In the titration of a weak acid with a strong base, the pH after adding 20.00 mL of base can be determined by considering the concentration of the weak acid and the remaining base after the reaction.
Explanation:To determine the pH after adding 20.00 mL of a 0.10 M strong base to a 40.00 mL sample of a 0.10 M weak acid with a Ka value of 1.8×10−5, we need to consider the reaction between the acid and the base.
Since the acid is weak, it does not dissociate completely. As a result, the pH can be calculated by considering the concentration of the weak acid and the remaining base after the reaction.
Using the titration curve as a reference, you can find the pH value corresponding to 20.00 mL of added base.
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According to Charles's law, under which conditions will the volume of a given amount of gas be proportional to temperature? when pressure and the number of moles increase when pressure and the number of moles decrease when pressure and the number of moles remain constant when the atmospheric pressure is 1.019 atm
Answer: when pressure and the number of moles remain constant
Explanation:
Charles' Law: This law states that volume is directly proportional to the temperature of the gas at constant pressure and number of moles.
[tex]V\propto T[/tex] (At constant pressure and number of moles)
[tex]{V_1\times T_1}={V_2\times T_2}[/tex]
where,
[tex]V_1[/tex] = initial volume of gas
[tex]V_2[/tex] = final volume of gas
[tex]T_1[/tex] = initial temperature of gas
[tex]T_2[/tex] = final temperature of gas
Therefore, the volume of gas is proportional to temperature when pressure and number of moles are constant.
Which substance is insoluble and floats in water? A) Ice shavings B) Wood shavings C) Salt crystals D) Sugar crystals
How many elements are in a compound that has a formula NiCI2+6H2O?
Use the changes in oxidation numbers to identify which atoms are oxidized and which are reduced in each reaction.
Final answer:
By assigning oxidation numbers, it is determined that Sr and O in H₂O are oxidized, while S in SO₃ and Kr are reduced in the given reactions. This identifies the substances undergoing oxidation and reduction.
Explanation:
To identify what is being oxidized and what is being reduced in each redox reaction, we first assign oxidation numbers to each atom in the reaction. The element whose oxidation number increases is oxidized, acting as the reducing agent. Conversely, the element whose oxidation number decreases is reduced, acting as the oxidizing agent.
Sr + SO₃ → SrSO₃: Sr goes from 0 to +2 (oxidized), and S in SO₃ goes from +4 to +6 (reduced).2KrF₂ + 2H₂O → 2Kr + 4HF + O₂: Kr goes from +2 to 0 (reduced), O in H₂O goes from -2 to 0 (oxidized).SO₃ + SCl₂ → SOCl₂ + SO₂: S in SO₃ goes from +6 to +4 in SO₂ (reduced), Cl in SCl₂ goes from +1 to -1 in SOCl₂ (oxidized).By tracking these changes in oxidation numbers, we can easily determine which substances are oxidized and which are reduced in these reactions. Remember, the oxidized substance loses electrons, and the reduced one gains electrons, according to the concept of redox reactions.
What mass of argon occupies 4.3 l at 70 kpa and 20 c?
To find the mass of argon gas at 4.3 liters, 70 kPa, and 20 °C, use the ideal gas law, convert units to atm and Kelvin, solve for moles, and then multiply by the molar mass of argon to obtain the mass, which is approximately 4.07 grams.
Explanation:The question asks for the mass of argon gas that occupies a volume of 4.3 liters at a pressure of 70 kPa and a temperature of 20 °C. To answer this, we can use the ideal gas law equation, PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature in Kelvin.
First, we convert the given temperature to Kelvin:
Next, we need to convert the pressure from kPa to atm, since the ideal gas constant (R) is typically given in L·atm/(mol·K):
We can then rearrange the ideal gas law to solve for the number of moles (n):
Using the values and R = 0.0821 L·atm/(mol·K), we calculate n:
Finally, using the molar mass of argon, which is about 39.948 g/mol, we find the mass:
Therefore, the mass of argon that occupies a volume of 4.3 liters at 70 kPa and 20 °C is approximately 4.07 grams.
4
Amelia is classifying plants in science lab. Her teacher describes a plant that has leaves, stems, roots, and that produces fruit.
