Answer:
B
Explanation:
If the half life of a first order reaction is 24 days. Calculate the rate constant for the reaction
Answer:
Half-lives of first order reactions
[A]1/2[A]o=12=e−kt1/2.
ln0.5=−kt.
t1/2=ln2k≈0.693k.
A solution contains one or more of the following ions: Ag+, Ca2+, and Fe2+. When sodium chloride is added to the solution, no precipitate forms. When sodium sulfate is added to the solution, a white precipitate forms. Then, the precipitate is filtered off and sodium carbonate is added to the remaining solution, and a precipitate forms.
Which of the ions were present in the original solution?
Write net ionic equations for the formation of each of the precipitates observed.
Explanation:
when NaSO4 added, Ca2+ + SO42- = CaSO4
and Calcium sulphate is a white insoluble precipitate
when NaCO3 added, Fe2+ + CO32- = FeCO3
and it is a green precipitate
The total measure
of angles in a
triangle is 180° the triangle is?
What is the formula of the ion formed when tin achieves a stable electron configuration?
A. Sn2-
B. Sn3+
C. Sn4+
D. Sn4-
Answer:
Sn2–
Explanation:
The formula of the ion when tin achieves a stable electron configuration is Sn⁴⁺. Therefore, option (C) is correct.
What are the oxidation states of tin?Tin is a element with the atomic number 50 and the chemical symbol Sn. Tin is present in group 14 as a post-transition metal. Tin has two common oxidation states, +2 and +4. The oxidation state +4 of tin metal is somewhat more stable.
Sn⁴⁺ ion is chemically comparable to both of its neighbor germanium and lead in group 14. The electronic configuration of the tin metal is [Kr] 4d¹⁰5s²5p². It has four electrons in its valence shell so when it losses four electrons it gets configuration with fully filled subshells.
Sn²⁺ is called the stannous ion, while its compound SnCl₂ is known as stannous chloride. Sn⁴⁺ is called the stannic ion, while its compound SnCl⁴ is stannic chloride which is a volatile liquid.
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What is the energy per mole of photons, in kJ/mol, emitted by an argon ion laser which produces a green beam with a frequency of 5.83x1014 Hz?
Answer:
Energy per mole of photons = 2.31 × 10^2 KJ/mol
Explanation:
Energy, E = hf;
Where h is Planck's constant = 6.63 ×10^-34, and f is frequency of the photons.
E = 6.63 × 10^-34 × 5.8 × 10^14
E = 3.84 × 10^-22 KiloJoules
I mole of photons contains Avogadro's number of particles, 6.02 × 10^23
Therefore, the energy per mile of photon is 3.84 × 10^-22 KJ × 6.02 × 10^23
Energy per mile of photon = 2.31 × 10^2 KJ/mol
A 1 liter solution contains 0.247 M nitrous acid and 0.329 M sodium nitrite. Addition of 0.271 moles of calcium hydroxide will: (Assume that the volume does not change upon the addition of calcium hydroxide.)
a. Raise the pH slightly
b. Lower the pH slightly
c. Raise the pH by several units
d. Lower the pH by several units
e. Not change the pH
f. Exceed the buffer capacity
Answer:
a. Raise the pH slightly
Explanation:
We know that
Pka of HNO2/KNO2 =3.39
Moles of HNO2 in the buffer=0.247 mol/L×1L=0.247 moles
Moles of NO2-=0.329mol/L×1L=0.329 moles
If 0.271 moles of Ca(OH)2 is added it will neutralise 0.136 moles of acid ,HNO2,remaining HNO2=0.247-0.136=0.111 moles
Moles of NO2- will increase as 0.0333 moles Ca(NO)2 will be formed =0.0333+0.036=0.0693 moles
pH=pka+log [base]/[acid] {henderson -hasselbach equation}
=3.39+log (0.0693/0.0317)=3.39+0.34=3.73
pH=3.73
Use the drop-down menus to seled the correct responses to each question about ocean zones
In which zone do you find marshes and mangrove forests?
In vich zone are plan con plentiful, providing plenty of food for the fish that live there?
in which zone would you find very little plant or animal de compared to other zones?
Answer:
Intertidal zone
Neritic zone
Open-ocean zone
Note: the correct questions are found below;
In which zone do you find marshes and mangrove forests?
