Answer:
the element air is the most similar to oxygen in chemical. and physical properties
The enzyme provided is a stock solution which should be diluted 50-fold with 0.001M HCl immediately before use.
Enzyme :1mg/ml chymotrypsin A in 0.001M HCl
How do I work out this calculation, if I want the 5ml of the diluted enzyme?
In order to prepare a 50-fold diluted enzyme, 0.1 mL of the stock solution of the enzyme is taken and made up to 5.0 mL with 0.001M HCl.
What is dilution?Dilution is a process whereby a solution of lower concentration is prepared from one of a higher concentration.
Dilution is done by using the dilution formula below:
C1V1 = C2V2C1; Initial concentration of enzyme = 1 mg/mL
C2; Final concentration of enzyme = 1/50 mg/ml = 0.02 mg/ml
V1; Initial volume of enzyme = y
V2; Final volume = 5.0 ml
V1 = C2V2/C1
V1 = 0.02 * 5/1 = 0.1 mL
Therefore, in order to prepare a 50-fold diluted enzyme, 0.1 mL of the stock solution of the enzyme is taken and made up to 5.0 mL with 0.001M HCl.
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Question 11 of 30
During a reaction, the enthalpy of formation of an intermediate is -286
kJ/mol. During the reaction, 2 moles of the intermediate are produced. What
is the enthalpy value for this step of the reaction?
O A. -286 kJ
B. 572 kJ
OC. 286 kJ
OD. -572 kJ
By convention, the standard enthalpy of formation of all elements in their standard states are assumed to be zero. Here the enthalpy value for the intermediate formation step is -572 kJ. The correct option is D.
What is enthalpy of formation?The standard enthalpy of formation of a compound is defined as the enthalpy change accompanying the formation of one mole of the compound from its constituent elements, all the substances being in their standard states.
The symbol used to represent the standard enthalpy of formation is ΔfH⁰. The knowledge of standard enthalpies of various substances is useful for calculating the standard enthalpies of a reaction.
The overall energy difference between the reactants and products remains the same no matter how many intermediates there are in the reaction pathway.
The enthalpy value = 2 × -286 = -572 kJ
Thus the correct option is D.
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The specific heat of aluminum is approximately
0.90 J/g °C. How much heat energy would be
required to raise the temperature of a 50 g
sample of aluminum from 20 °C to 100 °C?
Answer:
3600J
Explanation:
Q = mc∆T
= 50 x 0.9 x (100 - 20)
= 3600J
Atoms are spherical in shape. Therefore, the Pt atoms in the cube cannot fill all the available space. If only 74.0 percent of the space inside the cube is taken up by Pt atoms, calculate the radius in picometers of a Pt atom. The mass of a single Pt atom is 3.240 × 10−22 g. [The volume of a sphere of radius r is (4/3) πr3. The volume of a cube is l3, where l is the length of a side. Avogadro's number is 6.022 × 1023.]
Answer:
Answer:
A)6.6×10^22atoms of Pt in the cube
B)1.4×10^-8m
Explanation:
(a) Calculate the number of Pt atoms in the cube.
an edge length of platinum (Pt) = 1.0 cm.
Then Volume= 1.0 cm×1.0 cm×1.0 cm=1cm^3
Then we have volume of the cube as 1cm^3
Given:
The density Pt = 21.45 g/cm3
the mass of a single Pt atom =3.240 x 10^-22 g
Then with 1atom of the platinum element, we can calculate the number of Pt atoms in the cube as
Density of pt/mass of a single Pt atom
=(21.45 /=3.240 x 10^-22)
=6.6×10^22atoms of Pt in the cube
B)Volume of cube V=4/3πr^3
V= 4/3 ×π×r^3
V= 4.19067r^3
r^3= V/4.19067
But volume is not total volume but just 74% of it, then With 74% of the space inside the cube is taken up by Pt atoms, then we need to find 74% of volume of the cube which is 1cm^3
74/100 ×1= 0.74cm^3
Then our new volume V is 0.74cm^3
r^3=0.74/4.19067×6.620 x 10^22
r^3=2.6674×10^-24
r= 3√2.6674×10^-24
r=1.4×10^-8m
How many protons,neutrons, and electrons does uranium 238 have
Explanation:
92 protons 92 electrons and 146 neutrons
Answer:
92 protons, 92 electrons, 146 neutrons
Explanation:
U-238 has 92 protons, 92 electrons, 146 neutrons.
The 238 is mass number talking about protons + neutrons. Uranium will always have 92 protons so the rest of the things are neutrons (146). Electrons will always equal protons if the element is neutral (no charge) and since no charge was given the numbers will match
Which activity helps some animals maintain their body temperature?
