Answer:
what it mean I don't know
Calculate the pH and pOH of 500.0 mL of a phosphate solution that is 0.285 M HPO42– and 0.285 M PO43–. (Ka for HPO42- = 4.2x10-13 at 25°C)
Answer: when concentrations of acid and base are same, pH = pKa
PH = 12.38 pOH = 1.62
Explanation: pKa= -log(Ka)= 12.38. PH + pOH = 14.00
The pH of the solution is 12.38 and the pOH of the solution is 1.62.
Using the Henderson Hasselbalch equation;
pH = pKa + log [A-]/[HA]
Where;
pKa = - log Ka = -log[ 4.2x10-13] = 12.38
[A-] = [PO43–] = 0.285 M
[HA] = [HPO42-] = 0.285 M
Substituting values;
pH = 12.38 + [ 0.285 M]/[ 0.285 M]
pH = 12.38
But;
pH + pOH = 14
pOH = 14 - 12.38
pOH = 1.62
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Oxidation elements of the numbers H2CO2
What is the IUPAC name Of
CH3-CH2-CH2-CH=O
I
COOH
Answer:
Explanation:
It is Butanoic Acid
X^2/3-5X^1/3+6=0
find x
Answer:
[tex]x=27,8[/tex]
Explanation:
The equation is
[tex]x^{\dfrac{2}{3}}-5x^{\dfrac{1}{3}}+6=0[/tex]
Let,
[tex]x^{\dfrac{1}{3}}=y[/tex]
So,
[tex]y^2-5y+6=0\\\Rightarrow y=\dfrac{-\left(-5\right)\pm \sqrt{\left(-5\right)^2-4\times 1\times 6}}{2\times 1}\\\Rightarrow y=3,2[/tex]
[tex]x^{\dfrac{1}{3}}=y\\\Rightarrow y^3=x\\\Rightarrow x=3^3\\\Rightarrow x=27[/tex]
[tex]x=2^3\\\Rightarrow x=8[/tex]
Hence, [tex]x=27,8[/tex].
In addition to Earth, many of the other planets in the Solar System have atmospheres.
O True
O False
the answer is True.
each planet has a significant atmosphere
Answer:
True
Explanation:
bc i know
A car accelerates away from the starting line at 3.6 m/s2 and has the mass of 2400 kg. What is the net force acting on the vehicle?
Answer:
F = m x a
F = 2400 kg x 3.6 m/s2
F = 8,640 N
Explanation:
What is the purpose of replication?
1-to make an RNA template from DNA
2-to produce copies of a DNA molecule
3-to move mRNA through the ribosome
4-to change the number, type, or order of bases in DNA
Answer:
2-to produce copies of a DNA molecule
A common ancestor is an organism that is the
O direct ancestor of two or more different organisms
O direct ancestor of one organism.
O indirect ancestor of two or more different organisms.
O indirect ancestor of one organism.
A common ancestor is an organism that is the direct ancestor of two or more different organisms.
A common ancestor refers to an organism that is shared by multiple organisms, serving as the direct predecessor to those organisms. It is the point in evolutionary history where two or more distinct lineages diverged from a single ancestral lineage. This means that the common ancestor is the starting point from which different species or groups of organisms evolved over time.
In the context of evolution, organisms share common ancestry due to the process of descent with modification. Through genetic inheritance and gradual changes in traits over generations, new species arise from a common ancestor. As these species undergo divergent evolution, they develop distinct characteristics and adaptations, eventually becoming separate lineages.
Hence, the correct option is the direct ancestor of two or more different organisms.
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How many liters of nitrogen gas (N₂) are required to produce 7.5 x 10²⁶ molec NH₃ gas with excess of hydrogen gas at STP?
Answer: The volume of nitrogen gas that is required is 13944 L.
Explanation:
Given values:
Number of molecules of ammonia gas = [tex]7.5\times 10^{26}[/tex]
According to the mole concept:
[tex]6.022\times 10^{23}[/tex] number of molecules are present in 1 mole of a compound
So, [tex]7.5\times 10^{26}[/tex] number of molecules will be present in [tex]\frac{1}{6.022\times 10^{23}}\times 7.5\times 10^{26}=1.245\times 10^3 moles[/tex] of ammonia gas
The chemical equation for the formation of ammonia gas follows:
[tex]N_2 (g) + 3H_2(g) \rightarrow 2NH_3(g)[/tex]
According to the stoichiometry of the reaction:
2 moles of ammonia gas are produced from 1 mole of nitrogen gas
So, [tex]1.245\times 10^3[/tex] moles of ammonia gas will be produced from [tex]\frac{1}{2}\times 1.245 \times 10^3=6.225\times 10^2[/tex] moles of nitrogen gas
At STP conditions:
1 mole of a gas occupies 22.4 L of volume
So, [tex]6.225 \times 10^2[/tex] moles of nitrogen gas will occupy [tex]\frac{22.4 L}{1 mol}\times 6.225\times 10^2 moles=13944 L[/tex] of volume
Hence, the volume of nitrogen gas that is required is 13944 L.
Jen and her partner were assigned the Zn/Zn cathode/anode pair which they used to construct their electrolytic cell. They decided to keep the concentration of the corresponding Zn2+ solution constant at 1 M. If Jen ran her cell for 22.8 mins, what current (mA) did she use in order to transfer 9 x 10^-4 moles of electrons?
Answer:
63.2 mA
Explanation:
We all know that:
Current[tex]I = \dfrac{Q}{t}[/tex]
which can be further expressed as:
[tex]I = \dfrac{ne}{t}[/tex]
where;
n = number of electrons
e = charge on electrons
t = time (second)
Then; by replacing the values in the question, we have:
[tex]\dfrac{(9*10^{-4})\times6\times10^{23}\times1.6\times10^{-19}}{22.8\times60}[/tex]
[tex]= 0.06316 A \\ \\ \mathbf{I= 63.2 \ mA}[/tex]
Which of the following is an base?
OK₂CO₃
ОНЕ
NaCl
NaOH
Answer:
NaOH
Explanation:
NaOH is called base because it dissociates completely in aqueous solution to form hydroxide ion(OH-) and sodium cation (Na+). When it react with an acid , it produce sodium salt and water. It is a strong base because it dissociates completely.
What is the total number of electrons in the valence shell of an atom of aluminum in the ground
state?
1)8 2)2 3)3 4)10
Answer:
This is a total of ten electrons in filled shells
Explanation:
What is the oxidation state of the underlined atom in the reaction: NaHCO3 + HCl = NaCl + CO2 + H2O
underlined is the Na in NaHCO3
Answer:
+1
Explanation:
Let's consider the following equation.
NaHCO₃ + HCl ⇒ NaCl + CO₂ + H₂O
To determine the oxidation number of Na in NaHCO₃ we will use the following rule: the sum of the oxidation number of the elements present in a compound is equal to this charge. For this compound we know:
The oxidation number of H is +1.The oxidation number of C is +4.The oxidation number of O is -2.The charge of the compound is zero (neutral compound)Na + H + C + 3 O = 0
Na + (+1) + (+4) + 3 (-2) = 0
Na = +1
सच्याउंन आधानिक परियोडिक तालिका सफल भयो वा भएन, मूल्याङ्कन गनुहोस्
List out two demerits of Mendeleev's period table. Analyses modern penodic
table is able to overcome these dements or not.
दिदाको तालिका अध्ययन गरी सोधिएका प्रश्नहरुका उत्तर लेख्नुहोस्
Answer:llllIIII
Explanation:
Match the lettered empty blanks in the following statements to the correct word that makes each statement true. When a compound dissolves in water to produce an aqueous solution, the compound is said to be Blank A in water. If an aqueous solution conducts electricity, then the solute is called a(n) Blank B. Group of answer choices Blank A [ Choose ] Blank B electrolyte
Answer:
1. Soluble.
2. Electrolyte.
Explanation:
Solubility is a term used to describe how readily a substance can be dissolved in a solvent to form a solution. Thus, a substance is said to be soluble if it dissolves completely in a solvent and insoluble if it doesn't dissolve or only dissolves partially.
For example, sodium chloride (NaCl) when mixed with water dissociates into sodium and chloride ions. Thus, salt (sodium chloride) is said to be soluble because it dissolves completely in water.
In Chemistry, dissolution can be defined as the process of dissolving or dissociating a solute in solid, liquid or gaseous phase into fragmented particles by a solvent in order to form a solution. For dissolution to occur in solids, the crystalline structure of the substance must be broken up so as to release ions, atoms or molecules to produce a solution. For liquid and gases, the substance to be dissolved must form a non-covalent bond with the solvent to produce a solution.
Hence, a compound that dissolves in water to produce an aqueous solution is said to be soluble in water. Also, the solute of an aqueous solution that conducts electricity is called an electrolyte.
25 If the all the white mice are selected against in this environment (eaten by predators) what would happen to the gray mice if the environment were to change quickly to favor white mice? A. B. C. The gray mice would all change to white fur quickly and survive because the genetic traits are recessive and therefore still available in the population's genetics. The gray mice would immediately be eaten by the predators in the area and go extinct. The gray mice could still give birth to white mice if the trait remained in their genetic information and the population could produce white fur offspring which over time would succeed and reproduce causing an increase in white mice. The gray mice would have to move and white mice would move into the area causing the two to quickly develop different genetic traits and to evolve into entirely separate species until the two are no longer the same population. D.
Answer: The gray mice would immediately be eaten by the predators in the area and go extinct.
Explanation:
Natural selection is the differential survival of some members of the population of species which have better phenotypic advantage over others. Such members will survive and reproduce. According to the given situation, white mice were the choice of food for predators and the recessive trait of gray color of gray mice was favoring their survival as they may remain undetected by the predators. But the predators were able to detect the gray mice and changed their food preference from white to gray this way predators will consume all the gray mice and they may extinct in future as it is not possible to change the color of the fur from white to gray so quickly. The adaptation and passage of white trait among the members of the population will occur with a gradual change in successive generations of the population.
The pressure of a sample of dry air is held constant 2.25 atm while the temperature is
decreased from 100°C to 7.0°C. The original volume of the sample is 43 L. Which of
the following is closest to the final volume of the sample?
A) 3.0L
B) 32L
C) 57 L
D) 610 L
The pressure of a sample of dry air is held constant 2.25 atm while the temperature is decreased from 100°C to 7.0°C. The original volume of the sample is 43 L. 32 L is the closest to the final volume of the sample?
What is Charles's law?A law states that the volume of an ideal gas at constant pressure is directly proportional to the absolute temperature.
Charles’ law:
[tex]\frac{V_1}{T_1}[/tex] = [tex]\frac{V_2}{T_2}[/tex]
The volume and temperature of a fixed amount of gas at a constant pressure are directly proportional.
To use the equation, the temperature must be in Kelvin.
[tex]V_2[/tex] = [tex]\frac{V_1}{T_1} XT_2[/tex]
[tex]V_2[/tex] = 32 L
[tex]V_2[/tex]= 32 L
Hence, the correct answer is B.
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How many atoms of H are in 1 mole of NH3
Answer:
Before you use log you have to multiply the answer of 8.66 mol by 6.02⋅1023 by 3 because the answer of 8.66 mol by 6.02⋅1023 gives you the number of ammonia molecules and in each molecules there are 3 hydrogen atoms present.
Explanation:
how are electrons arranged in molecules of compounds?
Answer:
electrons are always in the outer shell
When an electron moves, it absorbs or produces energy in the form of photons. Electrons surround the nucleus, which is made up of protons and neutrons, and they all form an atom. The exchange or sharing of electrons between atoms is the main cause of chemical bonding.
Hope this helps you :)
What is the difference between Benedict’s test and Barfoeds test?
Answer:
Benedict's test would determine if the sample is a reducing sugar, and Barfoed's test would determine if it is a monosaccharide or disaccharide.
If a,b,c are in AP & x, y, z are in GP, prove that: x^(b-c).y^(c-a).z^(a- b) = 1
I will report if wrong.
Answer:
b
Explanation:
3. Jordan built a model of a neutral helium atom.
Nucleus
Proton
Neutron
Electron
What change would fix the mistake in Jordan's model?
Brainliest will be given to correct answer :)
Chemistry II Help please! Last question on my homework and I'm stuck.
Thank you!
Answer: [tex]\Delta G[/tex] for the reaction is -90kJ
Explanation:
The balanced chemical reaction is,
[tex]2H_2S(g)+SO_2(g)\rightarrow 3S_{rhombic}(s)+2H_2O(g)[/tex]
The expression for Gibbs free energy change is,
[tex]\Delta G=[n\times G_{products}]-[n\times G_{reactants}][/tex]
Putting the values we get :
[tex]\Delta G=[3\times G_f{S,rhombic}+2\times G_f{H_2O}]-[2\times G_f{H_2S}+1\times G_f{SO_2}][/tex]
[tex]\Delta G=[(3\times 0kJ/mol)+(2\times -229kJ/mol)]-[(2\times -34kJ/mol) +(1\times -300kJ/mol)][/tex]
[tex]\Delta G=-90kJ[/tex]
Thus [tex]\Delta G[/tex] for the reaction[tex]2H_2S(g)+SO_2(g)\rightarrow 3S_{rhombic}(s)+2H_2O(g)[/tex] is -90kJ
Be sure to answer all parts. Write the unbalanced chemical equation to represent each of the following reaction statement. Do not include phase abbreviations. (a) Potassium hydroxide and phosphoric acid react to form potassium phosphate and water. (b) Zinc and silver chloride react to form zinc chloride and silver. (c) Sodium hydrogen carbonate reacts to form sodium carbonate, water, and carbon dioxide. (d) Ammonium nitrite reacts to form nitrogen and water. (e) Carbon dioxide and potassium hydroxide react to form potassium carbonate and water.
Answer:
See explanation
Explanation:
An unbalanced chemical equation does not show equal number of atoms of each element on both sides of the reaction equation.
a) KOH + H3PO4 -----> K3PO4 + 3H20
b) Zn + AgCl -------> ZnCl2 + Ag
c) NaHCO3 → Na2CO3 + H2O + CO2
d) NH4NO2 ------> N2 + H2O
e) CO2 + KOH -----> K2CO3 + H2O
A hammer can be used to see how a mineral breaks. If you observe square chunks of the mineral when broken, what can you conclude?
a
The mineral is soft.
b
The mineral is hard.
c
The mineral has cleavage.
d
The mineral does not have cleavage.
Answer:
a
Explanation:
it can not break that easily
The mineral has given square chunks when breaked with a hammer. This indicates that the mineral has a cleavage. Thus, option c is correct.
What is mineral?Minerals are naturally formed inorganic substances which are having a definite chemical composition and highly ordered crystalline structures. Minerals are deposited in many organic and inorganic matters.
Minerals have some peculiarities such as hardness, cleavage, color etc. Cleavage of a mineral is its tendency to break along crystallographic planes thereby the structural locations of ions and atoms in the crystal creates planes of relative weakness.
Cleavage of crystal results in pieces of square, cubic or other geometrical shapes. in The mineral here, broken into square pieces indicating that the mineral have some weaker crystallographic planes in comparison to other and they cleave. Thus, c is correct.
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How many atoms would fit across a human hair? *
The amount of atoms one million carbon atoms or so make up an average human hair.
What are atoms?The smallest unit of matter that may be divided without ejecting electrically charged particles is called an atom. It is also the smallest material with properties resembling chemical elements. As a result, the atom serves as the fundamental unit of chemistry. In a chemical reaction, atoms cannot be formed or destroyed since they are indivisible units.
One inch has 25,400,000 nanometers. The width of a human hair ranges between 80,000 and 100,000 nanometers. The thickest human hair is a million times smaller than an atom. An atom's diameter spans from 0.1 to 0.5 nanometers. The volume of the cells is typically 0.009 cubic microns. More than 150,000 of these germs could fit on the tip of a human hair, and about 150 of them could fit within one Escherichia coli cell.
Thus, the amount of atoms one million carbon atoms or so make up an average human hair.
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If an element has 6 protons and its mass number is 14, how many neutrons and electrons does it have?
Answer:
8 neutrons and 6 electrons
Explanation:
Mass number= neutrons + protons
14=x+6
x=14-6
x=8
protons=electrons
6 protons=6 electrons
Identify the kind(s) of intermolecular forces that would occur between the solute and solvent in an acetic acid (which is polar and contains an OHOH group) solution. Check all that apply. Check all that apply. dispersion hydrogen bonding ion-dipole dipole-dipole
Explanation:
The acetic acid is a polar compound. The polar molecules have a positive and negative extreme for this reason they are dipoles. The dipoles can attract other dipoles or ions. So, it can establish ion-dipole and dipole-dipole forces with the solute. In addition, acetic acid has a hydroxyl group that can interact with hydrogens or other very electronegative atoms (oxygen, nitrogen and fluor) forming hydrogen bridge junctions.
How many grams of water can be formed from the reaction of 8.76 grams of H2 with 10.5 liters of O2 (at STP) according to the balanced equation: 2 H2 + O2 --> 2 H2O Express your answer to 3 sig figs. Do NOT include units!
Answer:
16.9g of H₂O can be formed
Explanation:
Based on the chemical reaction, 2 moles of H₂ react per mole of O₂. To anser this question we must find limiting reactant converting the mass and volume of each reactant to moles:
Moles H₂ -Molar mass: 2.016g/mol-:
8.76g * (1mol / 2.016g) = 4.345 moles
Moles O₂:
PV = nRT
PV/RT = n
P = 1atm at STP
V = 10.5L
R = 0.082atmL/molK
T = 273.15K at STP
n = 1atm*10.5L / 0.082atmL/molK*273.15K
n = 0.469 moles of oxygen
For a complete reaction of 4.345 moles moles of hydrogen are required:
4.345 moles H2 * (1mol O2 / 2mol H2) = 2.173 moles of O2 are required. As there are just 0.469 moles, Oxygen is limiting reactant
Now, 1 mole of O2 produce 2 moles of H2O. 0.469 moles will produce:
0.469 moles O₂ * (2 moles H₂O / 1mol O₂) = 0.938 moles H₂O.
The mass is -Molar mas H₂O = 18.01g/mol-:
0.938 moles * (18.01g/mol) =
16.9g of H₂O can be formeda. Identify which sets of quantum numbers are valid for an electron. Each set is ordered (n,ℓ,mℓ,ms).
Check all that apply.
3,1,-1,1/2
1,1,0,1/2
1,-1,-1,-1/2
2,1,-1,-1/2
3,0,0,1/2
0,2,1,-1/2
3,2,1,-1
4,3,3,-1/2
3,2,2,1/2
3,3,-1,1/2
4,3,-4,1/2
2,2,1,1/2
b. Consider the addition of an electron to the following atoms from the fifth period. Rank the atoms in order from the most negative to the least negative electron affinity values based on their electron configurations.
Atom or ion Electron configuration
I [Kr]4d105s25p5
Sn [Kr]4d105s25p2
Xe [Kr]4d105s25p6
Required:
Rank the electron affinity from most negative to least negative. To rank items as equivalent, overlap them.
Answer:
a. Values are - (1) 3,1,-1,1/2 (2) 2,1,-1,-1/2 (3) 3,0,0,1/2 (4) 4,3,3,-1/2
(5) 3,2,2,1/2
b. Order be- I > Sn > Xe
Explanation:
a.
Valid quantum numbers are -
'l' value should be less than 'n' value and 'ml' value should be '-l' to 'l'
'ml' value should not more than 'l' or 'n'.
Values are -
3,1,-1,1/2
2,1,-1,-1/2
3,0,0,1/2
4,3,3,-1/2
3,2,2,1/2
b.
Given that-
I [Kr]4d¹⁰5s²5p⁵
Sn [Kr]4d¹⁰5s²5p²
Xe [Kr]4d¹⁰5s²5p⁶
Order be-
I > Sn > Xe
Xe is least because it is completely filled outer shell (5s²5p⁶