Answer:
10 core electrons
Explanation:
Answer:
Magnesium has 10 core electrons
What is the name of PbS2
Answer:
Lead sulfide.
Explanation:
3.00 g of a fuel (MW = 650.0 g/mol) is combusted in a bomb calorimeter. The temperature of the calorimeter increases by 25.0 degrees Celsius. The heat capacity for the calorimeter has been determined to be 9.001kJ/C. What is the heat of reaction (in kJ/mol)?
Answer:
-4.88 × 10⁴ kJ/mol
Explanation:
Step 1: Calculate the heat gained by the calorimeter (Qcal)
We will use the following expression.
Qcal = C × ΔT
where,
C: heat capacity of the calorimeterΔT: temperature changeQcal = 9.001 kJ/°C × 25.0°C = 225 kJ
Step 2: Calculate the heat released by the fuel
According to the law of conservation of energy, the sum of the heat released by the fuel (Qf) and the heat absorbed by the calorimeter is zero.
Qf + Qcal = 0
Qf = -Qcal = -225 kJ
Step 3: Calculate the heat of reaction in kJ/mol
3.00 g of a fuel (MW = 650.0 g/mol) released 225 kJ of heat. The heat of reaction is:
-225 kJ/3.00 g × 650.0 g/mol = -4.88 × 10⁴ kJ/mol
describe one similarity and one difference between amylopectin and glycogen?
Answer: The main difference between amylopectin and glycogen is that amylopectin is an insoluble form whereas glycogen is a soluble form. The 1,4-alpha glycosidic bonds form the linear chain of both amylopectin and glycogen while 1,6-alpha glycosidic bonds form the branches.
Explanation:
does anyone know the answer to this
Ammonium phosphate is an important ingredient in many solid fertilizers. It can be made by reacting aqueous phosphoric acid with liquid ammonia. Calculate the moles of ammonium phosphate produced by the reaction of of ammonia. Be sure your answer has a unit symbol, if necessary, and round it to significant digits.
The given question is incomplete. The complete question is:
Ammonium phosphate [tex](NH_4)_3PO_4[/tex] is an important ingredient in many solid fertilizers. It can be made by reacting aqueous phosphoric acid [tex]H_3PO_4[/tex] with liquid ammonia. Calculate the moles of ammonium phosphate produced by the reaction of 1.7 mol of ammonia. Be sure your answer has a unit symbol, if necessary, and round it to the correct number of significant digits.
Answer: 0.57 moles of ammonium phosphate are produced by the reaction of 1.7 moles of liquid ammonia
Explanation:
The balanced chemical equation is:
[tex]H_3PO_4+3NH_4OH\rightarrow (NH_4)_3PO_4+3H_2O[/tex]
According to stoichiometry:
3 moles of liquid ammonia [tex](NH_4OH)[/tex] produces = 1 mole of ammonium phosphate [tex](NH_4)_3PO_4[/tex]
Thus 1.7 moles of liquid ammonia [tex](NH_4OH)[/tex] produces = [tex]\frac{1}{3}\times 1.7=0.57[/tex] mole of ammonium phosphate [tex](NH_4)_3PO_4[/tex]
Thus 0.57 moles of ammonium phosphate are produced by the reaction of 1.7 moles of liquid ammonia
3. Which of the following describes the author's purpose in the text? R1.6
A.
to encourage students not to think about money when they're
choosing a degree or career to pursue
B. to stress the importance of viewing college as a way to develop jobs
skills, as well as determine what is important to you
C. to discourage students from pursuing careers in business, as people
are generally dissatisfied with their lives
D. to encourage students to pursue careers that help other people, as
they are usually the most enjoyable and meaningful
Answer:
B
Explanation:
I took the assessment
Combustion Analysis of an unknown hydrocarbon resulted in the capture of 216.00 g of water vapor and 440.00 g of CO2. The total mass of the hydrocarbon before combustion was 144 g.
(1. How many moles of carbon dioxide are present after combustion?)
(2. What is the empirical formula for the unknown hydrocarbon?)
(3. How many water molecules does the water vapor trap capture?)