In which zone are plankton plentiful, providing plenty of food for the fish that live there?
In which zone would you find very little plant or animal life compared to other zones?
Explanation:
The intertidal zone, sometimes called the littoral zone, is the area of the marine shoreline that is exposed to air at low tide, and covered with seawater when the tide is high. Intertidal zonation refers to the tendency of plants and animals to form distinct communities between the high and low tide lines. Some microclimates in the littoral zone are moderated by local features and larger plants such as mangroves.
The neritic zone is the region of shallow water (200 meters depth) above the continental shelf where light penetrates to the sea floor.
Due to the abundant supply of sunlight and nutrients such as plankton in this zone, it is the most productive ocean zone supporting the vast majority of marine life.
The open oceans or pelagic ecosystems are the areas away from the coastal boundaries and above the seabed. It encompasses the entire water column and lies beyond the edge of the continental shelf. It extends from the tropics to the polar regions and from the sea surface to the abyssal depths.
Answer:
Intertidal zone
Neritic zone
Open-ocean zone
Explanation:
1. A 99.8 mL sample of a solution that is 12.0% KI by mass (d: 1.093 g/mL) is added to 96.7 mL of another solution that is 14.0% Pb(NO3)2 by mass (d: 1.134 g/mL). How many grams of PbI2 should form?
Pb(NO3)2(aq) + 2 KI(aq) PbI2(s) + 2 KNO3(aq)
Answer:
The mass of PbI2 will be 18.2 grams
Explanation:
Step 1: Data given
Volume solution = 99.8 mL = 0.0998 L
mass % KI = 12.0 %
Density = 1.093 g/mL
Volume of the other solution = 96.7 mL = 0.967 L
mass % of Pb(NO3)2 = 14.0 %
Density = 1.134 g/mL
Step 2: The balanced equation
Pb(NO3)2(aq) + 2 KI(aq) ⇆ PbI2(s) + 2 KNO3(aq)
Step 3: Calculate mass
Mass = density * volume
Mass KI solution = 1.093 g/mL * 99.8 mL
Mass KI solution = 109.08 grams
Mass KI solution = 109.08 grams *0.12 = 13.09 grams
Mass of Pb(NO3)2 solution = 1.134 g/mL * 96.7 mL
Mass of Pb(NO3)2 solution = 109.66 grams
Mass of Pb(NO3)2 solution = 109.66 grams * 0.14 = 15.35 grams
Step 4: Calculate moles
Moles = mass / molar mass
Moles KI = 13.09 grams / 166.0 g/mol
Moles KI = 0.0789 moles
Moles Pb(NO3)2 = 15.35 grams / 331.2 g/mol
Moles Pb(NO3)2 = 0.0463 moles
Step 5: Calculate the limiting reactant
For 1 mol Pb(NO3)2 we need 2 moles KI to produce 1 mol PbI2 and 2 moles KNO3
Ki is the limiting reactant. It will completely be consumed ( 0.0789 moles). Pb(NO3)2 is in excess. There will react 0.0789/2 = 0.03945 moles. There will remain 0.0463 - 0.03945 = 0.00685 moles
Step 6: Calculate moles PbI2
For 1 mol Pb(NO3)2 we need 2 moles KI to produce 1 mol PbI2 and 2 moles KNO3
For 0.0789 moles KI we'll have 0.0789/2 = 0.03945 moles PbI2
Step 7: Calculate mass of PbI2
Mass PbI2 = moles PbI2 * molar mass PbI2
Mass PbI2 = 0.03945 moles * 461.01 g/mol
Mass PbI2 = 18.2 grams
A _____ is a fracture or break in Earth's surface.
A FAULT is a fracture or break in Earth's surface
Based on Table I, which compound dissolves in water by an exothermic process? *
NH4NO3
NH4Cl
NaOH
NaCl
The compound whose dissolution is exothermic in the list is NaOH.
What is an exothermic reaction?An exothermic reaction is one in which heat is gven out in the process. In an exothermic reaction, the reaction vessel feels hot after the reaction is complete.
The table is not shown here. However, we know that the dissolution of NaOH in water is an exothermic process hence the answer is option C.
