Which of the following aqueous solutions are good buffer systems?
a. 0.34 M calcium iodide + 0.22 M sodium iodide.
b. 0.27 M ammonia + 0.38 M ammonium nitrate.
c. 0.27 M nitric acid + 0.18 M sodium nitrate.
d. 0.18 M hydrofluoric acid + 0.14 M hydroiodic acid.
e. 0.14 M calcium hydroxide + 0.28 M calcium chloride.
Answer:
b. 0.27 M ammonia + 0.38 M ammonium nitrate.
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to bear to mind the fact that buffest must be prepared by using either of the following pairs:
weak acid/conjugate base
weak base/conjugate acid
So that the pH might be set constant. In such a way, since a. shows two salts, c. a strong acid with a neutral base, d, shows two acids and e. a strong base with a neutral base, we infer the correct buffer is b. 0.27 M ammonia + 0.38 M ammonium nitrate because it has a weak base (ammonia) and its conjugate acid, ammonium.
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The literature values listed for the unknowns in this assignment are from either the Merck Index or the CRC Handbook, the two most used reference handbooks. However, the values tend to vary slightly across literature sources and sometimes the temperatures are given as ranges. Give at least one reason for the variations in these reported temperatures.
In general, the boiling points of compounds increase down a group in the periodic table. The melting points and boiling points for the hydrogen compounds of group 6A elements are in the table below.
Melting point (0C) Boiling point (oC)
H2O 0.0 100.0
H2S -82.0 -60.0
H2Se -65.7 -41.2
H2Te -49.0 -2.2
Answer:
See explanation
Explanation:
One of the important trends in the periodic table is electronegativity. Electro negativity decreases down the group and increases across the period. This trend has important consequences on the observed properties of the compounds of elements in a particular group in the periodic table.
As we move down in group 6A, the electro negativity of the elements elements the group decrease and as such, the magnitude of intermolecular hydrogen bonding between the molecules also decrease accordingly. Hydrogen bonds occur between
molecules of a substance when hydrogen is covalently bonded to an electronegative element. Hydrogen bonding is responsible for the high melting and boiling points of small molecules such as water which contain the highly electronegative oxygen atom.
So, as we move down the group there is lesser intermolecular hydrogen bonding between the hydride molecules of group 6A elements resulting in the observed trend in melting and boiling points of the hydrides.
The weaker hydrogen bonds that occurbetween molecules of group 6A hydrides lead to a steady decrease in melting and boiling points of the hydrides of group 6A elements as we move down the group.
list some applications of chemistry in your dail life
Chemistry and chemical reactions are not just limited to the laboratories but also the world around you.
Chemistry in Food Production:
Plants produce food for themselves through photosynthesis; which is a complex chemical reaction in itself. The chemical reaction that takes place in photosynthesis is the most common and vital chemical reaction.
6 CO2 + 6 H2O + light → C 6H12O6 + 6 O2
Chemistry in Hygiene:
Right before you consume your food, you make it a point to wash your hands with soap. Isn’t it? The cleaning action of soap is based on its ability to act as an emulsifying agent. Soaps are fatty acids salts of sodium or potassium; produced by a chemical reaction called saponification. Soaps interact with the grease or oil molecule, which, in turn, results in a cleaner surface.
The Chemistry of an Onion:
Ever wondered why you shed tears while chopping an onion? This also happens because of the underlying chemistry concepts. As soon as you slice an onion, sulfenic acid is formed from amino acid sulfoxides. Sulfenic acid is responsible for the volatile gas, propanethiol S-oxide, that stimulates the production of tears in the eyes.
Chemistry in Baking:
Who does not like to eat fluffy freshly baked bread? Baking soda is an efficient leavening agent. The addition of baking soda to food items before cooking leads to the production of carbon dioxide (CO2); which causes the foods to rise. This whole process of rising of baked good is called chemical leavening.
Chemistry in Food Preservatives:
In case you ever read the ingredients on the bottle of ketchup, jams or pickles, you might be surprised to see a never-ending list of chemicals. What are they? These chemicals are called food preservatives; which delay the growth of microorganisms in foods. The chemical food preservatives not only prohibit the growth of bacteria, virus, fungi but also hinder the oxidation of fats, which is responsible for making the foods rancid. The most common chemical food preservatives are sodium benzoate, sorbic acid, potassium sorbate, calcium sorbate, sodium sorbate, propionic acid, and the salts of nitrous acid.