(4. The gram-formula mass for the unknown hydrocarbon was determined to be 72 g/mol. How many moles of the unknown hydrocarbon were present in the original sample?)
(5. infrared spectral analysis determines that the unknown hydrocarbon does NOT contain oxygen. How many moles of O2 are used in combusting the unknown sample?)
1: 10 mol CO2
2: C10H24
3: 12 mol H2O
4: 0.5 mol
5: 16 mol O2
The compound is C5H10.
From the information available in the question;
Number of moles of carbon dioxide = 440.00 g/44 g/mol = 10 moles
Number of moles of water vapor = 216.00 g/18 g/mol = 12 moles
Mass of carbon = 10 moles × 12 g/mol = 120 g of carbon
Moles of hydrogen = 12 moles × 2 g/mol = 24 g of hydrogen
Number of moles of carbon = 120 g/12 g/mol = 10 moles
Number of moles of hydrogen = 24 g/1 g/mol =24 moles
Divide through by the lowest number of moles =
C - 10/10 H - 24/10
C - 1 H - 2
The empirical formula is CH2
Molar mass of the compound = 72 g/mol
[12 + 2(1)]n = 72
14n = 72
n = 5
The compound is C5H10.
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A man washes clothes in a stream using a detergent that contains phosphorus. Which type of pollution is this?
Question 2 options:
toxic
sediment
nutrient
bacterial
Answer:
bacterial or toxic please
what is elimination reaction
What is the number of moles in 546 g strontium nitrite?
A. 0.388 mol
B. 2.58 mol
C. 329 mol
D. 3.04 mol
How much heat (in kJ) would need to be removed to cool 150.3 g of water from 25.60°C to -10.70°C?
Answer:
Q = -22.9 kJ
Explanation:
Given that,
Mass of water, m = 150.3 g
Water gets cool from 25.60°C to -10.70°C.
The specific heat of water, c = 4.2 J/g°C
The formula for heat needed is given by :
[tex]Q=mc\Delta T\\\\Q=150.3\times 4.2 \times (-10.7-25.6)\\\\Q=-22914.738\\\\or\\\\Q=22.9\ kJ[/tex]
So, 22.9 kJ of heat is needed to be removed to cool.
3. How many particles are present in 13.4 moles of carbon dioxide?
8.07. 1024 particles
04.49. 1022 particles
6.02. 1024 particles
6.02. 1023 particles
Answer:
[tex]\boxed {\boxed {\sf 8.07 *10^{24} \ particles}}[/tex]
Explanation:
To convert from moles to representative particles, Avogadro's number: 6.02*10²³ is used. This number tells us the amount of particles in 1 mole of a substance. We can use it as a ratio.
[tex]\frac {6.02*10^{23} \ particles}{1 \ mol \ CO_2}}[/tex]
Multiply by the given number of moles.
[tex]13.4 \ mol \ CO_2 *\frac {6.02*10^{23} \ particles}{1 \ mol \ CO_2}}[/tex]
The moles of carbon dioxide will cancel out.
[tex]13.4 *\frac {6.02*10^{23} \ particles}{1}}[/tex]
The denominator of 1 can be ignored and this becomes a simple multiplication problem.
[tex]13.4 * {6.02*10^{23} \ particles[/tex]
[tex]8.0668*10^{24} \ particles[/tex]
The original number of moles has 3 significant figures, so our answer must have the same. For the number we calculated, that is the hundredth place. The 6 in the thousandth place tells us round the 6 to a 7.
[tex]8.07 *10^{24} \ particles[/tex]
13.4 moles of carbon dioxide has approximately 8.07*10²⁴ particles.
Nickel carbonyl decomposes to form nickel and carbon monoxide, like this:
Ni(CO)4 → Ni + 4CO
At a certain temperature, a chemist finds that a 2.7L reaction vessel containing a mixture of nickel carbonyl, nickel, and carbon monoxide at equilibrium has the following composition:
Compound Amount
Ni(CO)4 0.597g
Ni 12.7g
CO 1.98g
Calculate the value of the equilibrium constant for this reaction. Round your answer to significant digits.