How should Amelia classify the plant?
A.
moss
B.
non-flowering plant
C.
fern
D.
flowering plantAmelia is classifying plants in science lab. Her teacher describes a plant that has leaves, stems, roots, and that produces fruit. How should Amelia classify the plant
Answer:
D. flowering plant
Explanation:
Option A is incorrect because moss is a thalloid plant with no true plant body.
Option B is incorrect because the plant could not have produced fruits without flowering.
Option C is incorrect because ferns do not produce fruits.
The correct option is D. Flowering plants produce fruits and posses true leaves, stems and roots. The ovule of the flower becomes the seed after fertilization and the ovary becomes the fruit.
Copper crystallizes in a face centered cubic lattice. if the edge of the unit cell is 351 pm what is the radius of the copper atom
Final answer:
The atomic radius of a copper atom in a face-centered cubic lattice with an edge length of 351 pm is approximately 123.675 pm.
Explanation:
Calculating the Atomic Radius in a Face-Centered Cubic Lattice
For copper, which crystallizes in a face-centered cubic (FCC) lattice structure, we can calculate the atomic radius if we know the edge length of its unit cell. Given that the edge of the FCC unit cell is 351 pm, we can use the fact that the diagonal across the faces of the cube (√2 times the edge length) is equal to four times the atomic radius in an FCC lattice. This is because in an FCC structure, atoms touch along the face diagonal.
To calculate the atomic radius, we use the formula:
4r = √2 × edge length
Therefore: r = (√2 × 351 pm) / 4
r ≈ (1.414 × 351 pm) / 4
r ≈ 494.7 pm / 4
r ≈ 123.675 pm
The approximate radius of a copper atom in an FCC lattice is 123.675 pm.
In the Bronsted-Lowry model of acids and bases, a(n) _____ is a hydrogen donor and a(n) _____ is a hydrogen acceptor.
In the Bronsted-Lowry model of acids and bases, an acid is a hydrogen donor and a base is a hydrogen acceptor.
What is Bronsted-Lowry acid and base?Bronsted-Lowry acid is any substance that donates a proton or hydrogen ion while a Brønsted-Lowry base is that which accepts an hydrogen ion.
Based on this definition, it can be said that a Brønsted-Lowry acid must possess hydrogen ion(s) to donate.
Examples of Brønsted-Lowry acid are as follows:
HClHCNH2SO4Therefore, in the Bronsted-Lowry model of acids and bases, an acid is a hydrogen donor and a base is a hydrogen acceptor.
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The table shows the results of four surveys that randomly sampled 50 girls at a community center about their favorite sport at the center.
Swimming Basketball Soccer Total
Survey 1 16 15 19 50
Survey 2 15 15 20 50
Survey 3 7 35 8 50
Survey 4 14 18 18 50
Identify surveys that are likely biased. Based on the unbiased surveys, what percent of the girls at the community center are likely to choose swimming as their favorite sport?
14 %
23 %
26 %
30 %
Answer:
30%
Explanation:
Jeremy throws his ball up in the air, but the ball falls back to the ground. What force made the ball move without ever touching the ball?
Answer:
the naswer is gravity pulling on the ball
Explanation:
Why are the very lowest mass stars unable to fuse helium in their cores?
What is the volume occupied by 51.0 g of ammonia gas (nh3) at stp?
Answer : The volume of ammonia gas at STP is, 67.2 liters
Explanation : Given,
Mass of ammonia = 51.0 g
Molar mass of ammonia = 17 g/mole
As we know that,
At STP, 1 mole of gas contains 22.4 L volume of gas.
First we have to calculate the moles of ammonia gas.
[tex]\text{Moles of }NH_3=\frac{\text{Mass of }NH_3}{\text{Molar mass of }NH_3}=\frac{51.0g}{17g/mole}=3mole[/tex]
Now we have to calculate the volume of ammonia gas at STP.
As, 1 mole of ammonia gas contains 22.4 L volume of ammonia gas
So, 3 moles of ammonia gas contains [tex]3\times 22.4L=67.2L[/tex] volume of ammonia gas
Therefore, the volume of ammonia gas at STP is, 67.2 liters
Which would show an example of how physical changes are reversible ?
