Answer:
Energy is passed up a food chain or web from lower to higher trophic levels.
Explanation:
However, generally only about 10 percent of the energy at one level is available to the next level. This is represented by the ecological pyramid in Figure below.
Answer:
generally only about 10 percent of the energy at one level is available to the next level
Explanation:
thank you
A 45 min tape plays at the speed of 1.88 in/s. How long is the tape in meters?
One inch is equal to 2.54 cm.
Answer: 128.93m
Explanation:
We are told that a 45 min tape plays at the speed of 1.88 in/s. First we need to convert 45 mins to seconds. This will be: = 45 × 60 = 2700 seconds.
Therefore, the tape will use:
= 2700 × 1.88inch
= 5076 inch
Since 1 inch = 2.54cm
5076 inch = 2.54 × 5076 = 12893.04cm
Note that 100cm = 1m
We will then convert 12893.04cm to m. This will be:
= 12893.04cm / 100cm
= 128.9304m
= 128.93m
Determine the number of grams of magnesium oxide if you have 2.63 moles of magnesium oxide.
The number of grams of Magnesium oxide= 106 g
Further explanationGiven
2.63 moles of Magnesium oxide
Required
mass of Magnesium oxide
Solution
The mole is the number of particles contained in a substance
1 mol = 6.02.10²³
Moles can also be determined from the amount of substance mass and its molar mass
Mol = mass : Molar mass
Mass of Magnesium oxide(MgO, MW=40.304 g/mol) :
= mol x MW
= 2.63 x 40.304
= 106 g
The pKa of a solution is defined by the equation pKa=-log Ka
Where Ka= acid dissociation constant.
Use the rules for logarithms and exponents to solve fo Ka in terms of pKa.
Answer:
ka = 10^-pKa
or antilog-pka
The pKa of a solution is defined by the equation pKa=-log Ka. Where Ka= acid dissociation constant. By using the rules for logarithms and exponents to solve for Ka in terms of pKa, ka = 10^-pKa or antilog -pka.
What do you mean by the term dissociation constant ?The term dissociation constant is defined as the ratio of dissociated ions to the original acid or bases in the solution. For acids, the acid dissociation constant is defined as the ratio of concentration of dissociated ions to the concentration of original acid.
The equilibrium constant is a numerical representation of an acid's strength in a solution. Ka is frequently stated in mol/L units.
To make a more administrable number, chemists define the pKa value as the negative logarithm of the Ka value as follows:
pKa = -log Ka.
Thus, By using the rules for logarithms and exponents to solve for Ka in terms of pKa, ka = 10^-pKa or antilog -pka.
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atomic radius(size)______ from left to right across a period on the periodic table
Answer:
Decreases
Explanation:
How does light emitted from a neon sign differ from sunlight?
Answer:
The light from a neon light only emits certain colors, while sunlight emits all colors.
Answer:
Well the light from a neon sign contains only a certain visible colors, while sunlight contains the full spectrum of colors. Neon sign produce emission spectrum.
Notes:
When neon atoms absorb energy and release it, its atomic emission spectrum consists of several individual lines of color. It's not a continuous range of colors, as in white light.
Explain how the models valence bond theory, Crystal field theory, ligand field theory and molecular orbital theory has been used to describe the formation of bonding and special properties such as spectroscopic(color), magnetic properties( diamagnetic & paramagnetic) and geometry or structures in transition metal coordination complex with possible examples supported and illustrated with figures
Answer:
i am not sure if we are talking about the same thing but here let me try.....
Explanation:
To explain the observed behavior of transition metal complexes (such as how colors arise), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It allows us to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on the nonbonding electrons on the central metal ion in coordination complexes not on the metal-ligand bonds. Like valence bond theory, CFT tells only part of the story of the behavior of complexes. However, it tells the part that valence bond theory does not. In its pure form, CFT ignores any covalent bonding between ligands and metal ions. Both the ligand and the metal are treated as infinitesimally small point charges.
All electrons are negative, so the electrons donated from the ligands will repel the electrons of the central metal. Let us consider the behavior of the electrons in the unhybridized d orbitals in an octahedral complex. The five d orbitals consist of lobe-shaped regions and are arranged in space, In an octahedral complex, the six ligands coordinate along the axes.
To explain observed behavior of transition metal complexes a model involving electrostatic interactions between electrons from ligands and the electrons in unhybridized d orbitals of central metal atom has been developed. This electrostatic model is crystal field theory (CFT).
What are transition metals?The transition metals are defined as the elements in which atoms are present whose d-sub-shell is partially filled .Due to which they give rise to cations with an incomplete d-sub-shell.
They are also defined as the elements which are present in the d-block of the periodic table, which includes groups from three to twelve.These elements are called transition elements as they show a transition between highly electro-positive group 1 and highly electro-negative group 17 elements.
They have characteristic properties due to which they can exist in variable oxidation states , form colored complexes and have catalytic properties as well.These elements are all technologically very important.
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A chemist determines by measurements that .060 moles of nitrogen gas participate in a chemical reaction. Calculate the mass of nitrogen gas that participates. Be sure your answer has the correct number of significant digits.
Answer:
1.7 g N₂
Explanation:
In order to convert moles of nitrogen gas (N₂) to grams, we'll use its molar mass:
Molar mass of N₂ = (Atomic Mass of N)*2 = (14.00 g/mol)*2 = 28.00 g/mol0.060 mol N₂ * 28.00 g/mol = 1.68 g N₂0.060 only has two significant digits, so the reported answer should have two significant digits as well. Meaning the answer is 1.7 g.
The molar masses of four unknown gases are shown in the table. Molar Mass of Unknown GasesGas Molar Mass
A 44 g/mol
B 20 g/mol
C 30 g/mol
D 32 g/mol
Which gas is likely to have the highest rate of effusion?
Answer:
Gas B
Explanation:
because it has the lowest molar mass.
Molar Mass of Unknown Gas 20 g/mol gas is likely to have the highest rate of effusion. Option B is correct.
What is rate of effusion?The rate of effusion of a an y given gas is inversely proportional to the square root of the molar weight of the gas. The lighter the weight of a gas is, the rapidly it will effuse and the heavier the weight of the gas is, the slower one limited it will show effusion.
The effusion process of a given gas is in which a gas move from a container with the source of a hole of diameter which is smaller than the mean free path of the molecules or the molecule of gasses.
Therefore, molar Mass of Unknown Gas 20 g/mol gas is likely to have the highest rate of effusion. Option B is correct.
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According to the law of conservation of mass, how much mercury was present in the mercury (II) oxide? *
The decomposition of 74.2 g ammonium
nitrate yields how many liters of water a
0.954 atm and 387 K?
NH,NO3(s) → NO g) + 2H,O(g)
Note: Keep extra digits in any intermediate
calculations! Round to the correct number of
significant figures at the very end.
For R, use 0.08206 L atm/(mol K).
Answer:
61.75 L of water
Explanation:
We'll begin by calculating the number of mole in 74.2 g of ammonium nitrate, NH₄NO₃. This can be obtained as follow:
Mass of NH₄NO₃ = 74.2 g
Molar mass of NH₄NO₃ = 14 + (4×1) + 14 + (3×16)
= 14 + 4 + 14 + 48
= 80 g/mol
Mole of NH₄NO₃ =?
Mole = mass / molar mass
Mole of NH₄NO₃ = 74.2 / 80
Mole of NH₄NO₃ = 0.9275 mole
Next, the balanced equation for the reaction. This is illustrated below:
NH₄NO₃ —> N₂O + 2H₂O
From the balanced equation above,
1 mole of NH₄NO₃ decomposed to produce 2 moles of H₂O.
Therefore, 0.9275 mole of NH₄NO₃ will decompose to produce = (0.9275 × 2) = 1.855 moles of H₂O.
Finally, we shall determine the volume of water obtained from the reaction. This can be obtained as follow:
Pressure (P) = 0.954 atm
Temperature (T) = 387 K
Number of mole (n) of H₂O = 1.855 moles.
Gas constant (R) = 0.08206 L.atm/Kmol
Volume (V) of H₂O =?
PV = nRT
0.954 × V = 1.855 × 0.08206 × 387
Divide both side by 0.954
V = (1.855 × 0.08206 × 387) / 0.954
V = 61.75 L
Therefore, 61.75 L of water were obtained from the reaction.
In VSEPR theory, what information about the central atom do you need in
order to predict the shape of a molecule?
Answer:
Using the VSEPR theory, the electron bond pairs and lone pairs on the center atom will help us predict the shape of a molecule. The shape of a molecule is determined by the location of the nuclei and its electrons. The electrons and the nuclei settle into positions that minimize repulsion and maximize attraction.
Refer to the following unbalanced equation:
C6H14+ O2 → CO2 + H20
What mass of oxygen (O2) is required to react completely
with 25.0 g of CoH14?
Mass of Oxygen (O₂) : = 88.16 g
Further explanationGiven
Reaction(unbalanced)
C₆H₁₄+ O₂ → CO₂ + H₂0
25 g C₆H₁₄
Required
mass of oxygen (O₂)
Solution
Balanced equation
2C₆H₁₄ + 19O₂ ⇒12 CO₂ + 14 H₂O
mol C₆H₁₄ (MW=86,18 g/mol) :
= mass : MW
= 25 g : 86.18 g/mol
= 0.29
From the equation, mol ratio of C₆H₁₄ : O₂ = 2 : 19, so mol O₂ :
= 19/2 x mol C₆H₁₄
= 19/2 x 0.29
= 2.755
Mass O₂(MW=32 g/mol) :
= 2.755 x 32
= 88.16 g
4. Round off the following results to three significant figures:
a) 23.01 g
the answer should be a the the question
A student uses a magnet to move a 0.025 kg metal ball. The magnet exerts a force of 5 N, which causes the ball to begin moving. What is the acceleration of the ball when it begins to move?
Type your answer...
Answer: The acceleration of the ball is 200 m/s².
Explanation:
Force:
Force is the push or pull on an object with mass that causes it to change velocity or to accelerate.
Force represents as a vector, which means it has both magnitude and direction.
Given:
Mass of metal ball = 0.025 kg
Force = 5 N
To Find:
Acceleration, = ?
Solution:
Formula:
Answer questions based on the lab activity.
Assignment
Throughout the reflection, make sure you have a copy of the Student Guide and your data tables. Use the drop-
down menus to complete the statements.
The independent variable in Part I, the one that is intentionally manipulated, is the
The independent variable in Part II, the one that is intentionally manipulated, is the
The independent variable in Part III, the one that is intentionally manipulated, is the
The independent variable in Part IV, the one that is intentionally manipulated, is the
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>
Answer:
1- Mass and type of material
2- Type of material
3- Temperature
Answer:
1_ Mass and type of material.
2_ Type of material.
3_ Temperature
Explanation: Got it right on the test:)
Do the substances that are reactants in a chemical reaction remain the same after the reaction is complete?
Which of the following processes will determine the number of atoms in a sample?
Dividing the mass of the sample by its molar mass
Multiplying the mass of the sample by its molar mass
Dividing the number of moles of the sample by Avogadro's number
Multiplying the number of moles of the sample by Avogadro's number
Answer:
Multiplying the number of moles of the sample by Avogadro's number
Explanation:
The process that will help determine the number of atoms in a sample is by multiplying the number of moles of the sample by Avogadro's number.
The number of moles of substance has a wide range of application in quantitative chemistry.
A mole of any substance contains the Avogadro's number of particles. The particles can be atoms, molecules, formula units, neutrons, protons, electrons etc.
So, when we have the number of moles of a substance, the number of atoms is obtained by multiplying with the Avogadro's constant.
7. How many joules of energy do I need to change 2 grams of water from 0°C solid water to 0° liquid water?
A. 0 joules
B. 334 joules
C. 167 joules
D. 668 joules
8. How many grams of water can I covert from a liquid to a gas with 6768 joules?
A. 334 grams
B. 3 grams
C. 1 gram
D. 2,256 grams
7. D. 668 joules
8. B. 3 grams
Further explanationGiven
2 grams of water
6768 joules of energy
Required
Energy
Mass of water
Solution
The heat to change the phase can be formulated :
Q = m.Lf (melting/freezing)
Q = m.Lv (vaporization/condensation)
Lf=latent heat of fusion
Lv=latent heat of vaporization
7. phase change (ice to water)⇒Heat of fusion water=334 J/g
Q = 2 g x 334 J/g
Q = 668 J
8. phase change(water to vapor)⇒heat of vaporization water=2260 J/g
6768 J = m x 2260 J/g
m = 3 g
12dm3 ethene reacts with steam to make 18.4g ethanol.find the percentage yield
% yield = 74.35
Further explanationGiven
12 dm³ ethene = 12 L
18.4 g ethanol(actual)
Required
The percentage yield
Solution
Reaction
C₂H₄(g) + H₂O(g) ⇒ C₂H₅OH(g)
Assume at STP, 1 mol gas = 22.4 L
mol ethene :
= 12 L : 22.4 L
= 0.538
From equation, mol ratio C₂H₅OH : C₂H₄ = 1 : 1, so mol C₂H₅OH = 0.538
Mass Ethanol (MW=46 g/mol) ⇒ theoretical
= 0.538 x 46
= 24.748 g
% yield = (actual/theoretical) x 100%
% yield = (18.4/24.748) x 100%
% yield = 74.35
A 100. mL sample of oxygen is heated from 320 K to 480 K at constant pressure. What is the new volume?
Answer:200ML
Explanation:from quiz ck-12
The chemical and mechanical breakdown of rock is called
A) reclamation
B) composting
C) incineration
D) continental drift
E) weathering
Answer:
Weathering
Explanation:
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When fat comes in contact with sodium hydroxide, it produces soap and glycerin. Determine whether this is a physical change or a chemical change. Explain your
Answer: Chemical change
Explanation:
A physical change is defined as the change in which a change in shape, size takes place. No new substance gets formed in these reactions.
A chemical change is defined as the change in which a change in chemical composition takes place. A new substance is formed in these reactions.
Thus when fat comes in contact with sodium hydroxide to produce soap and glycerin, it is termed as a chemical change.
Janelle hikes along the beach every morning at the same time. Throughout the month, she notices the shoreline follows a pattern of receding and advancing. What causes the shoreline to follow this pattern?
tides
water cycle
chemical weathering
erosion and deposition
Answer:
Erosion and deposition
Answer:
Tides
Explanation:
just did it:)
Gaseous methane reacts with gaseous oxygen gas to produce gaseous carbon dioxide and gaseous water . What is the theoretical yield of carbon dioxide formed from the reaction of 0.64g of methane and 1.1 of oxygen gas?
The theoretical yield of Carbon dioxide : 0.544 g
Further explanationGiven
0.64 g Methane
1.1 g Oxygen gas
Required
The theoretical yield of Carbon dioxide
Solution
Reaction
CH₄ + 2O₂ → CO₂ + 2H₂O.
Find limiting reactant(mol : coefficient)
mol CH₄ (MW=16 g/mol) := mass : MW
= 0.64 : 16
= 0.04
mol : coefficient = 0.04 : 1 = 0.04
mol O₂ (MW=32 g/mol) := mass : MW
= 1.1 : 32
= 0.034
mol : coefficient = 0.034 : 2 = 0.017
O₂ as a limiting reactant(smaller)
Mol CO₂ based on mol O₂
From equation, mol ratio CO₂ : O₂ = 1 : 2 , so mol CO₂ :
= 1/2 x mol O₂
= 1/2 x 0.034
= 0.017
Mass O₂ :
= 0.017 x 32 g/mol
= 0.544 g
If the atoms in an ionic bond are not sharing electrons, what keeps the atoms together?
Answer:
Oppositely charged particles attract each other. This attractive force is often referred to as an electrostatic force. An ionic bond is the electrostatic force that holds ions together in an ionic compound.
Explanation:
Hope this helps :)
The lands of present-day Turkey were divided between Greece, __________, and France after the fall of the Ottoman Empire.
A.
the United Kingdom
B.
the United States
C.
Germany
D.
Italy
Please select the best answer from the choices provided
A
B
C
D
Answer:
D: Italy
Explanation:
Got it correct on EDG
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An amount 10.24 kcal of heat is added to a 35.0 g sample of a liquid at 25.00°C. The final temperature is 87.35°C. What is the specific heat of the substance in cal/g°C?
Answer:
45.24
Explanation:
10.24+35=25.24
A 1.0 mol sample of He(g) at 25°C is mixed with a 1.0 mol sample of Xe(g) at 50°C. Which of the following correctly predicts the changes in average kinetic energy and the average speed of the Xe(g) atoms that will occur as the mixture approaches thermal equilibrium?
Average Speed of Xe Atoms Average Kinetic Energy of Xe Atoms
(A) Will increase Will increase
(B) Will increase Will decrease
(C) Will decrease Will increase
(D) Will decrease Will decrease
Answer:
option D.
Both the average kinetic energy and the average speed of the Xe(g) atoms that will occur as the mixture approaches thermal equilibrium will decrease.
Explanation:
Kinetic Energy is simply said to be the energy of motion, that is when an object moved from one position to another the energy that it gains is called the kinetic energy. It is represented mathematically by 1/2mv². Where m is the mass of the object and v is the velocity of the object.
The average Kinetic energy is the average of all kinetic energies of a particle. The average Kinetic energy is represented mathematically by 3/2RT.
The temperature of Xe which is at 50°C is greater that the temperature of He which is at at 25°C will decrease when it reaches equilibrium after mixing. Hence, the average kinetic energy and the average speed of the Xe(g) atoms that will occur as the mixture approaches thermal equilibrium will decrease.
THE GUILDING PRINCIPLE: We have that the average speed and KE decreases with temperature and vice versa for real gases.
Answer:
both will decrease
Explanation:
Convert 18.82 L NO gas (At STP) to grams:
(Answer) grams (4 SF)
Answer:
[tex]m=25.20gNO[/tex]
Explanation:
Hello!
In this case, since the STP conditions are known as 273.15 K of temperature and 1.00 atm of pressure, we can use the ideal gas equation to compute the moles of NO gas first:
[tex]PV=nRT\\\\n=\frac{PV}{RT}=\frac{1.00atm*18.82L}{0.08206\frac{atm*L}{mol*K}*273.15K}=0.8396molNO[/tex]
Next, since the molar mass of NO is 30.01 g/mol the resulting mass in grams is:
[tex]m=0.8396 molNO*\frac{30.01gNO}{1molNO}\\\\m=25.20gNO[/tex]
Which has four significant figures.
Best regards!
Convert 3.32x1025 atoms Xe to grams:
(Answer) grams (3 SF)
Answer:
[tex]m=7.24x10^3g[/tex]
Explanation:
Hello!
In this case, since 6.00x10²³ atoms of any element is related to one mole of atoms via the Avogadro's number, and the molar mass of xenon is 131.3 g/mol, we obtain the following mass in grams of xenon:
[tex]m=3.32x10^{25}atoms*\frac{1mol}{6.022x10^{23}atoms}* \frac{131.3g}{1mol} \\\\m=7.24x10^3g[/tex]
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