Answer: The value of the equilibrium constant for this reaction is [tex]2.8\times 10^{-5}[/tex]
Explanation:
To calculate the moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}[/tex]
Moles of [tex]Ni(CO)_4[/tex] = [tex]\frac{0.597g}{170.7g/mol}=0.0035moles[/tex]
Moles of [tex]Ni[/tex] = [tex]\frac{12.7g}{58.7g/mol}=0.216moles[/tex]
Moles of [tex]CO[/tex] = [tex]\frac{1.98g}{28.01g/mol}=0.071moles[/tex]
Volume of solution = 2.7 L
Equilibrium concentration of [tex]Ni(CO)_4[/tex] = [tex]\frac{0.0035mol}{2.7L}=1.29\times 10^{-3}M[/tex]
Equilibrium concentration of [tex]Ni[/tex] = [tex]\frac{0.216mol}{2.7L}=0.08M[/tex]
Equilibrium concentration of [tex]CO[/tex] = [tex]\frac{0.071mol}{2.7L}=0.026M[/tex]
The given balanced equilibrium reaction is,
[tex]Ni(CO)_4\rightleftharpoons Ni+4CO[/tex]
The expression for equilibrium constant for this reaction will be,
[tex]K_c=\frac{[Ni]^1\times [CO]^4}{[Ni(CO_4]^1}[/tex]
Now put all the given values in this expression, we get :
[tex]K_c=\frac{(0.08)^1\times (0.026)^4}{(1.29\times 10^{-3})^1}[/tex]
[tex]K_c=2.8\times 10^{-5}[/tex]
Thus the value of the equilibrium constant for this reaction is [tex]2.8\times 10^{-5}[/tex]
Which of the following would form a spontaneous reaction at 298 K?
O A. AH = 28 kJ/mol, AS = 0.109 kJ/(mol-K)
B. AH = 31 kJ/mol, AS = 0.093 kJ/(mol-K)
C. AH = 8.7 kJ/mol, AS = 0.008 kJ/(mol-K)
D. AH = 205 kJ/mol, AS = 0.210 kJ/(mol-K)
Answer:
A
∆H = 28 kJ/mol, ∆S = 0.109 kJ/(mol-k)
Explanation:
A P E X
The spontaneous reaction at 298 K is the one having
ΔH = 28 kJ/mol, ΔS = 0.109 kJ/(mol-K)
We know the formula of Gibb's free energy as-
ΔG = ΔH - TΔS
ΔG = 28 - (298 × 0.109)
ΔG = -4.48
If a reaction is spontaneous, change in Gibb's free energy is negative and change in entropy is positive.
Therefore, The spontaneous reaction at 298 K is the one having
ΔH = 28 kJ/mol, ΔS = 0.109 kJ/(mol-K)
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Which simple machine is best used to split apart an object
A. A screw
B. A lever
C. A wedge
D. A pulley
Answer:
its A screw :))) your welcome
For the reaction shown, drsw the major(s) expected product.
Answer:
2
Explanation:
Combustion of hydrocarbons such as octane (C_8H_18) produces carbon dioxide, a "greenhouse gas." Greenhouse gases in the Earth's atmosphere can trap the Sun's heat, raising the average temperature of the Earth. For this reason there has been a great deal of international discussion about whether to regulate the production of carbon dioxide.
1. Write a balanced chemical equation, including physical state symbols, for the combustion of liquid octane into gaseous carbon dioxide and gaseous water.
2. Suppose 0.330 kg of octane are burned in air at a pressure of exactly 1 atm and a temperature of 10.0 ?C. Calculate the volume of carbon dioxide gas that is produced. Round your answer to 3 significant digits.
Answer: 1. [tex]2C_8H_{18}(l)+25O_2(g)\rightarrow 16CO_2(g)+18H_2O(g)[/tex]
2. The volume of carbon dioxide gas that is produced is 537 L
Explanation:
1. Combustion is defined as the type of chemical reaction where a hydrocarbon is combusted in the presence of oxygen to give carbon dioxide and water.
The balanced reaction for combustion of octane is:
[tex]2C_8H_{18}(l)+25O_2(g)\rightarrow 16CO_2(g)+18H_2O(g)[/tex]
2.
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex] [tex]\text{Moles of octane}=\frac{0.330\times 1000g}{114.23g/mol}=2.89moles[/tex]
According to stoichiometry:
2 moles of octane produce = 16 moles of carbon dioxide
2.89 moles of octane produce = [tex]\frac{16}{2}\times 2.89=23.1moles[/tex] of carbon dioxide
According to ideal gas equation:
[tex]PV=nRT[/tex]
P = pressure of gas = 1 atm
V = Volume of gas = ?
n = number of moles = 23.1
R = gas constant =[tex]0.0821Latm/Kmol[/tex]
T =temperature =[tex]10.0^0C=(10+273)K=283K[/tex]
[tex]V=\frac{nRT}{P}[/tex]
[tex]V=\frac{23.1\times 0.0821Latm/K mol\times 283K}{1atm}=537L[/tex]
Thus the volume of carbon dioxide gas that is produced is 537 L
What is the correct sequence of chemical transformations with the correct phases?
Answer:
1. Cu(s) 2. Cu(NO3)2 (aq) 3. Cu(OH)2 (s) 4. CuO (s) 5. CuSO4 (aq) 6. Cu(s)
Explanation:
If Jonathan went skateboarding from 4:00 PM to 4:30 PM and traveled 450 meters, what was his average speed?
Consider this chemical equation:
2AgNO3(aq) + Cu(s) → Cu(NO3)2(aq) + 2Ag(s)
Which substances dissolve in solution? Select all
that apply.
AgNO3
Cu
Cu(NO3)2
Ag
Answer is:AgNO3 and Cu(NO3)2
Answer:
the answer is very correct as AgNO3 and Cu(NO3)2
Answer:
A,C
Explanation:
the person above me is correct
Listed below are characteristics that serve as evidence of shared ancestry between fish and reptiles. Select the option that applies only to embryos rather than adults (1 point)
Ogill slits that turn into gills
O hatch from and lay eggs
O scales as a form of skin
Ospines and tails
Answer:
Its option A
Explanation:
It cant be option B because the adults lay the eggs, option A is correct because they embryos gill slits turn into gills.
if the amounts of greenhouse gases such as carbon dioxide and methane continue to increase in the atmosphere, what will happen to the average temperature of Earth?
If greenhouse gases in the atmosphere continues to increase, then the
average temperature of Earth will increase too.
Greenhouse gases such as carbon dioxide and methane deplete the ozone
layer which shields the earth from radiations from the Sun. An increase in
these gases will therefore allow for more radiations to get to the earth.
This therefore brings about an increase in the average temperature of the
earth.
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Nitrogen monoxide is produced by combustion in an automobile engine. For the following reaction, 6.42 grams of nitrogen monoxide are mixed with excess oxygen gas . The reaction yields 8.53 grams of nitrogen dioxide . nitrogen monoxide ( g ) oxygen ( g ) nitrogen dioxide ( g ) What is the theoretical yield of nitrogen dioxide
Explanation:
[tex]6.42 \times \frac{1}{30} \times \frac{1}{1} \times \frac{46}{1} = 9.844[/tex]
[tex]8.53 \div 9.844 \times 100 = 86.65\%[/tex]
Determine the m/v% of a solution where 5 g of sugar is dissolved in enough water to yield 250 mL of total solution
Answer:
2 %m/v
Explanation:
Step 1: Given data
Mass of sugar (solute): 5 gVolume of solution: 250 mLStep 2: Calculate the %m/v of sugar in the solution
We will use the following expression.
%m/v = mass of sugar/volume of solution × 100%
%m/v = 5 g/250 mL × 100% = 2 %m/v
This means that there are 2 grams of sugar every 100 milliliters of solution.
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Calculate AEfor a system that absorbs 599,0 kJ of heat from its surroundings
and does 3510 kJ of work on its surroundings.
Answer:
-2911 kJ
Explanation:
Step 1: Given data
Heat absorbed by the system (Q): 599.0 kJ (By convention, when the systems absorbs heat, Q > 0)Work done by the system on the surroundings (W): -3510 kJ (By convention, when the systems does work on the surroundings, W < 0)Step 2: Calculate the change in the internal energy (ΔE)
We will use the following expression.