Answer:
Non-destructive physical changes
Explanation:
Hi, this is not a rule but most of the non-destructive physical changes are reversible.
In that group of changes you may find:
State changes (solidification, evaporation, etc.)Adsortion and desortionTemperature changes MixturesThink of a physical change and then try to figure out which process can reverse that.
A 55.50 g gas sample of a gas, at stp, has a volume of 15.0 l. calculate the molecular mass of the gas
The molecular mass of the gas is approximately 80.15 g/mol.
Explanation:To calculate the molecular mass of the gas, we first need to determine the number of moles of the gas. We can use the ideal gas law equation: PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature.
At STP (standard temperature and pressure), the pressure is 1 atm and the temperature is 273 K.
The volume of the gas is given as 15.0 L. We can rearrange the equation to solve for n, the number of moles:
n = PV / RT.
Substituting the given values, we have:
n = (1 atm) * (15.0 L) / (0.0821 L·atm/mol·K * 273 K).
Calculating this gives us n
= 0.6926 mol.
To calculate the molecular mass, we can divide the mass of the gas sample (55.50 g) by the number of moles (0.6926 mol).
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What is a functional group?
a group of organic molecules that work together to speed up reactions
a group of living things that are made up of organic compounds
a group of organs in the body that work together to perform a certain function
a group of atoms bonded to carbon that determines how the molecule will react
Answer:
A group of atoms bonded to carbon that determines how the molecule will react
Explanation:
Functional groups are atom or groups of atom attached to the organic compound in a specific manner.
Some of the examples of functional groups are:
-COOH, -Cl, -OH, -NO2, -COCl, -C=O, etc.
Functional groups determines the characteristics chemical properties of a organic compound.
The different organic compounds having same functional group undergoes same or similar type of reaction.
Sunspots appear dark because they are what ?
Sunspots appear dark because they are cooler than the surrounding areas of the sun's surface. The cooler temperature causes less light to be emitted, making the sunspots look dark.
Explanation:Sunspots appear dark because they are cooler than the surrounding areas of the sun's surface, also known as the photosphere. While they are still very hot, sunspots have temperatures of about 3,000 to 4,500 Kelvin, which is cooler than the average temperature of the photosphere, which is about 5,500 Kelvin. This difference in temperature causes less light to be emitted, and therefore the sunspots appear dark compared to the rest of the sun's surface
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Water molecules are made of slightly positively charged hydrogen atoms and slightly negatively charged oxygen atoms. which force keeps water molecules stuck to one another?
Water molecules are held together by an electromagnetic force known as hydrogen bonds. These bonds are a strong type of dipole-dipole interaction due to the partial positive charge of hydrogen atoms and partial negative charge of oxygen atoms. Option D is correct.
The electromagnetic force is responsible for keeping water molecules attracted to one another. More specifically, this attraction is due to hydrogen bonds, which are a strong type of intermolecular force. These bonds form because of the dipole interaction where the slightly positively charged hydrogen atoms of one water molecule are attracted to the slightly negatively charged oxygen atoms of another. Although individual hydrogen bonds are weaker than covalent and ionic bonds within molecules, they occur in large numbers in water, resulting in a significant force that holds the water molecules together.
Hydrogen bonds are particularly strong compared to other dipole-dipole interactions because of water's highly polar nature. This polarity is due to the oxygen atom in water being highly electronegative and possessing two lone pairs of electrons, resulting in a partial negative charge while the hydrogen atoms have a partial positive charge.
Hence, D. is the correct option.
The complete question is:
Water molecules are made of slightly positively charged hydrogen atoms and slightly negatively charged oxygen atoms. Which force keeps water molecules stuck to one another?
A.) Strong Nuclear
B.) Gravitational
C.) Weak Nuclear
D.) Electromagnetic
Why could a diet low in carbohydrates be dangerous?
A-The increased level of starches would provide excess energy.
B-The body could break down proteins from muscles for energy.
C-The increased level of fats could provide too many vitamins.
D-The body could take in too much dietary fiber, which harms cells.
Answer: Option B.
Explanation:
Low diet carbohydrates are the diets that limits the consumption of carbohydrates.
In low diet carbohydrates, food rich in carbohydrates are replaced by fat or proteins and suggested for the effective plan for weight loss.
Carbohydrates act as primary source of energy, in the absence of less amount of carbohydrates, body breaks down protein and fat into ketone for primary energy source that allows the body to undergo state called ketosis.
Thus, The correct answer is option B.
How many grams of MgCl2 will be obtained when 435 mL of 0.300 M HCl react with an excess of Mg(OH)2?
When a 2.5 mol of sugar (C12H22O11) are added to a certain amount of water the boiling point is raised by 1 Celsius degree. If 2.5 mol of aluminum nitrate is added to the same amount of water, by how much will the boiling point be changed? Use 3 – 4 sentences to explain your answer.
Please Help!
Will give most brainly
Answer is: boiling point will be changed by 4°C.
Chemical dissociation of aluminium nitrate in water: Al(NO₃)₃ → Al³⁺(aq) + 3NO⁻(aq).
Change in boiling point: ΔT =i · Kb · b.
Kb - molal boiling point elevation constant of water is 0.512°C/m, this the same for both solution.
b - molality, moles of solute per kilogram of solvent., this is also same for both solution, because ther is same amount of substance.
i - Van't Hoff factor.
Van't Hoff factor for sugar solution is 1, because sugar do not dissociate on ions.
Van't Hoff factor for aluminium nitrate solution is approximately 4, because it dissociates on four ions (one aluminium cation and three nitrate anions). So ΔT is four times bigger.
The answer should be 4°C....
What is the bond angle in a tetrahedral molecule? 120° 180° 109.5° 90°
The bond angle in a tetrahedral molecule is ideally 109.5° but can be slightly smaller in molecules like water and ammonia due to the presence of lone pairs of electrons.
Explanation:The bond angle in a tetrahedral molecule is 109.5°. However, it can differ slightly due to the effects of repulsion between atoms or if lone pairs of electrons are involved. For instance, in water, which has a tetrahedral structure, the angle is 104.5° due to the two lone pairs of electrons on the oxygen atom.
These lone pairs occupy more space, causing the bond angle to be slightly less than the ideal. Similarly, ammonia has a bond angle of 107.3° due to its one lone pair. Thus, while the ideal bond angle in a tetrahedral molecule is 109.5°, the presence of lone pairs can cause the angle to be slightly smaller.
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The formula for carbohydrates is C n H 2n O n . Which statement accurately describes this general formula?
A_There are more carbon atoms than oxygen atoms.
B_There are twice as many carbon atoms as hydrogen atoms.
C_The ratio of the atoms is 1:1:2 in the carbohydrate formula.
D_There are twice as many hydrogen atoms as carbon atoms.
Why do we use a double arrow in the dissociation equation for a weak acid answer?
The strength of an Arrhenius
acid determines percentage of ionization of acid and the number of H⁺ ions formed.
Strong acids completely ionize in water and give large amount ofhydrogen ions (H⁺), so we use only one arrow, because reaction goes in one direction and there no molecules of acid in solution.
For example hydrochloric acid: HCl(aq) → H⁺(aq) + Cl⁻(aq).
Weak acid partially ionize in water and give only a few hydrogen ions (H⁺), in the solution there molecules of acid and ions.
For example cyanide acid: HCN(aq) ⇄ H⁺(aq) + CN⁻(aq).
A double arrow is used in the dissociation equation for a weak acid to denote that the reaction is an equilibrium, indicating a reversible process where the weak acid partially dissociates and exists in dynamic balance with its ions.
Explanation:We use a double arrow in the dissociation equation for a weak acid to indicate that the reaction does not go to completion and remains at equilibrium. A weak acid partially donates its protons to the solution, leading to a dynamic equilibrium where the dissociation and re-association of the acid and its ions occur simultaneously. The double arrow (↔) represents the forward (acid losing a proton) and reverse (ion gaining a proton) reactions that happen at the same rate when the system is at equilibrium.