Chemistry in Digestion
The moment you put food in your mouth, a number of different chemical reactions start in your digestive tract. Saliva contains the enzyme amylase, which is responsible for breaking down carbohydrates, the stomach starts producing hydrochloric acid, the liver releases bile and the list of compounds released during digestion goes on. How do they work? All these enzymes undergo chemical reactions so that proper digestion, as well as assimilation of the food, occurs.
The Working of a Sunscreen
Before going out on a sunny day, you make it a point to wear sunscreen. Even the principle, behind the working of a sunscreen, has a chemistry background. The sunscreen uses a combination of organic and inorganic compounds to act as a filter for incoming ultraviolet rays. Sunblocks, on the other hand, scatter away UV light; so that it is unable to penetrate deep into the skin. Sunblocks contain complex chemical compounds like zinc oxide or titanium oxide, which prevent the UV rays to invade deeper into the skin.
Chemistry in Rust Formation
With time, your iron instruments start developing an orange-brown flaky coating called rust. The rusting of iron is a type of oxidation reaction. The atoms in the metal iron undergo oxidation and reduction; causing rusting. The formation of verdigris on copper and the tarnishing of silver are also the other everyday examples of chemical reactions. The chemical equation underlying rusting is:
Fe + O2 + H2O → Fe2O3. XH2O
Hope it helps.
Which best illustrates the way in which radiation transfers thermal energy?
O
Warr
Cool
o
Warm
Cool
Warm
Cool
Warm
H11
Cool
Answer:
It is so because heat is flowing from hot body to cold body, and there is no direct contact between the body. It explains correctly the mode of transmission of thermal energy through the process of radiations.
Explanation:
Fun fact:
How does thermal energy transfer by radiation?
Radiation. All objects transfer energy to their surroundings by infrared radiation . The hotter an object is, the more infrared radiation it gives off. No particles are involved in radiation, unlike conduction.
5 compounds that has electrovalent and covalent bond
Answer:
electrovalent
NaCl
Lithium Carbonate
ammonium phosphate
aluminium floride
potassium hydride
covalent
methane
benzene
carbon iv oxide
hydro flouride
hydro chloride
What mass of octane (in g) is required to produce 8210 kJ of heat?
Answer:
184.8 g
Explanation:
Step 1: Write the balanced thermochemical equation
C₈H₁₈(l) + 25/2 O₂(g) ⇒ 8 CO₂(g) + 9 H₂O(g) ΔH°rxn = -5074.1 kJ
Step 2: Calculate the moles of octane required to produce 8210 kJ of heat
According to the thermochemical equation, 5074.1 kJ of heat are released per mole of octane consumed.
-8210 kJ × 1 mol C₈H₁₈/(-5074.1 kJ) = 1.618 mol
Step 3: Calculate the mass corresponding to 1.618 moles of octane
The molar mass of C₈H₁₈ is 114.23 g/mol.
1.618 mol × 114.23 g/mol = 184.8 g
1mol produces=5074.1KJ heat .
Moles produce 8210 KJ heat :-
8210/5074.1=1.62molMolar mass of Octane :-
8(12)+18=96+18=114g/molMass of Octane=
1.62(114)=184.7gWhich state of matter is characterized by having an indefinite shape, but a definite volume?
solid
gas
liquid
Answer:
liquid is the right answer k
Answer:
liquid
Explanation:
What would happen to the pressure of a closed sample of gas whose temperature increased while its volume decreased? Explain your reasoning in terms of the kinetic molecular theory of gases.
Answer:
As the temperature increases, the average kinetic energy increases as does the velocity of the gas particles hitting the walls of the container. The force exerted by the particles per unit of area on the container is the pressure, so as the temperature increases the pressure must also increase.
I hope this will help you if not soo sorry :)
2 . a) b) (1) List three oxides of nitrogen ( 3ks) State Charles law (2mks) (111) A given mass of gas occupies 300cm at 900mmHg if temperature remains constant (5mks) State one industrial application in each of the following Crystallization (2mks) (11) Filtration (2mks) (111) Fractional distillation (2mks) (1) State the property of hydrogen which makes it suitable for filling meteorological balloons (2mks) Why is helium preferred to hydrogen in filling balloons? (2mks) (1) с) 3. a) b) (1) List the steps involved in the purification of water for town supply State two differences between rusting and burning (1) Copy and complete the following table Element No of neutron Electron Group configuration 1 1522522p5 ZOR (ii) State the family to which the elements belong State the two differences between fine chemical and heavy chemicals 32P 130 19 c) 1. a ( List the three types of particles present in an atom Name the element that does not contain all the three particles What is the particle that is not present What is isomerism? b)
ask correctly so that your points cant make fun of others
Which event is an example of melting?
A. Wax drips down the side of a lit candle.
B. Perspiration dries on a person's skin.
C. Rain turns to ice pellets.
D. A mirror fogs up when someone takes a hot shower.
I’m just curious tbh
Answer:
A. Wax drips down the side of a lot candle.
Explanation:
The chemical change from solid to liquid. This is a combustion reaction, so carbon dioxide gas and water vapour is also produced but you can't see them
Answer:
A. Wax drips down the side of a lot candle.
Explanation:
Complete the following road map for converting volume of A to volume of B for a titration of aqueous solution A with aqueous solution B.
a. multiply by the molarity of B
b. multiply by the moles of B per moles of A
c. divide by the molarity of B
d. multiply by the molarity of A
e. divide by the molarity of A
f. multiply by the moles of A per moles of B
1. volume A (L)
2. moles A
3. moles B
4. volume B (L)
Answer:
Explanation:
The solution of known concentration is expressed as molarity. Molarity is the mole fraction of solute (i.e. the dissolved substance) per liter of the solution, Molarity is also commonly called molar concentration.
Mathematically;
[tex]\mathtt{Molarity = \dfrac{moles \ of \ solute}{ liters \ of \ solution}}[/tex]
To copy and complete the road map from the given question, we have the following array:
Volume A (L)
↓
d. multiplied by the molarity of A
↓
moles A
↓
b. multiplied by the moles of B / moles of A
↓
moles B
↓
c. divided by the molarity of B
↓
volume B (L)
Arrange the forms of electromagnetic radiation in order of decreasing energy (from highest energy to lowest energy). You are currently in a ranking module. Turn off browse mode or quick nav, Tab to move, Space or Enter to pick up, Tab to move items between bins, Arrow Keys to change the order of items, Space or Enter to drop.
highest energy lowest energy
radio waves
x rays
gamma rays
infrared
microwaves
ultraviolet
visible
Answer:
gamma rays > X-rays > ultraviolet radiation > visible light > infrared > radio waves.
Explanation:
Electromagnetic waves are those waves that require no material medium for propagation. They can travel through space and they all move at the speed of light.
Electromagnetic waves are composed of both electric and magnetic fields which are mutually at right angles to each other.
The order of decreasing energy of electromagnetic waves is;
gamma rays > X-rays > ultraviolet radiation > visible light > infrared > radio waves.
How many moles of water are produced if 3.30 moles of N20 is
produced? NH4NO3 --> N20 + 2 H2O (mole to mole conversion) 1 step
Answer:
The netto reaction equation is:
2 OH- + 2H+ = 2 H2O
So the answer is 2 moles.
A solution has a [H3O+] of 1 × 10−5 M. What is the [OH−] of the solution?
A) 9 M
B) 14 M
C) 1 x 10^{-9}
D) 1 x 10^{-14}
PLZZZZZZZZ HELPPPPPP
Answer:
482
Explanation:
Using the following equation how many grams of water you would get from 886 g of glucose:
C6H12O6 + 6O2 → 6CO2 + 6H2O + energy
Answer:
531.6g
Explanation:
Total moles of glucose in this case is: 886/180= 4.922 (mole)
For every 1 mole glucose we get 6 mole water
-> Mole of water is: 4.922 * 6= 29.533 (mole)
weight of water is 18. Therefore, total weight of water that we will have from 886g of glucose are: 25.933*18= 531.6g
Which of the following is true about oxidation-reduction reactions?
=============================================================
One atom is oxidized and one is reduced
Both atoms are oxidized and reduced
The total number of electrons changes
One atom can be oxidized without one being reduced
Answer:
the last one probably
Explanation:
Consider the following events that take place when rip currents occur.
A. Waves travel to the beach.
B. Waves are trapped by the sandbars.
C. Waves reach the shore and go back to the ocean.
D. Waves speed up and flow between the sandbars.
E. Waves are broken by the sandbars.
Which list shows the order of events in the production of rip currents?
heating, the particle _______________ increases as more __________ __________ is added
Answer: what are the choices?!.
Explanation:
Which of the following is not generally a characteristic of metal?
Ductility
O
Malleability
High melting point
Low boiling point
Exercise 2: (7 points)
Augmentin
Augmentin is a drug formed by amoxicillin of molecular formula C16H19N3O5S.3H20 and molar mass 419 g.mol"! Augmenting is used to treat infections caused by certain bacteria. The normal dose is 500mg of tablet each 12 hours. The maximum dose is 40g of Augmentin for 10 days. Augmentin generally has a normal action; a high dose (overdose) in Augmentin causes kidney problems.
1) Explain in which case we use Augmentin. 2) 2.1) Il a patients dissolved in the water an Augmentin tablet of 500mg to prepare a 100ml solution, determine the mass concentration and molar concentration of the obtained solution 2.2) Write the procedures followed to prepare this solution and indicate the materials used in this preparation.
3) If a patient takes daily 100ml of Augmentin solution of concentration 50g L for 10 days, will he suffer from kidney problems?
Answer:
See explanation
Explanation:
I) from the question;
500 × 10^-3 g dissolves in 100ml
xg dissolves in 1000ml
x = 500 × 10^-3 g × 1000ml/100 ml
x= 5 g/L
Mass concentration = molar concentration × molar mass
Molar concentration = Mass concentration/ molar mass
Molar concentration = 5g/L/419 g/mol
Molar concentration = 0.0119 M
ii) To prepare this solution, measure out 500mg with a weighing balance. Transfer the solid to a standard 100 ml volumetric flask. Make up to the 100ml mark with distilled water.
iii) mass concentration of the solution = 50 g/L
Volume of the solution= 100 ml
Mass of the solid = 50 g/L × 100/1000 L
Mass of solid = 5g
This 5g was taken for 10 days, hence a total of 50 g
Since the normal dose of the drug is 40g for ten days, the patient will suffer from kidney problems because he/she has taken the drug above the recommended dosage.
A penny has a thickness of approximately 1.0 mm. If you stacked Avogadro's number of pennies one on top of the other on Earth's surface, how far would the stack extend (in kilometers). For comparison, the sun is about 150 million km from Earth and the nearest star (Proxima Centauri) is about 40 trillion km from Earth].
Answer:
6.02 × 10²⁷ km
Explanation:
Step 1: Calculate the height of the stack of pennies
A penny has a thickness of approximately 1.0 mm. If you stacked Avogadro's number of pennies (6.02 × 10²³ pennies) one on top of the other on Earth's surface, the height of the stack of pennies would be:
6.02 × 10²³ pennie × 1.0 mm/1 pennie = 6.02 × 10²³ mm
Step 2: Convert 6.02 × 10²³ mm to kilometers
We will use the following conversion factors.
1 km = 10³ m1 m = 10³ mm6.02 × 10²³ mm × 1 m/10³ mm × 1 km/10³ m = 6.02 × 10²⁷ km
A crop is sprayed with a pesticide to prevent infestation and damage from insects. However, the next season the same pesticide fails to prevent the insects from damaging the crop. Why
Answer:
Farmers spray to mitigate crop damage caused by pests. A pest is any biological organism, including weeds, pathogens, and arthropods, that interferes with the production of crops affecting quality and/or yield. ... Pesticides work in many different ways by affecting their target, whether it be a weed, pest, or disease.
Explanation:
this is my answer❤︎
Identify the bronsted-lowry acid and the bronsted-lowry base in this reaction on the left side of each of the following equations, and also identify the conjugate acid and conjugate base of each on the right side.
mathrm { NH } _ { 4 } ^ { + } ( a q ) + mathrm { CN } ^ { - } ( a q ) rightleftharpoons mathrm { HCN } ( a q ) + mathrm { NH } _ { 3 } ( a q )
Answer: [tex]NH_4^+[/tex] is an acid, [tex]CN^-[/tex] is a base, [tex]NH_3[/tex] is conjugate base and [tex]HCN[/tex] is conjugate acid
Explanation:
According to Bronsted and Lowry's theory:
An acid is defined as a proton donor while a base is defined as a proton acceptor.
In a chemical reaction, an acid loses a proton to form a conjugate base while a base accepts a proton to form conjugate acid.
For the given chemical reaction:
[tex]NH_4^+(aq)+CN^-(aq)\rightleftharpoons HCN(aq)+NH_3(aq)[/tex]
[tex]NH_4^+[/tex] is losing a proton thus it is an acid to form [tex]NH_3[/tex] which is its conjugate base
[tex]CN^-[/tex] is gaining a proton thus it is a base to form [tex]HCN[/tex] which is its conjugate acid
Hence, [tex]NH_4^+[/tex] is an acid, [tex]CN^-[/tex] is a base, [tex]NH_3[/tex] is conjugate base and [tex]HCN[/tex] is conjugate acid
Rita determined the experimental van 't Hoff factor, i, for KCl to be 1.9 which is less than the theoretical value of 2. Select the option that best explains the difference between the theoretical and experimental i.a) The difference is due to the ion-pairing effect which effectively reduces the number of solute particles present in the solution.b) The difference is due to the ion-pairing effect which effectively increases the number of solute particles present in the solution correct amount of KCl that will give better agreement between the experimental and theoretical results.c) Rita did not freeze the entire sample.
Answer:
The difference is due to the ion-pairing effect which effectively reduces the number of solute particles present in the solution.
Explanation:
Colligative properties are those properties that depend on the amount of solute present. Such properties include; boiling point elevation, freezing point depression etc.
Ion pairing causes the Van't Hoff factor to deviate from whole numbers. Ion pairing effect generally reduces the number of solute particles in solution thereby decreasing the experimental value of the Van't Hoff factor (i).
Hence, the reason why Rita determined the Van't Hoff factor as 1.9 and not the theoretical value of 2 is because of on-pairing effect which effectively reduces the number of solute particles present in the solution.
The difference between the theoretical and experimental is A. The difference is due to the ion-pairing effect which effectively reduces the number of solute particles present in the solution.
Colligative propertiesIt should be noted that colligative properties simply means the properties that depend on the amount of solute present.
The ion pairing causes the Van't Hoff factor to deviate from whole numbers. Therefore, they caused the difference between the theoretical and experimental values.
Learn more about ion on:
https://brainly.com/question/11638999
Help me please , I got 0.003 for a I need help with b and c
Answer:
(a) The moles of CuSO₄ is 3.125 × 10⁻³ moles.
(b) The moles of Cu is 3.125 × 10⁻³ moles.
(c) The mass of Cu is 0.2 g.
Explanation:
Given:
Mass of CuSO₄ = 0.5 g
Molar mass of CuSO₄ = 160 g/mol
The given balanced chemical equation is:
[tex]2Al+3CuSO_4\rightarrow 3Cu+Al_2(SO_4)_3[/tex]
Part (a):
Calculating the moles of CuSO₄.
[tex]\text{Moles of } CuSO_4=\frac{\text{Mass of }CuSO_4}{\text{Molar mass of }CuSO_4}\\\\\text{Moles of } CuSO_4=\frac{0.5g}{160g/mol}\\\\\text{Moles of } CuSO_4=3.125\times 10^{-3}mol[/tex]
Thus, the moles of CuSO₄ is 3.125 × 10⁻³ moles.
Part (b):
Calculating the moles of Cu.
From the balanced chemical equation, we conclude that:
As, 3 moles of CuSO₄ reacts to give 3 moles of Cu
So, 3.125 × 10⁻³ moles of CuSO₄ reacts to give 3.125 × 10⁻³ moles of Cu
Thus, the moles of Cu is 3.125 × 10⁻³ moles.
Part (c):
Calculating the mass of Cu.
Mass of Cu = Moles of Cu × Molar mass of Cu
Molar mass of Cu = 64 g/mol
Mass of Cu = (3.125 × 10⁻³ mole) × (64 g/mol)
Mass of Cu = 0.2 g
Thus, the mass of Cu is 0.2 g.
name hydrogen ion
what the symbolotom
Answer:
H+
Explanation:
it's H+
as you see hydrogen ion it could H+
A mixture of coarse sand and sugar is 45.0 percent sand by mass. 120.0 grams (g) of the mixture is placed in a fine-mesh cloth bag and dunked repeatedly in Lake Michigan. After drying, the mass of the contents of the bag equals: ________.
A. 66.0 g
B. 120.0 g
C. 65.0 g
D. 72.00 g
E. 54.0 g
Answer:
Option E
Explanation:
From the question we are told that:
Amount of sand in percentage [tex]s_p=45%[/tex]
Sample size[tex]n=120g[/tex]
Note:After being dumped in the river repeatedly the sugar melts away leaving behind the insoluble sand
Generally the equation for Amount of sand content is mathematically given by
[tex]X=n*s_p[/tex]
[tex]X=120*\frac{45}{100}[/tex]
[tex]X=54g[/tex]
Therefore
After drying, the mass of the contents of the bag equals
[tex]X=54g[/tex]
Option E
What is the pCu of the resulting solution if 20.00 mL of 0.08 M EDTA (H4Y) is added to 15.00 mL of 0.10 M CuSO4 and buffered at pH 10? The Kf’ for complex CuY2- is 2.21 x 1018
Answer:
The answer is "5.4".
Explanation:
[tex]BoH + HCL =BCL +H_2o \\\\At eq \\\\N_1V_1=N_2V_2 \\\\v_2=20 \ ml\\\\[BCL]=\frac{20 \times 0.08}{20+20}=0.04\\\\pH = \frac{1}{2} [pkw - pk_b - \log e]\\\\pk_b = 2 pH - Pkw + \Log C\\\\pK_b=5.4[/tex]
12.0: A
Mention three body fluids that are alkaline in nature