ΔE = Q + W
ΔE = 599.0 kJ + (-3510 kJ) = -2911 kJ
Without these we would not be able to bend our arms or legs. A. Levers B. Bones C.Joints
Answer:
Joints
Explanation:
Without joints we would not be able to bend our arms or legs. Hence option C is correct.
What is bending?Bending is defined as the behavior of a thin structural element under an external load that is applied perpendicular to the element's longitudinal axis. Plants and their parts are thought to bend as a result of a flexure process in which the curvature of the plant part changes. The plant organs' collenchyma gives them flexibility and elasticity, preventing them from breaking when bent.
The force required to bend, straighten, and support joints is applied by muscles to the bones. Muscles act in pairs of flexors and extensors because they may pull on bones but not put them back into place. The extensor muscle relaxes and stretches as the flexor muscle contracts to bend the joint.
Thus, without joints we would not be able to bend our arms or legs. Hence option C is correct.
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Please help me
5. Where is potential energy decreasing?
А B C D
Answer:
D
Explanation:
I believe it is D. your kinetic energy would be at b. A, the cart would be going at a constant rate, because there is no hill or steep slope.
Put the following experimental steps for the Acid-Base Equilibria (HCL and NaOH) in the correct order:
a. Perform a scout colorimetric titration. of diluted vinegar with NaOH.
b. One pair performs a careful colorimetric titration of diluted vinegar with NaOH and the other pair performs a potentiometic titration of diluted vinegar with NaOH.
c. Perform a scout colorimetric titration of HCl with NaOH.
d. One pair performs a careful colorimetric titration of HCl with NaOH and the other pair performs a potentiometic titration of HCl with NaOH.
e. Dilute a solution of commercial vinegar to prepare it for titration.
Answer:
e. Dilute a solution of commercial vinegar to prepare it for titration.
a. Perform a scout colorimetric titration of diluted vinegar with NaOH.
b. One pair performs a careful colorimetric titration of diluted vinegar with NaOH and the other pair performs a potentiometric titration of diluted vinegar with NaOH.
c. Perform a scout colorimetric titration of HCL with NaOH.
d. One pair performs a careful colorimetric titration of HCL with NaOH and the other pair performs a potentiometric titration of HCL with NaOH.
Explanation:
Titration is a process in which acid and base are introduced together to determine unknown concentration of acid or base. This is also known as neutralization reaction. The chemical process form salt and water as by products because acid molecules react with base molecules.
The experimental steps for the Acid-Base Equilibria in the correct order is e, a, b, c and d.
What is titration?Titration is a process in which we determine the concentration of any unknown acid and base by titrating them with the standard known concentration of base or acid.
In potentiometric titration, in the place of indicator potential difference is used across the analyte of electrolytic solution. And in colorimetric titration, absorbance of light is measured by the solution. Process of method which is involved in the titration is:
e. Dilute a solution of commercial vinegar to prepare it for titration.
a. Perform a scout colorimetric titration of diluted vinegar with NaOH.
b. One pair performs a careful colorimetric titration of diluted vinegar with NaOH and the other pair performs a potentiometric titration of diluted vinegar with NaOH.
c. Perform a scout colorimetric titration of HCL with NaOH.
d. One pair performs a careful colorimetric titration of HCL with NaOH and the other pair performs a potentiometric titration of HCL with NaOH.
Hence correct sequence is e, a, b, c and d.
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Advantages and disadvantages of using tidal energy instead of non-renewable energy sources.
Advantages of using tidal energy:
-Environment-friendly
-A highly predictable energy source
-High energy density
-Operational and maintenance costs are low
-An inexhaustible source of energy
Disadvantages of using tidal energy:
-High tidal power plant construction costs.
-Negative influence on marine life forms.
-Location limits.
-The variable intensity of sea waves.
Which affects both deep water and surface currents in the ocean? the wind the temperature of the water the Coriolis effect None of the above
Answer:
the wind and the temperature of water both drive ocean currents
Answer:
B. Write 'T' for true or 'F' for false statements :
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