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Gino made a table to describe parts of the electromagnetic spectrum. A 3-column table with 4 rows. The first column labeled wave has entries ultraviolet, radio waves, infrared, x-rays. The second column labeled frequency has entries high, very low, low, high. The third column labeled Wavelength has entries long, very long, long, short. What mistake did Gino make? X-rays should have a low frequency and a long wavelength. Infrared light should have a high frequency, not a low frequency. Radio waves should have a very high frequency and a very short wavelength. Ultraviolet light should have a short wavelength, not a long wavelength.
Answer:
D. Ultraviolet light should have a short wavelength, not a long wavelength.
Explanation:
just took the quiz on Ed
The mistake Gino made is, ultraviolet light should have a short wavelength, not a long wavelength.
What is electromagnetic spectrum?Electromagnetic spectrum is the arrangement of electromagnetic radiations in the order of increasing frequency or decreasing wavelength.
Examples electromagnetic radiations based on increasing wavelength include;
Gamma rays X raysUltravoilet raysVisible lightInfrared lightMicrowavesRadio wavesThus, the mistake Gino made is, ultraviolet light should have a short wavelength, not a long wavelength.
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which statement correctly describes the transfer of energy in the food chain in the land
Answer:
The question lacks options, the options are:
A) Energy is transferred to consumers, which convert it to nitrogen and use it to make amino acid
B) Energy from producers is converted into oxygen and transformed to consumers.
C) Energy from the sun is stored by green plants and transferred to consumers.
D) Energy is transferred to consumers, which use it to produce food.
The answer is C
Explanation:
Organisms obtain energy in an ecosystem by feeding on one another in a chain called FOOD CHAIN. Energy is transferred when one organism feeds on another. A food chain always begins with a PRODUCER, which is an autotrophic organism capable of producing its own food via light energy from the sun.
In a terrestrial ecosystem, the energy a plant captures via Its Chlorophyll is used to produce food during photosynthesis. This energy is stored in the plants and transferred when a set of organisms called PRIMARY CONSUMER feeds on the plant. The transfer continues in that order till decomposers.
Whats is the difference between a strong electrolyte and a weak electrolyte
Answer:
Well, for one thing,I played football for 7 years. Gatorade wouldn't be Gatorade without electrolytes. The electrolytes in that bottle of Gatorade give you energy. Those electrolytes Are what propel you through whatever you are doing at that time. Those are what give you energy.
Explanation:
In the Bohr model of the hydrogen atom, the electron occupies distinct energy states. One transition between energy states of the hydrogen atom is represented by the picture on the left.
1. In this transition an electron moves from the n = level to the n = level.
2. Energy is_______ in this process.
A. Absorbed
B. Emitted
3. The electron moves ___________ the nucleus.
A. Closer to
B. Further from
Answer:
1. ELECTRON MOVES FROM THE n = 4 to n = 1 LEVEL
2. ENERGY IS EMITTED
3. THE ELECTRON MOVES CLOSER TO THE NUCLEUS
Explanation:
the question is incomplete as the picture is not shown but here is the picture and the solution.
Bohr model of the hydrogen atom shows that electrons would not emit energy but emit or absorb protons as it moves to a lower or higher energy levels respectively. In this question as shown in the picture below, the hydrogen atom moves from energy level 4 to energy level 1 and in such transition, energy is emitted and returns to its ground state after been excited to a higher level o n equals to 4. The energy emitted follows the law of conservation of energy. That is the amount of energy needed to excite the atom to a higher level is emitted upon transition back to the ground state.
The size of the hydrogen atom will also reduce and the electron will move closer to the nucleus. This is because as energy increases, the electron is found at a greater distance away from the nucleus and vice versa. And as the electron moves farther away the electrostatic force between it and the nucleus reduces and it is loosely held by the nucleus and vice versa, As the case of the question, the electron moves closer to the nucleus and it is strongly attached to the nucleus due to increase electrostatic attraction between it and the nucleus.
Answer:
In this transition, energy is emitted
The electron moves closer to the nucleus
Explanation:
In the Bohr's model of the atom, electrons occupy specific energy levels shown by the principal quantum number. An electron that is stationary in its orbit does not radiate energy.
However, an electron may absorb energy and be excited to higher energy levels or emit energy when descending from a higher to a lower energy level. This energy is usually observed as a photon of light of appropriate wavelength and frequency.