For example, the dissociation of acetic acid (CH₃COOH) in water is typically represented as:
CH₃COOH(aq) + H₂O(l) ↔ H₃O+ (aq) + CH₃COO(aq)
The corresponding equilibrium constant (Ka) for this reaction reflects the acid's tendency to dissociate and is calculated by the formula Ka = [H₃O+][CH₃COO] / [CH₃COOH]. A higher Ka value indicates a stronger acid, meaning it dissociates more. However, in weak acids, since they are not fully dissociated, their Ka values are relatively small.
What are the relative ion concentrations in an acid solution?
An Arrhenius base is a
substance that dissociates in water to form hydroxide ions (OH⁻).
For example lithium hydroxide is an Arrhenius base:
LiOH(aq) → Li⁺(aq) + OH⁻(aq).
Answer:
more H+ ions
Explanation:
How many ml of 0.112 M Pb(NO3)2 are needed to completely react with 10.0ml of a 0.105 M KI Given Pb(NO3)2 (aq) + 2KI(aq)=2KNO3(aq)?
Answer : The volume of [tex]Pb(NO_3)_2[/tex] needed are, 4.6875 ml
Explanation :
First we have to calculate the moles of [tex]KI[/tex].
[tex]\text{Moles of }KI=\text{Molarity of }KI\times \text{Volume of solution}=0.105mole/L\times 0.01L=0.00105mole[/tex]
Now we have to calculate the moles of [tex]Pb(NO_3)_2[/tex]
The given balanced chemical reaction is,
[tex]Pb(NO_3)_2(aq)+2KI(aq)\rightarrow 2KNO_3(aq)+PbI_2[/tex]
From the balanced chemical reaction, we conclude that
As, 2 moles of KI react with 1 mole of [tex]Pb(NO_3)_2[/tex]
So, 0.00105 moles of KI react with [tex]\frac{0.00105}{2}=0.000525[/tex] mole of [tex]Pb(NO_3)_2[/tex]
Now we have to calculate the volume of [tex]Pb(NO_3)_2[/tex]
[tex]\text{Volume of }Pb(NO_3)_2=\frac{\text{Moles of }Pb(NO_3)_2}{\text{Molarity of }Pb(NO_3)_2}[/tex]
[tex]\text{Volume of }Pb(NO_3)_2=\frac{0.000525mole}{0.112mole/L}=4.6875\times 10^{-3}L=4.6875ml[/tex]
conversion used : (1 L = 1000 ml)
Therefore, the volume of [tex]Pb(NO_3)_2[/tex] needed are, 4.6875 ml
Hydrocarbons are chain-like or ring-like molecules made of carbon and ________ atoms.
What volume of 0.205 m k3po4 solution is necessary to completely react with 130 ml of 0.0116 m nicl2?
See the picture to answer the question
the solid line is the results obtained when no catalyst was used and the broken line is the results obtained when a catalyst was used .how much energy must the system absorb for the reaction to start if no catalyst was used?
Whats the point of love?
All animals want to survive. With this in mind, lets talk about some natural drugs that your body creates to create this feeling of "love".
P.E.A. is a natural anti-depressant that the body makes, kind of like dopamine. This is the most affiliated with the nickname "love drug". It creates the need to reproduce sexually. This is the primal instinct; to reproduce and pass on your genetic material.
Now, as you stay with one partner, you may find that the feeling changes a bit; this is P.E.A. turning into oxytocin. This is a deeper kind of love that humans develop once they have been with a partner for long enough. High levels of oxytocin are found when a mother has a child, usually found during breastfeeding.
There are many natural drugs that your body produces to create the feeling of love. If you have any questions, let me know! Hope this helps!
A ping pong ball with a dent in it can be put into a pan of boiling water. After a short amount of time, the dent will pop out. Explain why this occurs.
Answer:
The right option is; b. the water caused an increase in temperature of the air inside the ball and an increase in pressure.
The dent (hollow area formed by pressing or hitting) from the ping-pong ball disappeared because energy was transferred from the hot boiling water in which the ball was placed to the air inside the ball. This transferred energy will increase the temperature of the air inside the ball and the air molecules will begin to move faster with a greater force. Hence, causing an increase in pressure.
Explanation: