What was the total demand by all counties for water from the Sweetbriar River Basin in 1970? What is it projected to be in 2020?
What is the [H+] of a solution with a pH of 6.6? Use a scientific calculator.
2.5 × 107
5.0 × 105
8.3 × 106
7.7 × 105
Considering the definition of pH, the concentration [H⁺] is 2.5 ×10⁻⁷ M.
Definition of pHpH is the Hydrogen Potential. It is a measure of acidity or alkalinity that indicates the amount of hydrogen ions present in a solution or substance.
Mathematically, pH is calculated as the negative base 10 logarithm of the activity of hydrogen ions:
pH= - log [H⁺]
The numerical scale that measures the pH of substances includes the numbers from 0 to 14. The pH value 7 corresponds to neutral substances. Acidic substances are those with a pH lower than 7, while basic substances have a pH higher than 7.
Concentration [H⁺] of the solutionIn this case, being pH= 6.6, you can replace this value in the definition of pH:
6.6 = -log [H⁺]
Solving:
[H⁺]= 10⁻⁶ ⁶ M
[H⁺]= 2.5 ×10⁻⁷ M
Finally, the concentration [H⁺] is 2.5 ×10⁻⁷ M.
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Why is a spectrum for a given element unique for that element?
A. No element has more than two electrons in the first shell.
B. Each element has a unique arrangement of electrons.
C. Atoms of different elements have different masses.
D. Atomic nuclei contain no electrons.
Answer:
B
Explanation:
Which changes are evidence of a chemical reaction? a beaker of water becomes hot to the touch upon?
Which particles in an atom could demonstrate that opposite charges attract?
A.
a neutron and an electron
B.
two protons together
C.
a proton and a neutron
D.
a proton and an electron
Consider the balanced equation below.
What is the mole ratio of Fe3O4 to Fe?
1:3
1:4
3:1
4:3
Answer:
1:3
Explanation:
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I am studying for ACS and have trouble understanding how to rank molecules in decreasing or increasing solubility in water...
I know the rules of which molecules are insoluable...But how do you rank them in which is least or most soluble.
The question in the acs included
In which set are the substances arranged in order of decreasing solubility in water?
(A) Al(OH)3 > Mg(OH)2 > NaOH
(B) BaSO4 > CaSO4 > MgSO4
(C) CaCO3 > NaHCO3 > Na2CO3
(D) AgCl > AgBr > AgI
How many grams of sodium chloride are present in a 0.75 M solution with a volume of 500.0 milliliters? 0.38 grams 22 grams 0.75 grams 44 grams
How do most vertebrates reproduce—sexually or asexually? What are gametes? How is an embryo produced?
I NEED THE ANSWER QUICK
Sucrose is another name for table sugar. Sucrose is a compound made from the elements carbon, hydrogen, and oxygen. Which statement best describes the properties of sucrose?
Sucrose is a disaccharide compound of glucose and fructose and forms a homogeneous solution when dissolved in water. The physical and chemical properties of sucrose are quite different from its constituent elements in their individual states.
Explanation:Sucrose, also known as table sugar, is a compound made of the elements carbon, hydrogen, and oxygen. Structurally, it's a disaccharide, meaning it consists of two sugar units; in this case glucose and fructose. Sucrose has covalent bonds and is a crystalline solid at room temperature. When dissolved in water, it forms a homogeneous solution where its molecules are uniformly distributed among the water molecules. These are some of the key properties of sucrose.
It's important to note that the properties of the sucrose molecule vastly differ from the properties of its constituent elements when in their free, or uncombined, state. Carbon, for instance, is a black solid and hydrogen and oxygen are colorless gases when uncombined, but when they chemically combine, they form the white, crystalline solid that is sucrose.
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What is the ph of a buffer that is 0.6 m hf and 0.2 m naf ? the k a of hf is 6.8 × 10 −4 ?
Henderson–Hasselbalch equation: pH = pKa + log(c(NaF)/c(HF)).
pH = -log(6,8·10⁻⁴) + log (0,2 M/0,6 M).
pH = 3,17 - 0,48.
pH = 2,69.
Answer:
pH of buffer is 2.69
Explanation:
According to Henderson-Hasselbalch equation for a buffer consists of an weak acid (HF) and it's conjugate base ([tex]F^{-}[/tex])-
[tex]pH=pK_{a}(HF)+log(\frac{C_{F^{-}}}{C_{HF}})[/tex]
Where C stands for concentration
[tex]pK_{a}=-log(K_{a})[/tex]
[tex]C_{F^{-}}[/tex] in 0.2 m NaF is 0.2 m
[tex]C_{HF}=0.6m[/tex]
So, [tex]pH=-log(6.8\times 10^{-4})+log(\frac{0.2}{0.6})=2.69[/tex]
1.
Which best describes the shape of myoglobin, which in many ways is a typical protein?
a complex three-dimensional shape formed from many twisted helixes
a cylindrical shape that forms from a single twisted helix
a straight chain, like beads on a straight piece of string
a highly-branched chain, much like the branches of a maple tree
An increase in temperature can disturb the liquid-vapor equilibrium
True
False
Use ksp=4.87×10−17 to calculate the solubility of iron (ii) hydroxide in pure water in grams per 100.0 ml of solution. g
The solubility product constant is the equilibrium constant of a substance in an aqueous solution. The solubility of iron (ii) hydroxide is [tex]2.07 \times 10^{-5}\;\rm g.[/tex]
What is Ksp?Ksp is the solubility product constant, which is given as the product of the concentration of cation and anion dissociated in the aqueous solution.
Given,
Ksp = [tex]4.87 \times 10^{-17}[/tex]
Thus,
[tex]\begin{aligned}&= \rm [Fe^{2+}][OH^{-}]^{2} \\\\&= \rm (X)(2X)^{2} \\\\&= \rm 4X^{3}\end{aligned}[/tex]
The molarity can be calculated as:
[tex]\begin{aligned}\rm 4X^{3} =4.87 \times 10^{-17}\\\\\rm X= 2.30 \times 10^{-6}\;\rm M\end{aligned}[/tex]
The mass of iron (ii) hydroxide in 100 mL of water is calculated as:
[tex]\begin{aligned}2.30 \times 10^{-6} \;\rm mol/L &= 2.3 \times 10^{-5}\;\rm mole/100 mL\\\\&= 2.07 \times 10^{-5} \;\rm g\end{aligned}[/tex]
Therefore, the solubility of iron (ii) hydroxide is [tex]2.07 \times 10^{-5}\;\rm g.[/tex]
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If the molecular mass of tetraoxosulphate(VI) acid is 98, calculate it's vapour density.
How much heat is absorbed by 15.5 g of water when its temperature is increased from 20.0°C to 50.0°C? The specific heat of water is 4.184 J/(g°C).,
Answer : The heat absorbed by the water is 19.4 kJ
Explanation :
Formula used :
[tex]Q=m\times c\times \Delta T[/tex]
or,
[tex]Q=m\times c\times (T_2-T_1)[/tex]
where,
Q = heat absorbed = ?
m = mass of water = 15.5 g
c = specific heat of water = [tex]4.184J/g^oC[/tex]
[tex]T_1[/tex] = initial temperature = [tex]20.0^oC[/tex]
[tex]T_2[/tex] = final temperature = [tex]50.0^oC[/tex]
Now put all the given value in the above formula, we get:
[tex]Q=15.5g\times 4.184J/g^oC\times (50.0-20.0)^oC[/tex]
[tex]Q=1945.56J=1.94\times 10^3J=1.94kJ[/tex]
Therefore, the heat absorbed by the water is 19.4 kJ
What happens to an atom of fluorine (f) when it forms an ionic bond in which it has the same electron configuration as the noble gas neon?
There are two types of chemical compound one is covalent compound and other is ionic compound, covalent compound formed by sharing of electron and ionic compound formed by complete transfer of electron. Therefore, one electron will be gained by fluorine during the reaction.
What is chemical Compound?Chemical Compound is a combination of molecule, Molecule forms by combination of element and element forms by combination of atoms in fixed proportion.
The compound that is ionic in nature can be dissociated very easily in water. Since ionic compounds are polar in nature, they readily dissolve in water. When an atom of fluorine (f) when it forms an ionic bond in which it has the same electron configuration as the noble gas neon, one electron will be gained by fluorine to form negative charge anion.
Therefore, one electron will be gained by fluorine during the reaction.
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What type of stress is caused by two plates sliding past one another?
EASY AND IMPORTANT What do you think is the most challenging aspect of using a microscope? What are the advantages and disadvantages of using a microscope to look at trace evidence?
The most challenging aspect is focusing the microscope.
Microscopes enables us to view objects that cannot be seen with the human eye alone.
A disadvantage is that not all types of evidence can be clearly seen.
What is a microscope?A microscope is an instrument that is used to view tiny and microscopic objects.
In using a microscope, the most challenging aspect is focusing the microscope.
An advantage of microscopes is that they enable us to view objects that cannot be seen with the human eye alone.
A disadvantage though is that not all evidence can be clearly seen.
In conclusion, a microscope helps one to view trace and tiny objects.
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Write the dissociation reaction and the corresponding ka equilibrium expression for hcn in water
The dissociation reaction of HCN in water is HCN(aq) ↔ H⁺(aq) + CN⁻(aq).
Here is the balanced dissociation reaction for hydrocyanic acid (HCN) in water:
HCN(aq) ↔ H⁺(aq) + CN⁻(aq)
The equilibrium expression for the acid dissociation constant (Ka) for this reaction is given by:
Ka = [H⁺][CN⁻] / [HCN]
This expression shows that the equilibrium constant (Ka) for HCN dissociation is determined by the concentrations of the hydrogen ions (H⁺), the cyanide ions (CN⁻), and the undissociated hydrocyanic acid (HCN) in the solution.
Nitrogen reacts with oxygen to form two compounds. compound a contains 2.8 g of nitrogen for each 1.6 g of oxygen. compound b contains 5.6 g of nitrogen for each 9.6 g of oxygen. what is the lowest whole-number mass ratio of nitrogen that combines with a given mass of oxygen?
4130 J of energy 52g water 10 c initial specific heat 4.18 J waht would the final temperature be
What is the maximum amount of kcl that can dissolve in 200 g of water? (the solubility of kcl is 34 g / 100 g h 2o at 20°c.) 6800 g 34 g 68 g 17 g?
How many liters of fluorine gas, at 298 K and 0.98 atm, will react with 23.5 grams of potassium metal? Show all of the work used to solve this problem. 2K + F2 2KF
What is the percent by mass of nahco3 in a solution containing 10 g of nahco3 dissolved in 400 ml of h2o?
What is the mass, in grams, of 7.20×1020 molecules of caffeine, c8h10n4o2?
Answer: 0.23 grams
Explanation:
According to avogadro's law, 1 mole of every substance weighs equal to its molecular mass and contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.
To calculate the number of moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given molecules}}{\text{Avogadro's number}}=\frac{7.20\times 10^{20}}{6.023\times 10^{23}}=1.2\times 10^{-3}moles[/tex]
1 mole of caffeine [tex](C_8H_{10}N_4O_2)[/tex] weighs = 194 g
[tex]1.2\times 10^{-3}[/tex] moles of [tex](C_8H_{10}N_4O_2)[/tex] weigh = [tex]\frac{194}{1}\times 1.2\times 10^{-3}=0.23g[/tex]
Thus mass of caffeine [tex](C_8H_{10}N_4O_2)[/tex] is 0.23 grams.
Describe how to make 1.50 liters of a 0.01 M ammonium chloride solution
Which of the following is NOT an assumption of the kinetic theory of gases?
A)Gas particles are in constant random motion.
B)The volume of individual gas particles is zero.
C)The particles in a gas are attracted to each other.
D)Gas particles collide without losing energy.
c) The particles in a gas are attracted to each other
explain in terms of collision theory, how and why a reactions's rate changes as the reaction progresses
Explanation:
According to collision theory, more is the number of collisions occurring between the combining substances more will be the rate of reaction.
Factors that affect rate of a reaction are as follows.
Temperature - Increase in temperature leads to increase in kinetic energy of particles due to which there occurs more number of collisions between them. As a result, rate of reaction will increase leading to increase in rapid formation of products.
Surface area - More is the surface area of a substance, less will be the interaction between solute and solvent particles. And, when there occurs decrease in surface area then interaction between solute and solvent particles increases. This leads to increase in rate of reaction.
Concentration of reactants - More is the concentration of reactant molecules more is the availability of molecule interaction. As a result, more number of collisions occur leading to increase in rate of a reaction.
1. A 10 g gold coin is heated from 25°C to 50°C (CAu is 0.13 J/g-°C). What is the H?
(Points : 1)
+32.5 J
25 J
+25 J
- 32.5 J
I know it is 32.5 J but is it negative or positive... I say it is negative, but I could be wrong...,
Answer:
+32.5 J
Explanation: