Answer:
a. The diffusion of Na ions into the cell is facilitated by the Na concentration gradient across the plasma membrane.Explanation:
Cells differ in the concentration of Na+ and many other chemicals inside and out side of the cell, so diffusion of Na+ ions into the cell is facilitated by the Na+ concentration gradient across the membrane.
The diffusion of K+ ions out of the cell is also prevented by the electrical gradient across the plasma membrane.
In the cell, the electro chemical gradient is larger for Na+ than for K+ and many other substances.
Ions move across the cell membrane through channels, driven by the combined forces of the concentration gradient (chemical) and the electrical gradient. This process, known as diffusion, is influenced by the electrochemical gradient. The correct option is C.
Explanation:The driving forces for the diffusion of Na+ and K+ ions through their respective channels are dependent on both the concentration gradient and the electrical gradient, which together make up the electrochemical gradient. For Na+ ions, the concentration gradient facilitates their diffusion into the cell, as there are more Na+ ions outside the cell than inside (option a). However, the inside of the cell is typically negatively charged compared to the outside and there is an opposite electrical gradient, that impedes the transport of Na+ ions into the cell (option b). For the K+ ions, there are more inside the cell than outside, creating a concentration gradient that facilitates their diffusion out of the cell. However, the electrical gradient impedes this diffusion (option c).
Thus, ions move across the membrane via channels in a way that balances both the concentration (chemical) gradient and the electrical gradient to establish the electrochemical equilibrium.
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The solutions that are mixed contain agno3 and nacl. What two products can be formed by exchange of the ions from these two reactants?
Answer:
NaNO₃ and AgCl are the two products that can be formed.
Sodium nitrate, an aqueous solution and a solid silver chloride (precipitate)
Explanation:
We determine the dissociation of both salts
AgNO₃ (aq) → Ag⁺ (aq) + NO₃⁻ (aq)
NaCl (aq) → Na⁺ (aq) + Cl⁻ (aq)
We make the ionic equation:
Ag⁺ (aq) + NO₃⁻ (aq) + Na⁺ (aq) + Cl⁻ (aq) → NaNO₃(aq) + AgCl (s) ↓
NaNO₃ and AgCl are the two products that can be formed on exchanging ions.
Sodium nitrate, an aqueous solution and a solid silver chloride (precipitate)
Dissociation of salts:We determine the dissociation of both salts.
AgNO₃ (aq) → Ag⁺ (aq) + NO₃⁻ (aq)
NaCl (aq) → Na⁺ (aq) + Cl⁻ (aq)
Ionic equation:
Ag⁺ (aq) + NO₃⁻ (aq) + Na⁺ (aq) + Cl⁻ (aq) → NaNO₃(aq) + AgCl (s) ↓
Thus, NaNO₃ and AgCl are the two products that can be formed.
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A chemist must prepare 0.9 L of sodium hydroxide solution with a pH of 13.40 at 25°C. He will do this in three steps: Fill a 0.9 L volumetric flask about halfway with distilled water. Weigh out a small amount of solid sodium hydroxide and add it to the flask. Fill the flask to the mark with distilled water. Calculate the mass of sodium hydroxide that the chemist must weigh out in the second step.
Answer:
9.04 g
Explanation:
Given that:
pH of NaOH = 13.40
pOH = 14 - pH
pOH = 14 - 13.40
pOH = 0.6
Now, from there we can find the concentration of NaOH = [OH⁻]
= [tex]10^{-pOH}[/tex]
= [tex]10^{-0.6}[/tex]
= 0.2512 M
Given that; volume = 0.9 L
∴ number of moles of NaOH = volume × concentration of NaOH
= 0.9 × 0.2512
= 0.2261 moles
mass of NaOH = number of moles of NaOH × molar mass of NaOH
mass of NaOH = 0.2261 × 40
mass of NaOH = 9.04 g
Water expands when heated. Suppose a beaker of water is heated from 10℃ to 90℃. Does the pressure at the bottom of the beaker increase, decrease, or stay the same? Explain.
The pressure at the bottom of the beaker does increase when the water is heated from 10℃ to 90℃ due to the expansion of water and the resultant increase in height of the water column.
Explanation:When a beaker of water is heated from 10℃ to 90℃, the pressure at the bottom of the beaker increases. This is because as water expands when heated, the water columns above each point at the bottom of the beaker become taller. Since pressure in a fluid is given by the equation P = hρg (where P is pressure, h is the height of the fluid column, ρ is the density of the fluid, and g is the acceleration due to gravity), an increase in height (due to expansion of water) leads to an increase in pressure.
Additionally, it's important to note that while the density of the water decreases slightly as the temperature increases, the effect of the increased height of the water column on pressure outweighs the effect of the reduced density.
How many unpaired electrons in the F22+ ion are based on molecular orbital theory? The order of the molecular orbitals are (σ2s)(σ*2s)(σ2p)(π2p)(π*2p)(σ*2p).
Answer : The number of unpaired electrons in the [tex]F_2^{2+}[/tex] = 2
The bond order of [tex]F_2^{2+}[/tex] is, 2
Explanation :
According to the molecular orbital theory, the general molecular orbital configuration will be,
[tex](\sigma_{1s}),(\sigma_{1s}^*),(\sigma_{2s}),(\sigma_{2s}^*),(\sigma_{2p_z}),[(\pi_{2p_x})=(\pi_{2p_y})],[(\pi_{2p_x}^*)=(\pi_{2p_y}^*)],(\sigma_{2p_z}^*)[/tex]
As there are 9 electrons present in fluorine.
The number of electrons present in [tex]F_2^{2+}[/tex] molecule = 2(9) = 18 - 2 = 16
The molecular orbital configuration of [tex]F_2^{2+}[/tex] molecule will be,
[tex](\sigma_{1s})^2,(\sigma_{1s}^*)^2,(\sigma_{2s})^2,(\sigma_{2s}^*)^2,(\sigma_{2p_z})^2,[(\pi_{2p_x})^2=(\pi_{2p_y})^2],[(\pi_{2p_x}^*)^1=(\pi_{2p_y}^*)^1],(\sigma_{2p_z}^*)^0[/tex]
The number of unpaired electrons in the [tex]F_2^{2+}[/tex] = 2
The formula of bond order = [tex]\frac{1}{2}\times (\text{Number of bonding electrons}-\text{Number of anti-bonding electrons})[/tex]
The bonding order of [tex]F_2^{2+}[/tex] = [tex]\frac{1}{2}\times (10-6)=2[/tex]
The bond order of [tex]F_2^{2+}[/tex] is, 2
The elevation above the surface where a cloud first forms is called the ____. a. evaporation level b. level of free convection c. adiabatic zone d. condensation level
Answer:
d. condensation level
Explanation:
Condensation level is the elevation above the surface where a cloud first forms when air get into it. Because at that region, it is said that the humidity of the air will have reached it peak, then condensation starts to set in. As we equally known that when condensation occurs, water vapor in the air presumably changes into liquid water. So, we can therefore conclude that the significance of the condensation level is to assist in formation of clouds.
The __________ process of nlp normalizes words into base or root form.
Answers: The Stemming
The concentration of calcium in a cell is 0.3%. The concentration of calcium in the surrounding fluid is 0.1%. How could the cell obtain more calcium?
Answer:
Primary active transport
Explanation:
In a cell, the movement of molecules like calcium ions (Ca²⁺), to a region having high solute concentration from a region having low solute concentration, through the cell membrane requires metabolic energy and is known as Primary active transport.
It is given that the concentration of calcium in the cell (0.3%) is greater than the concentration of calcium in the fluid surrounding the cell (0.1%). So the calcium ions move into the cell and the cell obtains more calcium.
Therefore, the cell obtains more calcium by the process of Primary active transport.
Multiple _____ send combined messages to a bipolar cell, whereas a single _____ may link directly to a single bipolar cell. Please choose the correct answer from the following choices, and then select the submit answer button.
Answer:
Rods and Cone can best fill in the spaces.
Explanation:
Bipolar cells exist between photoreceptors (rod cells and cone cells) and ganglion cells. They act, directly or indirectly, to transmit signals from the photoreceptors to the ganglion cells.
Bipolar cells receive synaptic input from either rods or cones, or both rods and cones, though they are generally designated rod bipolar or cone bipolar cells. There are roughly 10 distinct forms of cone bipolar cells, however, only one rod bipolar cell, due to the rod receptor arriving later in the evolutionary history than the cone receptor.
In the dark, a photoreceptor (rod/cone) cell will release glutamate, which inhibits the ON bipolar cells and excites (depolarizes) the OFF bipolar cells. In light, however, light strikes the photoreceptor which causes the photoreceptor to be inhibited (hyperpolarized) due to the activation of opsins which activate All trans-Retinal, giving energy to stimulate G-Protein coupled receptors to activate phosphodiesterase (PDE) which cleaves cGMP into 5'-GMP. That is the mechanism of reaction.
Multiple photoreceptor cells send combined messages to a bipolar cell, and a single photoreceptor may directly link to a single bipolar cell.
The correct answer to the question is: Multiple photoreceptor cells send combined messages to a bipolar cell, whereas a single photoreceptor may link directly to a single bipolar cell. Photoreceptor cells are sensitive to light and transmit signals to ganglion cells that carry the signal to the brain. The communication between photoreceptors and bipolar cells in the retina is essential for visual processing.
Certain photoreceptors directly synapse onto bipolar cells, leading to direct effects, whereas other photoreceptors can synapse onto multiple bipolar cells, contributing to combined messages being sent through their graded postsynaptic potentials.
Florence often recalls the time when her children were young. While browsing through a store, she notices a cream-colored satin dress, edged with hand-made lace. It reminds her of a dress her daughter used to wear when she was little. She decides to buy the dress as a gift for her granddaughter. This is an example of _____.
Answer:
Autobiographical memory
Explanation:
Autobiographical memory is the memory of specific events that you experienced personally earlier in your life.
Advertising claims sometimes state that adding something mechanical to a car's engine will allow it to recover 100 percent of the energy that comes from burning gasoline. You should be skeptical of such claims because they violate the
A. first law of thermodynamics.
B. activation energy requirements of all chemical reactions.
C. second law of thermodynamics.D. law of conservation of matter
Answer:
second law of thermodynamics.
Explanation:
The second law of thermodynamics deals with interconversion of energy from one form to another. Although energy can be converted from one form to another, this conversion is never 100% efficient because energy is lost in certain ways such as through heat. In a combustion engine, it is not possible to recover the energy from the gasoline 100% since energy must be lost along the way via such means as heat losses. Hence I will be skeptical about such an advert.
Calculate the energy (in kJ) required to heat 10.1 g of liquid water from 55 oC to 100 oC and change it to steam at 100 oC. The specific heat capacity of liquid water is 4.18 J/goC, and the molar heat of vaporization of water is 40.6 kJ/mol.
Answer:
[tex]\large\boxed{\large\boxed{24.6kJ}}[/tex]
Explanation:
1. Energy to heat the liquid water from 55ºC to 100ºC
[tex]Q=m\times C\times \Delta T[/tex]
m = 10.1gC = 4.18g/JºCΔT = 100ºC - 55ºC = 45ºC[tex]Q=10.1g\times 4.18J/g\ºC\times 45\ºC=1,899.81J[/tex]
2. Energy to change the liquid to steam at 100ºC
[tex]L=\lambda \times n[/tex]
λ = 40.6kJ/moln = 10.1g / 18.015g/mol = 0.5606mol[tex]L=40.6kJ/mol\times 0.5604mol=22.76214kJ=22,762.14J[/tex]
3. Total energy
[tex]1,899.81J+22,762.14J=24,661.95J\approx24,662J\approx24.6kJ[/tex]
To heat and vaporize 10.1 g of water from 55 ℃ to 100 ℃, 1.893 kJ is required for heating and 22.7643 kJ for vaporization, resulting in a total energy requirement of 24.6573 kJ.
The student is asking about the calculation of energy to heat and vaporize water. To perform the calculation, we will use two different properties of water: its specific heat capacity and its molar heat of vaporization.
Firstly, we need to calculate the energy required to heat the water from 55 ℃ to 100 ℃. The specific heat capacity of liquid water is 4.184 J/g°C. Using the formula q = mcΔT, where q is the heat energy, m is the mass of the water, and ΔT is the temperature change, we can calculate the required energy to heat the water.
q = (10.1 g)(4.184 J/g°C)(100 ℃ - 55 ℃)= (10.1 g)(4.184 J/g°C)(45 ℃)= 1892.964 J or 1.893 kJ
Secondly, we calculate the energy required to vaporize the water at 100 ℃. We need the molar heat of vaporization of water, which is 40.6 kJ/mol. To do this, we convert the mass of water to moles (given that the molar mass of water is approximately 18.02 g/mol), and then multiply by the molar heat of vaporization.
Moles of water = mass of water / molar mass of water
= 10.1 g / 18.02 g/mol≈ 0.5605 mol
Energy for vaporization = moles of water × molar heat of vaporization
= 0.5605 mol × 40.6 kJ/mol≈ 22.7643 kJ
The total energy required is the sum of the energy to heat the water and the energy to vaporize it:
Total energy = energy to heat + energy to vaporize
= 1.893 kJ + 22.7643 kJ≈ 24.6573 kJ
The reaction between potassium chlorate and red phosphorus takes place when you strike a match on a matchbox. If you were to react 37.1 g of potassium chlorate () with excess red phosphorus, what mass of tetraphosphorus decaoxide () could be produced
25.55 grams of tetraphosphorus decaoxide could be produced by the reaction.
Explanation:
First the balanced chemical reaction of the production of tetraphosphorus decaoxide is to be known.
The chemical equation is
10 KClO3 + 3P4⇒ 3 P4010 + 10 KCl
The number of moles of KCLO3 will be calculated by the formula:
number of moles = mass of the compound given ÷ atomic mass of the compound
n = 37.1 ÷ 122.55 ( atomic mass of KClO3 is 122.55 gm/mole)
= 0.30 moles
From the stoichiometry
10 moles of KClO3 is required to produce 3 moles of P4O10
when 0.30 moles of KClO3 is used x moles of P4O10 is formed
thus, 3 ÷ 10 = x ÷ 0.30
= 0.09 moles of KClO3 is produced
To know the mass of P4O10 apply the formula
mass = number of moles × atomic mass
= 0.09 × 283.886 ( atomic mass of P4O10 is 283.88 gram/mole)
= 25.55 grams of P4O10 could be produced.
An empirical formula:__________ 1. gives the relative number of ions of each element per formula unit. 2. gives the number of ions of each element per formula unit. 3. uses lines to represent covalent bonds and shows how atoms in a molecule connect or bond to each other. 4. gives the relative number of atoms of each element per formula unit.5. gives the actual number of atoms of each element per formula unit.
Answer:
4. gives the relative number of atoms of each element per formula unit
Explanation:
An empirical formula -
It refers to the formula which determined the simplest whole - number ratio of all the atoms in a given species , is referred to as an empirical formula .
In simple terms ,
It is he smallest formula of the whole number which when multiplied by some whole number gives the actual structure of the compound .
Hence , from the given information of the question ,
The correct option for empirical formula is 4.
Final answer:
The empirical formula represents the simplest whole-number ratio of atoms of each element in a compound, distinguishing it from the molecular formula which shows the exact number of atoms.
Explanation:
An empirical formula is a representation of the relative number of atoms of each element in a chemical compound, showing the simplest whole-number ratio between the elements. It does not convey the actual numbers of atoms within a molecule but provides a simplified overview of the compound's composition. This characteristic distinguishes it from a molecular formula which details the exact number of atoms of each element present in a molecule. The empirical formula is fundamental in chemistry for understanding the basic composition of a compound and can be derived from the compound's percentage composition.
For example, the empirical formula of water (H2O) indicates that for every oxygen atom, there are two hydrogen atoms, presenting a ratio of 2:1. This reflects the simplest ratio of the atoms within the compound, regardless of how many molecules are present.
Now you will solve the same problem as above, but using the quadratic formula instead of iterations, to show that the same value of x is obtained either way. using the quadratic equation to calculate [h3o+] in 0.00250 m hno2, what are the values of a, b, c and x , where a, b, and c are the coefficients in the quadratic equation ax2+bx+c=0, and x is [h3o+]? recall that ka=4.5×10−4 .
Answer:
a: 1
b: 4.5x10⁻⁴
c: 1.125x10⁻⁶
[H₃O⁺] = 0.000859M
Explanation:
As HNO₂ is a weak acid, its equilibrium in water is:
HNO₂(aq) + H₂O(l) ⇄ H₃O⁺(aq) + NO₂⁻(aq)
Equilibrium constant, ka, is defined as:
ka = 4.5x10⁻⁴ = [H₃O⁺] [NO₂⁻] / [HNO₂] (1)
Equilibrium concentration of each specie are:
[HNO₂] = 0.00250M - x
[H₃O⁺] = x
[NO₂⁻] = x
Replacing in (1):
4.5x10⁻⁴ = x × x / 0.00250M - x
1.125x10⁻⁶ - 4.5x10⁻⁴x = x²
0 = x² + 4.5x10⁻⁴x - 1.125x10⁻⁶
As the quadratic equation is ax² + bx + c = 0
Coefficients are:
a: 1
b: 4.5x10⁻⁴
c: 1.125x10⁻⁶
Now, solving quadratic equation:
x = -0.0013 → False answer, there is no negative concentrations.
x = 0.000859
As [H₃O⁺] = x; [H₃O⁺] = 0.000859M
I hope it helps!
How many moles of solute are contained in 200 milliliters of a 1 m solution?
Answer:
0.2 moles of solute are in 200 mL
Explanation:
If we assume an aqueous solution, the solvent's density is 1g/mL
Solvent's volume = 200 mL
Solvent's density = Solvent's mass / Solvent's volume
Solvent's mass = solvent's density . solvent's volume → 200 mL . 1g/mL = 200 g
1 m means molality, we have 1 mol of solute in 1000 g of solvent, but in here the mass of solvent is 200 g. Let's make a rule of three:
1000 g of solvent have 1 mol of solute
Therefore, 200 g of solvent must have (200 .1) / 1000 = 0.2 moles
There are 0.2 moles of solute in 200 milliliters of a 1 M solution.
The question asks how many moles of solute are contained in 200 milliliters of a 1 m solution. To find the answer, we must understand the difference between molarity (M) and molality (m). Molarity is the number of moles of solute per liter of solution, while molality is the number of moles of solute per kilogram of solvent. However, taking into account that typically, a '1 M solution' is often used to denote molarity, and it is indicated that 1 M equals 1 mole solute in 1 liter solution, we can use this information.
First, we convert the volume from milliliters to liters assuming the usage of molarity. So, 200 milliliters is 0.2 liters. Then, we apply the formula for molarity:
moles solute = Molarity (M) imes Volume (L)
moles solute = 1 M imes 0.2 L
moles solute = 0.2 moles
Therefore, there are 0.2 moles of solute in 200 milliliters of a 1 m solution.
Jupiter's moon io was discovered to have high concentrations of sulfur oxides in its atmosphere. this, in combination with research into sulfur oxides relating to pollution on earth, has led to renewed interest in sulfur oxide compounds. scientists researching compounds present at low temperatures created disulfur dioxide. write the chemical formula for this compound.
Answer: The chemical formula of the given compound will be [tex]S_2O_2[/tex]
Explanation:
The compound formed is disulfur dioxide.
Covalent compound is defined as the compound which is formed by the sharing of electrons between the atoms forming a compound. These are usually formed when two non-metals react.
Disulfur dioxide is a covalent compound because sharing of electrons takes place between sulfur and oxygen. Both the elements are non-metals and hence, will form covalent bond.
The nomenclature of covalent compound is given by:
The less electronegative element is written first.The more electronegative element is written then, and a suffix is added with it. The suffix added is '-ide'.If atoms of an element is greater than 1, then prefixes are added which are 'mono' for 1 atom, 'di' for 2 atoms, 'tri' for 3 atoms and so on..Hence, the chemical formula of the given compound will be [tex]S_2O_2[/tex]
Final answer:
The chemical formula for disulfur dioxide is S₂O₂, composed of two sulfur atoms and two oxygen atoms.
Explanation:
The chemical formula for disulfur dioxide is S₂O₂. This compound consists of two sulfur atoms and two oxygen atoms. Disulfur dioxide is not as common as sulfur dioxide (SO₂), which is known for being a toxic gas with a strong odor and commonly discussed in relation to atmospheric pollution and volcanic emissions. In the context of Jupiter's moon Io, sulfur dioxide plays a significant role due to the volcanic activity there, causing sulfur and sulfur dioxide to recondense as particles and affect the moon's atmosphere and surface.
A solid metal cube has an edge which is 11.4 mm long, and a mass of 6.67 g. What is the density of the cube? (A cube has all sides of equal length.) MULTIPLE CHOICE:
(a) 5.85 g/cm3 (b) 1.71 g/mm3 (c) 4.50 g/cm3 (d) 0.0877 g cm3
Answer:
d = 4.50 g/cm³
Explanation:
Given data:
Edge length of a cube = 11.4 mm (11.4/10 = 1.14 cm)
Mass of cube = 6.67 g
Density = ?
Solution:
Density:
Density is equal to the mass of substance divided by its volume.
Units:
SI unit of density is Kg/m3.
Other units are given below,
g/cm3, g/mL , kg/L
Formula:
D=m/v
D= density
m=mass
V=volume
Symbol:
The symbol used for density is called rho. It is represented by ρ. However letter D can also be used to represent the density.
First of all we will calculate the volume of cube.
Volume = length × width × height
Since all are equal,that's why
Volume = 1.14 cm × 1.14 cm × 1.14 cm
Volume = 1.482 cm³
d = m/v
d = 6.67 g/ 1.482 cm³
d = 4.50 g/cm³
1) An aerosol can contains gases under a pressure of 4.50 atm at 20.0 degrees Celsius. If the can is left on a hot, sandy beach, the pressure of the gases increases to 4.78 atm. What is the Celsius temperature on the beach? HINT: Temperature must be in Kelvin while solving the problem.
2) A sample of gas contains NO, NO2, and N2O. The pressure of the gas mixture is 4.68 atm. The pressure of NO is 501.6 mm Hg, whereas the pressure of NO2 is 2.54 atm. What is the pressure of N2O? HINT: All pressure units must be the same.
Answer:
Explanation:
1) An aerosol can contains gases under a pressure of 4.50 atm at 20.0 degrees Celsius. If the can is left on a hot, sandy beach, the pressure of the gases increases to 4.78 atm. What is the Celsius temperature on the beach?
Given data:
Initial pressure = 4.50 atm
Initial temperature = 20.0°C (20 +273 = 293 K)
Final pressure = 4.78 atm
Final temperature = ? (in °C)
Solution:
According to the Gay-Lussac law,
The temperature of given constant amount of a gas at constant volume is directly proportional to its absolute temperature.
Mathematical expression:
P₁/T₁ = P₂/T₂
P₁ = Initial pressure
T₁ = Initial temperature
P₂ = Final pressure
T₂ = Final temperature
Now we will put the values:
P₁/T₁ = P₂/T₂
4.50 atm / 293 k = 4.78 atm / T₂
T₂ = 4.78 atm. 293 k / 4.50 atm
T₂ = 1400.54 atm.K / 4.50 atm
T₂ = = 311.23 k
K to °C
311.23 k - 273.15 = 38.08°C
2) A sample of gas contains NO, NO2, and N2O. The pressure of the gas mixture is 4.68 atm. The pressure of NO is 501.6 mm Hg, whereas the pressure of NO2 is 2.54 atm. What is the pressure of N2O? HINT: All pressure units must be the same.
Given data:
Total pressure of gaseous mixture = 4.68 atm
Pressure of NO = 501.6 mmHg
Pressure of NO₂ = 2.54 atm
Pressure of N₂O = ?
Solution:
The given problem will be solve through the Dalton law of partial pressure.
According to this law,
" The total pressure of mixture of a gas is equal to the sum of partial pressure of all the component of gas"
Now we will convert the pressure of NO₂ in to atm.
Pressure of NO = 501.6/760 = 0.66 atm
Formula:
Total pressure = partial pressure of NO + partial pressure of NO₂ + partial pressure of N₂O
4.68 atm = 0.66 atm + 2.54 atm + partial pressure of N₂O
4.68 atm = 3.2 atm + partial pressure of N₂O
Partial pressure of N₂O = 4.68 atm - 3.2 atm
Partial pressure of N₂O = 1.48 atm
To confirm the answer:
Total pressure = partial pressure of NO + partial pressure of NO₂ + partial pressure of N₂O
4.68 atm = 0.66 atm + 2.54 atm + 1.48 atm
4.68 atm = 4.68 atm
According to the atomic theory, ________. Group of answer choices a compound can contain different numbers of atoms as long as it has the same kinds of atoms atoms are neither created nor destroyed during a chemical reaction all atoms are different all matter is made up of tiny particles called electrons atoms of the same element combine to form compounds
According to the atomic theory, atoms are neither created nor destroyed during a chemical reaction. This emphasizes the Law of Conservation of Mass and the principle that atoms combine in simple whole number ratios to form compounds.
Explanation:According to the atomic theory, atoms are neither created nor destroyed during a chemical reaction. This principle is a part of Dalton's atomic theory, which lays the foundation for our understanding of chemical reactions. In essence, this law, often referred to as the Law of Conservation of Mass, indicates that in a chemical reaction, atoms are rearranged to form new substances, but the total number of atoms remains unchanged.
All matter is composed of atoms, which are the basic building blocks of matter. Atoms of the same element have identical properties, while atoms of different elements have unique properties. These atoms can combine in simple whole number ratios to form chemical compounds, adhering to the principle that atoms are indivisible in chemical processes.
Understanding this aspect of atomic theory is crucial for grasping the fundamentals of chemistry, as it underlines the conservation of mass in chemical reactions and the formation of compounds from atoms in specific ratios.
Cyclohexane has a freezing point of 6.50 ∘C and a Kf of 20.0 ∘C/m. What is the freezing point of a solution made by dissolving 0.771 g of biphenyl (C12H10) in 25.0 g of cyclohexane?
Answer: [tex]2.49^0C[/tex]
Explanation:
Depression in freezing point is:
[tex]T_f^0-T_f=i\times k_f\times \frac{w_2\times 1000}{M_2\times w_1}[/tex]
where,
[tex]T_f[/tex] = freezing point of solution = ?
[tex]T^o_f[/tex] = freezing point of solvent (cyclohexane) = [tex]6.50^oC[/tex]
[tex]k_f[/tex] = freezing point constant of solvent (cyclohexane) = [tex]20.0^oC/m[/tex]
m = molality
i = Van't Hoff factor = 1 (for non-electrolyte)
[tex]w_2[/tex] = mass of solute (biphenyl) = 0.771 g
[tex]w_1[/tex] = mass of solvent (cyclohexane) = 25.0 g
[tex]M_2[/tex] = molar mass of solute (biphenyl) =
Now put all the given values in the above formula, we get:
[tex](6.50-T_f)^oC=1\times (20.0^oC/m)\times \frac{(0.771g)\times 1000}{154\times (25.0g)}[/tex]
[tex](6.50-T_f)^oC=4.01[/tex]
[tex]T_f=2.49^0C[/tex]
Therefore, the freezing point of a solution made by dissolving 0.771 g of biphenyl in 25.0 g of cyclohexane is [tex]2.49^0C[/tex]
The freezing point of a solution made by dissolving 0.771 g of biphenyl in 25.0 g of cyclohexane is 2.50 °C. This is calculated using the freezing point depression formula with the cryoscopic constant and the molality of the solution.
Explanation:The freezing point of a solution made by dissolving 0.771 g of biphenyl (C12H10) in 25.0 g of cyclohexane can be calculated using the concept of freezing point depression. The formula to calculate the freezing point depression (ΔTf) is given by ΔTf = i * Kf * m, where ΔTf is the freezing point depression, i is the van't Hoff factor (which is 1 for non-electrolytes like biphenyl), Kf is the cryoscopic constant of the solvent, and m is the molality of the solute in the solution.
First, we need to calculate the molality of biphenyl in cyclohexane, which is calculated by moles of biphenyl per kilogram of cyclohexane. The molar mass of biphenyl (C12H10) is 154.21 g/mol. Therefore, moles of biphenyl = 0.771 g / 154.21 g/mol = 0.005 moles. Since there is 25.0 g of cyclohexane, this is equivalent to 0.025 kg. Thus, molality (m) = 0.005 moles / 0.025 kg = 0.2 mol/kg.
Using the provided cryoscopic constant (Kf) for cyclohexane, which is 20.0 °C/m, we can calculate the freezing point depression: ΔTf = 1 * 20.0 °C/m * 0.2 = 4.0 °C.
Finally, the freezing point of the solution is the freezing point of pure cyclohexane (6.50 °C) minus the freezing point depression (ΔTf): 6.50 °C - 4.0 °C = 2.50 °C.
A typical aspirin tablet contains 325 mg of acetylsalicylic acid (HC9H7O4). Calculate the pH of a solution that is prepared by dissolving two aspirin tablets in one cup (237 mL) of solution. Assume the aspirin tablets are pure acetylsalicylic acid, Ka=3.3×10−4.
Answer:
pH =2.685
Explanation:
mass of acetylsalicylic acid, m = 2 × 325 m g × (1 g / 1000 m g )
= 0.65 g
Volume V = 237mL
dissociation constant, Ka =3.3×10⁻⁴
molecular weight of acetylsalicylic acid = 180.1 g/mol
mass of acetylsalicylic acid, (HC₉H₇O₄)
= 0.65 / 180.1
= 0.0036mol
concentration of HC₉H₇O₄ in a 237 mL solution
M = 0.0036 / 237ML
= 0.015M
in a 237 mL solution HC₉H₇O₄ in water is
C₉H₇O₄⁻ ⇄ H⁺
Next, we show the changes in different phases that occur during the dissociation process. We use the value x as the concentration loss/gained during the dissociation process,
HC₉H₇O₄ C₉H₇O₄⁻ H⁺
Initial 0.015 0 0
change -x x x
equilibrium 0.015 -x x x
The equation for the dissociation constant Ka ,
[tex]K_a = \frac{[C_9H_7O_4^-[H^+]]}{[HC_9H_7O_4]} \\3.3 * 10^-^4 = \frac{x * x}{0.015 - x} \\4.95 * 10^-^6-3.3 * 10 ^-^4x = x^2\\[/tex]
using quadratic equation
x² + 3.3 * 10⁻⁴x - 4.95 * 10 ⁻⁶ = 0
x = 0.002066M
pH = -log[H⁺]
pH = -log[0.002066]
= 2.685
What is the Percent yield made if 3.9 grams of a substance were made experimentally while you calculated 3.6 grams of substance using Stoichiometry?
Answer:
Percent yield = 108%
Explanation:
Percent yield is the ratio of experimental yield and the theoretical yield multiplied by 100.The expression for the percent yield is given as,
Percent yield = experimental yield/theoretical yield *100
Percent yield = (3.9/3.6 )*100 = 108%
A generic salt, AB 2 , has a molar mass of 345 g/mol and a solubility of 8.70 g/L at 25 °C. AB 2 (s) − ⇀ ↽ − A 2 + (aq) + 2B − (aq) What is the K sp of this salt at 25 °C
Answer : The value of [tex]K_{sp}[/tex] of the generic salt is, [tex]1.60\times 10^{-5}[/tex]
Explanation :
As we are given that, a solubility of salt is, 8.70 g/L that means 8.70 grams of salt present in 1 L of solution.
First we have to calculate the moles of salt [tex](AB_2)[/tex]
[tex]\text{Moles of }AB_2=\frac{\text{Mass of }AB_2}{\text{Molar mass of }AB_2}[/tex]
Molar mass of [tex]AB_2[/tex] = 345 g/mol
[tex]\text{Moles of }AB_2=\frac{8.70g}{345g/mol}=0.0252mol[/tex]
Now we have to calculate the concentration of [tex]A^{2+}\text{ and }B^-[/tex]
The equilibrium chemical reaction will be:
[tex]AB_2(s)\rightleftharpoons A^{2+}(aq)+2B^-(aq)[/tex]
Concentration of [tex]A^{2+}[/tex] = [tex]\frac{0.0252mol}{1L}=0.0252M[/tex]
Concentration of [tex]B^-[/tex] = [tex]\frac{0.0252mol}{1L}=0.0252M[/tex]
The solubility constant expression for this reaction is:
[tex]K_{sp}=[A^{2+}][B^-]^2[/tex]
Now put all the given values in this expression, we get:
[tex]K_{sp}=(0.0252M)\times (0.0252M)^2[/tex]
[tex]K_{sp}=1.60\times 10^{-5}[/tex]
Thus, the value of [tex]K_{sp}[/tex] of the generic salt is, [tex]1.60\times 10^{-5}[/tex]
To isolate the benzoic acid from the bicarbonate solution, you should
Answer:
it is acidified with concentrated hydrochloric acid.
2. After quenching your solution with ice, the resulting aqueous layer became acidic. Use a chemical equation to explain how the solution became acidic
Answer:
C2H5Cl + H20 ⇆ C2OOH4
Explanation:
The left over acetyl chloride which reacted with water to produce acetic acid
For the chemical reaction HCN ( aq ) + KOH ( aq ) ⟶ H 2 O ( l ) + KCN ( aq ) HCN(aq)+KOH(aq)⟶H2O(l)+KCN(aq) write the net ionic equation, including the phases. net ionic equation:
The net ionic equation for the reaction HCN(aq) + KOH(aq) ⟶ H2O(l) + KCN(aq) is: H+ (aq) + OH- (aq) ⟶ H2O(l), after factoring out the spectator ions.
Explanation:The subject of this question is the net ionic equation for the chemical reaction HCN(aq) + KOH(aq) ⟶ H2O(l) + KCN(aq). First, we write out the full molecular equation. Secondly, we break all aqueous compounds (those in a water solution) down into their ions, resulting in the total or full ionic equation. We then eliminate ions that show up on both sides of the equation as they don't play a part in the actual chemical reaction and are thus 'spectators'. What remains is termed the net ionic equation.
The full molecular equation is: HCN(aq) + KOH(aq) ⟶ H2O(l) + KCN(aq). The full ionic equation is: H+ (aq) + CN- (aq) + K+ (aq) + OH- (aq) ⟶ H2O(l) + K+ (aq) + CN- (aq). From this, the K+ (aq) and CN- (aq) are on both sides and can be eliminated as spectator ions. Thus, the net ionic equation is: H+ (aq) + OH- (aq) ⟶ H2O(l).
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For the reaction [tex]HCN (aq) + KOH (aq) \rightarrow H_2O (l) + KCN (aq)[/tex], the net ionic equation is [tex]HCN (aq) + OH^- (aq) \rightarrow H_2O (l) + CN^- (aq)[/tex] .
For the chemical reaction [tex]HCN (aq) + KOH (aq) \rightarrow H_2O (l) + KCN (aq)[/tex], let's write the net ionic equation including the phases:
First, we'll break down the reaction into its ionic components:
HCN (aq) stays as HCN because it's a weak acid and doesn't dissociate completely in water.KOH (aq) dissociates into [tex]K^+[/tex] (aq) and [tex]OH^-[/tex] (aq).The products include H2O (l) and KCN (aq), where KCN dissociates into [tex]K^+[/tex] (aq) and [tex]CN^-[/tex] (aq).The complete ionic equation is:
[tex]HCN (aq) + K^+ (aq) + OH^- (aq) \rightarrow H_2O (l) + K^+ (aq) + CN^- (aq)[/tex]
Next, we cancel out the spectator ions (K+) to get the net ionic equation:
[tex]HCN (aq) + OH^- (aq) \rightarrow H_2O (l) + CN^- (aq)[/tex]
Write a chemical equation that illustrates the autoionization of water.
Answer:
The autoionization of water is:
2H₂O ⇄ H₃O⁺ + OH⁻ Kw
Explanation
2 moles of water can generate hydronium and hydroxide, when they work as an acid or as a base
If we take account that the concentration of protons (hydroniums), at the standard temperature is 1×10⁻⁷ M, it can be considered that the molarity of water is a constant that can be incorporated into a “greater” constant that also includes to Kc and that is known as ionic product of water, Kw. The expression is:
Kw = [H₃O⁺] . [OH⁻] / [H₂O]²
We do not include water → Kw = [H₃O⁺] . [OH⁻]
Since the water dissociation reaction produces the same concentration of H₃O⁺ as OH⁻, [OH⁻] in pure water will also be 1×10⁻⁷ M
Kw = 1×10⁻⁷ . 1×10⁻⁷ = 1×10⁻¹⁴
pKw = pH + pOH
14 = 7 + 7
The autoionization of water can be represented by the chemical equation H2O(l) + H2O(l) -> H3O+ (aq) + OH- (aq). At 25 °C, two out of every billion water molecules are ionized, resulting in the formation of hydronium ions and hydroxide ions. The equilibrium constant for this process is Kw, which has a value of 1.0 × 10-14 at 25 °C.
Explanation:The autoionization of water can be represented by the chemical equation:
H2O(l) + H2O(l) → H3O+ (aq) + OH–(aq)
The equilibrium constant for this reaction is called the ion-product constant for water, Kw. At 25 °C, Kw has a value of 1.0 × 10-14. This indicates that at this temperature, approximately two out of every billion water molecules undergo autoionization to produce hydronium ions (H3O+) and hydroxide ions (OH–).
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How do humans contribute to these excessive levels of phosphorus
Final answer:
Humans contribute to excessive levels of phosphorus through the use of phosphorus-containing detergents, artificial fertilizers, and runoff from animal husbandry. This leads to eutrophication in aquatic ecosystems.
Explanation:
Humans contribute to excessive levels of phosphorus through activities such as using detergents that contain phosphorus, using artificial fertilizers that contain phosphorus, and runoff from animal husbandry. When phosphorus-containing detergents were introduced in the 1950s, it increased the amount of phosphorus available to algae and other plant life in wastewater. This led to excessive growth of algae in lakes, which decreased oxygen levels and caused harm to fish and other aquatic organisms.
A student adds 4.00g of dry ice (solid CO2) to an empty balloon. What will be the volume of the balloon at STP after all the dry ice sublimes (converts to gaseous CO2)
According to the ideal gas law, the sum of the absolute temperature of the gas and the universal gas constant is equal to the product of the pressure and volume of one gram of an ideal gas. The volume of the balloon is 2.016 L.
The general gas equation, commonly referred to as the ideal gas law, represents the state of a fictitious ideal gas through an equation. The ideal gas law approximates the behavior of several gases under numerous conditions, despite the fact that it has a number of drawbacks.
n = (4.00 g) / (44.01 g/mol)
n = 0.090 mol
V = nRT / P
V = (0.090mol) × (0.08206 L atm / (mol K)) × (273 K) / (1 atm)
V = 2.016 L
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Using the ideal gas law and the conditions of STP, the volume of the balloon after the dry ice has sublimed would be approximately 2.24 liters.
Explanation:To solve this, we need to use the ideal gas law: PV=nRT, where P is pressure, V is
volume, n is number of moles, R is the ideal gas constant, and T is temperature. Given that the question mentions.
Standard Temperature and Pressure (STP), we know that P is 1 atmosphere and T is 273.15 K. First, calculate n by dividing the mass of CO2 (4.00g) by its molar mass (~44.01 g/mol). This gives approximately 0.09 moles. Plug these values into the ideal gas law, making sure to use R's value for volume in liters (0.0821 L*atm/mol*K). This yields a final
volume of approximately 2.24 liters.
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A sample of solid NH 4HS is placed in a closed vessel and allowed to equilibrate. Calculate the equilibrium partial pressure (atm) of ammonia, assuming that some solid NH 4HS remains.
Answer:
The answer to the question is
The equilibrium partial pressure (atm) of ammonia, assuming that some solid NH₄HS remains 0.26 atm.
Explanation:
To solve the question, we write out the chemical equation as follows
NH₄HS (s) ⇄ NH₃ (g) + H₂S (g)
From the above equation, it is observed that only the gaseous products contribute to the partial pressure
Kp =PNH₃·PH₂S where at Kp = 0.070 and PNH₃, PH₂S are the partial pressures of the gases
However since the number of moles of both gases are equal, therefore by Avogadro's law PNH₃ = PH₂S
Then PNH₃ = √(0.07) = PH₂S = 0.2645 atm. ≅ 0.26 atm.