na2c2o4 is needed to prepare 0.250 l of a 0.100 m solution?
Answer:
3.35 g Na2C2O4
Explanation:
They gave us the molarity and the liters of solution so using the relationship (M=mol/V) we can get the moles of solution.
0.250 L (0.100 mol/L) = 0.0250 mol Na2C2O4
Now that we have the moles of sodium oxalate, we can use its molar mass (134 g/mol) to convert to grams.
0.0250 mol (134.0 g/mol) -=3.35 grams (rounded to three sig figs
Approximately 3.35 grams of sodium oxalate (Na2C2O4) are needed to prepare 0.250 L of a 0.100 M solution.
The mass of sodium oxalate (Na2C2O4) needed to prepare a 0.100 M (mol/L) solution in a volume of 0.250 L, we can use the formula:
Mass = molar concentration × molar mass × volume
First, we need to calculate the number of moles of sodium oxalate required:
Number of moles = molar concentration × volume
Number of moles = 0.100 mol/L × 0.250 L
Number of moles = 0.025 mol
The molar mass of sodium oxalate (Na2C2O4) can be calculated as follows:
Molar mass = (2 × atomic mass of sodium) + (2 × atomic mass of carbon) + (4 × atomic mass of oxygen)
Molar mass = (2 × 22.99 g/mol) + (2 × 12.01 g/mol) + (4 × 16.00 g/mol)
Molar mass = 134.03 g/mol
Finally, we can calculate the mass of sodium oxalate needed:
Mass = number of moles × molar mass
Mass = 0.025 mol × 134.03 g/mol
Mass = 3.35 g
Therefore, approximately 3.35 grams of sodium oxalate (Na2C2O4) are needed to prepare 0.250 L of a 0.100 M solution.
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What determines whether or not a substance can be actively transported through the membrane?
An electron is on a -2.5 eV energy level. the electron is stuck by a 2.5 eV photon. What will most likely happen?
Ionic compounds are electrically overall thereofre the sum of
What trend does the first ionization energy follow going across the periodic table?
Explanation:
Ionization energy is defined as the energy necessary to remove an electron from a gaseous atom or ion.
Therefore, smaller is the size of an atom or ion more energy it needs to remove an electron because more is the charge on an ion smaller will be its size.
Hence, more will be the attraction between nucleus and valence electrons of the atom. So, more difficulty is faced by the atom to lose an electron. As a result, ionization energy will increase.
Across the period, there will be decrease in size of elements of the periodic table.
Thus, we can conclude that there will be increase in first ionization energy across the periodic table.
A sample of ammonia has a mass of 82.9 g. how many molecules are in this sample?
Answer: [tex]29.37\times 10^{23}molecules [/tex]
Explanation: To calculate the moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\textMolar mass}}[/tex]
Given mass of ammonia [tex]NH_3[/tex] given = 82.9 g
Molar mass of ammonia [tex]NH_3[/tex] = 17 g/mol
Putting values in above equation, we get:
[tex]\text{Moles of sodium}=\frac{82.9g}{17g/mol}=4.87mol[/tex]
According to Avogadro's law,
1 mole of any substance contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.
Thus 4.87 moles of ammonia contains=[tex]\frac{6.023\times 10^{23}}{1}\times 4.87=29.37\times 10^{23}molecules [/tex] of ammonia.
Approximately how much more energy is released in a 6.5 richter magnitude earthquake than in one with magnitude 5.5?
a. 3 times
b. 300 times
c. 30 times
d. 3000 times
The type of energy present in the bonds between atoms is
How many electrons would be expected in the outermost electron shell of an atom with atomic number 12?
Final answer:
A neutral magnesium (Mg) atom, with atomic number 12, has 2 electrons in its outermost shell.
Explanation:
The atom with atomic number 12 is magnesium (Mg), and according to its electronic configuration, it has 12 electrons.
In a neutral magnesium atom, the first shell (1s) is filled with 2 electrons, the second shell (2s and 2p) contains a total of 8 electrons, and the third and outermost shell has 2 electrons, as expressed in the electronic configuration of Mg (1s²2s²2p¶3s²).
Therefore, the number of electrons in the outermost electron shell of an atom with atomic number 12 would be 2.
The compound Ba(NO3)2 includes _____ oxygen atoms.
6
3
5
2
To determine the number of oxygen atoms in the given compound, barium nitrate Ba(NO3)2, we can see that in each mole of barium nitrate, there are 6 moles of oxygen atoms in it. In this problem, the correct answer is D.
6 moles of oxygen.
Explanation:
Ba(NO3)2 ,is a composite called 'barium nitrate.' It's also described as 'barium dinitrate.' Ba(NO3)2 is created up of atoms of barium (Ba), nitrogen (N) and oxygen (O). Barium nitrate is the inorganic compound with the chemical equation Ba(NO3)2. It, like most barium salts, is transparent, toxic, and water-soluble. It fires with a green flame and is an oxidizer, it is practiced in pyrotechnics.
Is it necessary that compounds be colored to be separated by chromatography?
What happens to the light as the ocean increases in depth? Explain
The ocean is much too deep for light to penetrate, thus it cannot reach the bottom of the water. Electromagnetic radiation that the human eye can detect as light.
What is light?Electromagnetic radiation that the human eye can detect as light. From radio waves with wavelengths measured in meters to gamma rays with wavelengths shorter than roughly 1 1011 meter, electromagnetic radiation occurs throughout a very broad range of wavelengths.
The wavelengths of light that are visible to humans fall into a relatively small range within that wide spectrum, ranging from about 700 nanometers for red light to roughly 400 nm for violet light. Infrared and ultraviolet are two spectral bands that are close to the visible band and are frequently referred to as light as well. The ocean is much too deep for light to penetrate, thus it cannot reach the bottom of the water.
Therefore, the ocean is much too deep for light to penetrate, thus it cannot reach the bottom of the water.
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The sterile saline solution used to rinse contact lenses can be made by dissolving 400 mg of nacl in sterile water and diluting to 100 ml. what is the molarity of the solution?
The molarity of the NaCl solution is calculated to be 0.0685 M.
To calculate the molarity of the solution, we need to determine the number of moles of NaCl dissolved in the solution. First, we convert 400 mg of NaCl to grams:
400 mg = 0.400 g
Using the molar mass of NaCl (58.44 g/mol), we find the number of moles:
Number of moles = 0.400 g / 58.44 g/mol ≈ 0.00685 moles
The volume of the solution is 100 mL, which we convert to liters:
Volume in liters = 100 mL / 1000 mL/L = 0.1 L
Finally, we calculate the molarity (M) of the solution:
Molarity (M) = Number of moles / Volume in liters = 0.00685 moles / 0.1 L = 0.0685 M
Therefore, the molarity of the NaCl solution is 0.0685 M.
Is the reaction mg²⁺(aq) + h₂o(l) → mgo(s) + 2h⁺(aq) endothermic or exothermic?
The reaction is likely exothermic as bond formation is usually accompanied by release of energy. However, without enthalpy values of the reactants and products, it is hard to definitively classify the reaction.
Explanation:The reaction stated, mg²⁺(aq) + h₂o(l) → mgo(s) + 2h⁺(aq), does not directly tell us whether it's endothermic or exothermic. However, we can try to infer the nature of the reaction based on general principles. Endothermic reactions usually involve the breaking of bonds, which requires energy, whereas exothermic reactions involve the formation of new bonds, which usually releases energy. By looking at the equation, it can be inferred that a bond formation (MgO) is taking place and energy likely being released, which suggests that the reaction is exothermic. However, without specific enthalpy values of the reactants and products, it would be hard to definitively classify the reaction as endothermic or exothermic.
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Which atom is least likely to form an ion? which atom is least likely to form an ion? carbon, c aluminum, al bromine, br phosphorus, p?
Answer:
Aluminum
Explanation:
Its the same as the top on but easier to understand
and the top one was approved so.................its right
N2(g) + o2(g) → 2 no(g) δh = +180.7 kj 2 no(g) + o2(g) → 2 no2(g) δh = −113.1 kj 2 n2o(g) → 2 n2(g) + o2(g) δh = −163.2 kj use hess's law to calculate δh for the reaction. n2(g) + 2 o2(g) → 2 no2(g).
What is the chemical formula for an amino group?
The amino group has the chemical formula -NH₂.
It consists of a nitrogen atom that is bonded to two hydrogen atoms, and to the carbon skeleton of a molecule. This functional group is a key component of amino acids, which are the building blocks of proteins.
For example, glycine is an amino acid where the amino group is bonded to an alpha carbon atom, along with a hydrogen atom, carboxyl group (-COOH), and a side chain represented by the R group.The general structure of an amino acid can be represented as R-CH(NH₂)-COOH. Different amino acids vary in their R group, which determines their unique properties. In biochemistry, the amino acids with an amino group and a carboxyl group attached to the same carbon atom are referred to as alpha-amino acids.
Compounds which are characterized as covalent are generally made up of elements found in which part of the periodic table
Answer:
upper right of the periodic table
When aluminum oxidizes in air, it forms aluminum oxide (ai2o3): 4ai (s) + o2 (g_ -> 2ai2o3 (s) if a 77 g sheet of aluminum oxide formed completely in excess oxygen, how many grams of aluminum were oxidized?
Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore, 78 g of aluminum were oxidized.
What is mole?The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity or amount of substance. We know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number. Stoichiometry represents the number of moles.
4 Al + 3 O[tex]_2[/tex]→ Al[tex]_2[/tex]O[tex]_3[/tex]
moles of aluminium oxide = 77 g/101.96
moles of aluminium oxide=0.75moles
The mole ratio of aluminium oxide to aluminium is 1:3
moles of aluminium= 4×0.75moles
moles of aluminium= 3 moles
mass of aluminium = moles × molar mass
mass of aluminium= 3 ×26
mass of aluminium = 78 g
Therefore, 78 g of aluminum were oxidized.
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A compound contains 3 nitrate ions for every 1 aluminum ion. what is the chemical formula?
Which of these acids forms when wine is left exposed to oxygen for extended periods?
A lithium ion is much less reactive than a lithium atom because it
A reaction which forms a solid product is an example of a(n): gas evolution reaction. combustion reaction. precipitation reaction. oxidation-reduction reaction. none of the above