In the image, the electron descends from energy level n=4 to energy level n=1. Since it has moved from a higher to a lower energy level, energy is emitted. Recall that energy levels increase outwards from the nucleus. Since n=1 is closest to the nucleus, the electron has moved closer to the nucleus. Hence the answers above.
What system of units is used by only a small number of countries in the world, including the U.S.?
Answer:
The correct answer is the imperial system.
Explanation:
Only three countries in the world, that is, the United States, Myanmar, and Liberia use the imperial system. These include measurements in the form of inches, ounces, Fahrenheit, and feet. In the imperial system, the distances, height, weight, or area measurements are used eventually that traced back to everyday items or parts of the body.
In comparison to other metric systems, the units used in the imperial system are not further differentiated easily into parts of hundreds or thousands, and are thus, regarded of less use in comparison to other metric systems by some. The real follower of the imperial system at present in the world is the United States.
easy question, need help
Answer:
210 amps
Explanation:
B
When making a fire, without gas, matches, or a lighter, what are two important things about the wood?
Answer:
that is a solid and that there are other ways to make a fire?
When 177. g of alanine (C3H7NO2) are dissolved in 800.0 g of a certain mystery liquid X, the freezing point of the solution is 5.9 °C lower than the freezing point of pure X. On the other hand, when 177.0 g of potassium bromide are dissolved in the same mass of X, the freezing point of the solution is 7.2 °C lower than the freezing point of pure X. Calculate the van't Hoff factor for potassium bromide in X. Be sure your answer has a unit symbol, if necessary, and is rounded to the correct number of significant digits.
Answer:
Van't Hoff factor of KBr is 1.63
Explanation:
Freezing point depression due the addition of a solute follows the formula:
ΔT = Kf×m×i
Where ΔT is change in freezing point, Kf is freezing point depression constant of the solvent X, m is molality of the solution (mol / kg) and i is Van't Hoff factor.
Moles of 177g of alanine (Molar mass: 89.09g/mol) are:
177g × (1mol / 89.09g) = 1.99 moles. In 0.800kg:
1.99mol / 0.800kg = 2.49m
Replacing in freezing point depression formula:
5.9°C = Kf×2.49m×1
Alinine has a Van't Hoff factor of 1
The Kf of the solvent is:
2.37 °C/m
Molality of the 177.0g of KBr solution (Molar mass: 119g/mol) is:
177.0g × (1mol / 119g) = 1.487 moles / 0.800kg = 1.859m
And the freezing point depression formula is:
7.2°C = 2.37°C/m×1.859m×i
1.63 = i
Van't Hoff factor of KBr is 1.63
Which of these represents the correctly balanced equation?
HCI + Na2S - H2S + NaCl
4HCI +2Na2S - 2H2S + 4NaCl
2HCI + Na2S - H2S + 2NaCl
2HCI + Na2S - H2S + NaCl
Answer:
2HCI + Na2S ----> H2S + 2NaCl
Explanation:
For a balanced chemical equation, the number of moles of atoms on the reaction side must equal the number of moles of atoms on the product side, in accordance with the law of conservation of mass.
The correct answer is:
2HCI + Na2S ----> H2S + 2NaCl
Since it has equal number of moles of each atom on both sides of the equation: 2 atoms each of hydrogen, chlorine, and sodium on both sides of the equation as well as 1 atom of sulphur on both sides of the equation.
Which statement best describes displacement? Check all that apply
Answer:
i need help with this and the answer above is wrong
Explanation:
pls
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QUESTION: THINK CRITICALLY: Some conifers have female cones on the top half of the tree and male cones on the bottom half. Why would this arrangement of cones on a tree be important?
Answer:
The male cones appear on the trees in the spring time. The male cones are smaller than the female cones that we typically think of when we think of pine cones. These cones are softer and are only on the trees in the spring. After they release their pollen they die away and disappear.
Explanation:
The statements in the tables below are about two different chemical equilibria. The symbols have their usual meaning, for example AG Gibbs free energy of reaction and stands for the equilibrium constant. stands for the standard In each table, there may be one statement that is false because it contradicts the other three statements. If you find a false statement, check the box next to It. Otherwise, check the "no false statements box under the table. statement false? statement false? Ink>0
AH°
R<1
AG'>0
AG'>0
In > AH">TAS
no false statements
Answer:
see explaination
Explanation:
Please kindly check attachment for the step by step solution of the given problem
A measurement gave a mass of .34kg. This is the same as 340g
Answer:
Yes it is. 0.34 kg = 340 g (Kilograms and grams)
Explanation:
When we convert from kg to grams we multiply by 1000 because kilo mean 1000.
0.34*1000= 340
The Colstrip Power Plant
in Montana burns _______
releasing _______
into the air.
A. Iron; HCI
B.Carbon; base(soap)
C. Coal; H2SO4(sulfuric acid)
D. None of the above
Answer:
Coal; H2SO4(sulfuric acid)
Explanation:
Coal has been very helpful in power generation for decades. It has also become a major contributor to global warming, and has major negative effects on human health and the environment.
Coal is formed when dead plant matter submerged in swamp environments is subjected to the geological forces of heat and pressure over hundreds of millions of years. Over time, the plant matter transforms from moist, low-carbon peat, to coal, an energy- and carbon-dense black or brownish-black sedimentary rock.
There are many types of coal. Each type of coal must contain sulfur, which, when burned, releases toxic air pollution. The extent Sulfur content in a given coal sample is largely decided by the conditions under which the coal is formed. Low-sulfur coal usually develop in freshwater environments; high-sulfur coals are formed in brackish swamps.
The burning of coal releases its sulphur content as oxides of sulphur (SOx). These oxides of sulphur dissolve in rain water to form acid rain. Hence rain falling around the Colstrip power plant will contain H2SO4 resulting from the dissolution of SOx in rain droplets.
A gas occupies 10.00L at 100k and exerts a pressure of 1.71atm. What volume, in liters, will the gas occupy if the temp is increased to 290.29K and the pressure is increased to 9.70atm?
Answer:
5.12 L
Explanation:
P1V1/T1 = P2V2/T2
1.71 atm *10.0L /100 K = 9.70 atm *x/290.29 K
x = 1.71 atm *10.0L*290.29K /(100 K * 9.70 atm)= 5.12 L
As a system becomes less random, its entropy *
decreases
remains the same
increases
Answer:
decreases
Explanation:
The higher the entropy, the more unpredictable and the more random a value is, this is because entropy describes disorder of a system. If things are less random, that means they are predictable, which means they are more ordered.
A balloon with a volume of 5.0 L is filled with a gas at 760 tore. If the pressure is reduced to 389 torr without a change in temperature. What will be the volume of the balloon?
Answer:
[tex]V_2=9.97L[/tex]
Explanation:
Hello,
In this case, we can apply the Boyle's law in order to understand the pressure-volume relationship as an inversely proportional relationship:
[tex]P_1V_1=P_2V_2[/tex]
Thus, we can solve for the resulting volume at the second state as follows:
[tex]V_2=\frac{P_1V_1}{P_2}=\frac{5.0L*760torr}{389tor} \\\\V_2=9.97L[/tex]
Best regards.
1. Write the balanced chemical equation for the synthesis of magnesium phosphide from its elements, including the word “energy” as a product.
- Write the Keq expression for the reaction.
Answer:
3Mg(s) +2P(s) -------> Mg3P2(s) + energy
Keq= [Mg3P2]/[Mg]^3 [P]^2
Explanation:
The equation for the formation of magnesium phosphide from its elements is;
3Mg(s) +2P(s) -------> Mg3P2(s) + energy
Hence we can see that three moles of magnesium atoms combines with two moles of phosphorus atoms to yield one mole of magnesium phosphide. The equation written above is the balanced chemical reaction equation for the formation of the magnesium phosphide.
The equilibrium expression for the reaction K(eq) will be given by;
Keq= [Mg3P2]/[Mg]^3 [P]^2
How human health is expected to be affected by climate change?
“IN YOUR OWN WORDS”
Someone pls help me, I need the answer ASAP!!
Pure A (liq) has vapour pressure at 421 K is 80.1 kPa, and pure B (liq) is 61.2 kPa. The two substance form ideal liquid and gaseous mixtures. If the equilibrium composition of a mixture is established, in which the mole fraction of A in the vapour is 0.410, Calculate:
(a) The total pressure of the vapour.
(b) The composition of the liquid mixture.
Answer:
a) Total vapor pressure = 68.948 Kpa
b) Mole fraction of A = 41%, mole fraction of B = 59%
Explanation:
Find the given attachments.