A. Breathing in carbon dioxide
B. Making sugars
C. Rolling in mud
D. Running away from danger
If the half life of Krypton is 3.16 minutes, what is the time needed for a sample of Krypton to decay so that 1/8th of its original amount remains
Answer:
.......................................
the density of 190mg of a liquid is 0.0076g/cm calculate the volume in ml
[tex]\\ \rm\Rrightarrow Density=\dfrac{Mass}{Volume}[/tex]
[tex]\\ \rm\Rrightarrow Volume=\dfrac{Mass}{Density}[/tex]
[tex]\\ \rm\Rrightarrow Volume=\dfrac{0.19}{0.0076}[/tex]
[tex]\\ \rm\Rrightarrow Volume=25cm³[/tex]
[tex]\\ \rm\Rrightarrow Volume=25mL[/tex]
Every spring has an equilibrium position. Which statements describe a spring at its equilibrium position? Check all that apply.
The spring constant is zero.
The elastic potential energy is at a maximum.
The elastic potential energy is zero.
The displacement of the spring is at a maximum.
The net force acting on the spring is zero.
The statements describe a spring at its equilibrium position is the elastic potential energy is zero, the displacement of the spring is at a maximum and the net force acting on the spring is zero.
What is the equilibrium position?
A body is in equilibrium when the sum of all forces acting on it equals zero. According to Newton's First Law, when resulting from the laws that act on a body that remains in a state of restriction or in motion in its motion, it remains uniformly null.
In this case the only statements that match the definition of equilibrium position are:
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Why would someone abuse steroids?
Answer:
Because steroids can increase strength with little effort, however this is illegal to do without medical need, and it comes with many side effects.
Explanation:
a 40 g sample of water absorbs 500 calories of energy, how much did the water temp changed?
2.99 °C is the change in temperature if a 40 g sample of water absorbs 500 calories of energy.
What is specific heat capacity?The specific heat capacity is defined as the quantity of heat (J) absorbed per unit mass (kg) of the material when its temperature increases 1 K (or 1 °C), and its units are J/(kg K) or J/(kg °C).
Given data:
m = 40 g
Q = 500 J
Specific heat capacity of water = 4.18 J/g°C
Change in Temperature =?
The formula for Heat Energy is given by:
Q = mcp∆T
where: Q - Heat Energy
m - mass
cp - specific heat
∆T = change in temperature, [tex]T_2 - T_1[/tex]
Solution:
Substituting the value of m, specific heat capacity of water and Q in the formula,
500 J = (40 g)(4.18 J/g°C)(∆T)
∆T = 2.99 °C
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How many grams do 6.534e+24 molecules of phosphoric acid weigh?
Answer:
1,063 grams H₃PO₄
Explanation:
To find the mass of phosphoric acid (H₃PO₄), you should (1) convert molecules to moles (via Avogadro's number) and then (2) convert moles to grams (via molar mass from periodic table).
Molar Mass (H₃PO₄): 3(1.008 g/mol) + 30.974 g/mol + 4(15.998 g/mol)
Molar Mas (H₃PO₄): 97.99 g/mol
6.534 x 10²⁴ molecules H₃PO₄ 1 mole 97.99 g
--------------------------------------------- x ------------------------------------- x --------------
6.022 x 10²³ molecules 1 mole
= 1,063 grams H₃PO₄
What does a negative AH for a molecule mean?
A. Energy was released when the molecule was formed from its
elements.
B. Energy was added when the molecule was formed from its
elements.
C. Energy was added when the molecule changed phases.
D. Energy was released when the molecule went through a phase
change.
A negative enthalpy (ΔH)for a molecule means energy was released when the molecule went through a phase change.
What is change in enthalpy (ΔH)?The enthalpy change of a reaction is the amount of heat absorbed or released as the reaction takes place.
Also, the amount of energy required to change the phase of a material is known as the enthalpy,
A negative enthalpy entails the amount of energy released during an exothermic reaction.
Thus, a negative enthalpy (ΔH)for a molecule means energy was released when the molecule went through a phase change.
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Which of these is NOT true about electromagnets?
They are permanent.
Increasing the battery makes them stronger.
They need a battery or other source of current.
Increasing the number of coils makes them stronger.
Answer:
Permanent = false
Explanation:
All of the other choices are true
Please help.
Which organic product is formed in the reaction shown in the diagram?
The organic product formed in the reaction shown in the image would be bromoethane.
Substitution reaction in alkanesAlkanes, such as ethane undergoes a substitution reaction with halogens such as bromine to produce haloethanes.
For example, the equation of the reaction between ethane and bromine water is as below:
[tex]C_2H_6 + Br_2 --- > C_2H_5Br + HBr[/tex]
The products formed are bromoethane and hydrobromic acid.
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1. Related to the number of particles in a gram of
substance and to possible motions of the
particles (2 words)
Answer:
Avogadro's number or Avogardro’s constant
Explanation:
I’m pretty sure this is correct if it’s not I’m sorry lol.
Which of these is a benefit of including comments in your code
makes the app run faster
O helps other programmers understand your code
O improves the user interface
O makes your app more user friendly
A benefit of including comments in your code is that it helps other programmers understand your code.
What is a Code?These are numbers and letters which are used to identify a particular thing at a point in time.
Comments can be put in a code so as to enable others know and understand real intentions about it etc.
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Answer: O helps other programmers understand your code
Explanation: got it right on edgen
Which of the following shows the wavelengths of light that an atom gives off when an electron falls to a lower energy level?
O A. Absorption spectrum
O B. Quantum spectrum
O C. Electromagnetic spectrum
O D. Emission spectrum
The wavelengths of light that an atom gives off when an electron falls to a lower energy level corresponds to Emission spectrum , Option D is the correct answer.
What is Emission Spectrum ?
Light is absorbed or emitted when an electron jumps or falls into an energy level.
The energy of light absorbed or emitted is equal to the difference between the energy of the orbits.
Therefore , the wavelengths of light that an atom gives off when an electron falls to a lower energy level corresponds to Emission spectrum.
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What volume of 12M HCI is needed to prepare 250
of 0.20M HCI?
Answer: 4.2
Explanation:
[tex]M_{A}V_{A}=M_{B}V_{B}\\(12)V_{A}=(250)(0.20)\\V_{A}=\frac{(250)(0.20)}{12}=\boxed{4.2}[/tex]
How do the valence electrons of an atom affect chemical reactions?
Answer:
Electrons of an atom can affect chemical reactions, because electrons have a negative charge, which can introduce a form of energy.
Which law states that at constant temperature the pressure of a given amount of gas is inversely proportional to the volume of the gas?
A.
Combined gas law
B.
Gay-Lussac’s law
C.
Charles’s law
D.
Boyle’s law
E.
Ideal gas law
Boyle’s law states that at constant temperature the pressure of a given amount of gas is inversely proportional to the volume of the gas. Hence, option D is correct.
What is Boyle’s law?The volume of a gas at a constant temperature varies inversely with the pressure exerted on it.
Boyle's law states " The pressure of a gas is inversely proportional to the volume occupied by the gas when the temperature(in kelvins) is held constant ".
[tex]P[/tex] ∝ [tex]\frac{1}{V}[/tex]
[tex]PV =CONSTANT[/tex]
This means that with an increase in the volume of gas the pressure exerted by the gas decreases or vice versa. Here variables were pressure and volume.
[tex]P[/tex] ∝ [tex]\frac{1}{V}[/tex]
Boyle’s law states that at constant temperature the pressure of a given amount of gas is inversely proportional to the volume of the gas. Hence, option D is correct.
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How many grams of KNO3 are required to prepare 0.250 L of 0.70 M solution?
Answer:
about 3
Explanation:
just did this for the points just being honiest
(5 pts) Calculating Heat from Thermochemical Equations
The thermochemical equation for the combustion of methane gas is:
Calculate much heat is released when 3.5 moles of methane gas undergo a combustion reaction.
The heat that is released by the combustion of 3.5 moles of methane is 3115 kJ/mol.
What is a thermochemical equation?A thermochemical equation is a reaction equation that incorporates the amount of heat lost/gained.
In this case, the reaction equation is; CH4 + O2 ----->CO2 + 2H2O dH = -890 kJ/mol
If 1 mole of methane releases 890 kJ/mol
3.5 moles of methane will release 3.5 moles * 890 kJ/mol/1 mole
= 3115 kJ/mol
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What is known about a reaction with a positive enthalpy?
A. Heat is given off as a product of the reaction.
B. The reaction has a large activation energy.
OC. Heat is required to make the reaction occur.
OD. The reaction will never be spontaneous.
Answer: C
Explanation:
In endothermic reactions, enthalpy is positive, and in exothermic reactions, enthalpy is negative, So, if enthalpy is positive, then it is an endothermic reaction, and hence is required for the reaction to occur.
HCl + Fe + ____ + H²
Simple Way.
Hydrochloric acid + iron --> ______ + hydrogen gas.
• Answer this question, only if you know.
• Misuse of points will cost a report.
Answer:
This is a correct answer. 2HCL + Fe = FeCl2 + H2
with strong heating calcium carbonate undergoes thermal decomposition how many mole of CaCO3 are there in 50g of calcium carbonate
Answer:
a)CaCO 3→CaO+CO 2CaCO3→CaO+CO2
b) Moles of CaCO3=4.37moles
c) I) Mass of calcium oxide =28g
ii)Mass of carbon dioxide=16.7g
iii)Volume=203cm3
URGENT HELP NEEDED!!! SPACE
Record your observation statements from Space Academy.
When the mass of the sun is larger, Earth moves around the sun at a faster (faster, slower) pace.
When the mass of the sun is smaller, Earth moves around the sun at a slower (faster, slower) pace.
When Earth is closer to the sun, its orbit becomes faster (faster, slower).
When Earth is farther from the sun, its orbit becomes slower (faster, slower).
For each trial, record the orbit number of each planet from the sun. Be sure to indicate the number of planets in the habitable zone after each trial. Create a different configuration of planets for each trial. An example has been supplied for you.
Orbit Number
Planet One Orbit Number
Planet Two Orbit Number
Planet Three Orbit Number
Planet Four Number of planets in the habitable zone Number of planets left in successful orbit
Example: sun's mass 1x
1
3
5
6
1
2
sun's mass 1x—Trial One
1
5
2
3
1
1
sun's mass 1x—Trial Two
1
2
0
0
2
2
sun's mass 2x—Trial One
1
0
0
0
1
0
sun's mass 2x—Trial Two
1
3
2
0
4
0
sun's mass 3x—Trial One
1
2
0
0
2
0
sun's mass 3x—Trial Two
1
0
0
0
1
3
Conclusion:
Your conclusion will include a summary of the lab results and an interpretation of the results. Please answer all questions in complete sentences using your own words.
Using two to three sentences, summarize what you investigated and observed in this lab.
You completed three terra forming trials. Describe the how the sun's mass affects planets in a solar system. Use data you recorded to support your conclusions.
In this simulation, the masses of the planets were all the same. Do you think if the masses of the planets were different, it would affect the results? Why or why not?
How does this simulation demonstrate the law of universal gravitation?
It is the year 2085, and the world population has grown at an alarming rate. As a space explorer, you have been sent on a terraforming mission into space. Your mission to search for a habitable planet for humans to colonize in addition to planet Earth. You found a planet you believe would be habitable, and now need to report back your findings. Describe the new planet, and why it would be perfect for maintaining human life.
The new planet is suitable for human life because it is similar to planet earth.
Describe the new planet, and why it would be perfect for maintaining human life?
The new planet has similar atmosphere just like the earth's atmosphere. It has large amount of vegetation that can hold large amount of animals. It is suitable for growing for different crops that provide food to humans.
So we can conclude that the new planet is suitable for human life because it is similar to planet earth.
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3) The following reaction produces chlorine molecules:
Energy + HCl (g) + CINO3 (8) Cl₂ (8) + HNO3 (8)
a) Describe 4 ways you could increase the concentration of chlorine molecules.
b) How would cooling shift the equilibrium of this reaction?
The 4 ways to increase the concentration of chlorine molecules is listed below and the reaction will go into reverse if cooled.
What is Le Châtelier’s principle ?
Le Châtelier's principle states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change to reestablish an equilibrium.
Energy + HCl (g) + ClNO₃ ⇄ Cl₂ + HNO₃
a. So in this reaction when at equilibrium , To increase the concentration of Chlorine molecules
1. An increase in Temperature will favour the formation of Chlorine molecules.
2. Decrease in concentration of Chlorine , or partial removal of Chlorine will result the equation to go in forward direction.
3.An Increase in the concentration of HCl will favour formation of Chlorine molecules.
4.An Increase in the concentration of CINO₃ will also favour formation of Chlorine molecules.
b. The cooling would shift the reaction into backward direction as it is an endothermic reaction in forward state.
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Which term is used to describe all the habitats around the world?
Ecosystem diversity
Genetic diversity
Natural selection
Species diversity
Answer:
ecosystem diversity
Explanation:
hope this helped
FLAG A nurse is preparing to administer morphine 0.05 mg/kg intermittent IV bolus to a newborn who weighs 3 kg. Available is morphine 0.5 mg/mL injection. How many mL should the nurse administer? (Round the answer to the nearest tenth. Use a leading zero if it applies. Do not use a trailing zero.)
The quantity of morphine, the nurse should administer is 0.3 ml.
What is morphine?Morphine is a drug which comes under the pain relieving drugs.
The quantity of morphine is 0.05 mg/kg
The weight of the baby is 3 kg.
Available morphine is 0.5 mg/mL.
0.05 x 3 = 0.15 mg
then, 0.15 mg / 0.5 = 0.3
Thus, the quantity of morphine, the nurse should administer is 0.3 ml.
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