Answers
Answer:
45, 34, 36
Explanation:
The atomic number of Selenium is 34 and the atomic number is 79 also the atom has gained two electron denoted by superscript -2
number of neutrons = mass number - atomic number = 79 - 34 = 45
number of proton = atomic number = 34
number of electron = 34 + 2 = 36. In an atom the number of proton is always equal to number of electron if the atom is neutral but this Se atom has gain two so the number of electron will exceed the number of proton by 2.
The Se ion has 34 protons, 45 neutrons and 36 electrons.
The mass number (A) is given by the sum of the protons and neutrons:
A = protons + neutrons = 79
From the Periodic Table, we can see that the chemical element Selenium (Se) has an atomic number (Z) of 34, which is equal to the number of protons of a chemical element:
Z = protons = 34
Thus, we calculate the number of neutrons as the difference between A and Z:
neutrons = A - Z = 79 - 34 = 45
In a neutral atom (without electric charge), the number of electrons is equal to the number of protons. Since Se ion has 34 protons and a charge of -2, it has 34 electrons to be neutral and then it gained 2 electrons, so the number of electrons is equal to:
electrons = protons + 2 = 34 + 2 = 36
You can learn more about mass number, atomic number and subatomic particles here:
Related Questions
Exactly 1.5 g of a fuel burns under conditions of constant pressure and then again under conditions of constant volume. In measurement A the reaction produces 25.9 kJ of heat , and in measurement B the reaction produces 23.3 kJ of heat. Which measurement (A or B) corresponds to conditions of constant pressure? Which one corresponds to conditions of constant volume? Explain.
What is the principal reason we must consider the uncertainty principle when discussing electrons and other subatomic particles but not when discussing our macroscopic world?
Calculate the mass of a sample of lead (cPb = 0.16 J/g℃) when it loses 200 J cooling from 75.0℃ to 42.0℃.
A sample of iron having a mass of 93.3g is heated to 65.58OC is placed in 75.0g ofwater raising the temperature from 16.95 OC to 22.24 OC. Find the specific heatcapacity for this iron sample. The answer you find has had some lab errors due tohuman mistakes. Find your percent error for your work using %Error = [(Expected - Actual) / (Expected Yield)] x100
Answers
Answer: correct option is the option B= 2.6 × 10^-5 mol.sec^-1
Explanation:
Check attached file/picture for the plot of graph of reaction velocity against substrate concentration.
Initial velocity can be defined as the velocity at the beginning of an enzyme-catalyzed reaction. It is usually denoted as V°.
In the equation of reaction below;
A + B----------> [AB] ------------>Product
<--------
Where the forward reaction is k1 that is the rection producing the intermediate [AB].
And, the backward reaction is k-1 that is the arrow pointing back to the Reactants.
K2 is the arrow from the intermediate [AB] to the products.
Note that k1 and k-1
represent rapid non-covalent dissociation of substrate from enzyme active site. Also, K2 is the rate constant for the formation of the products.
In order to calculate the initial velocity,V° we need to use the Michaelis- Menteen equation.
V° = Vmax ×(S)/ Km + (S)-------------------------------------------------------------(1).
From the question the parameters given are;
Vmax = 6.5 x 10–5 mol•sec–1 , [S] = 3.0 x 10–3 M, and KM = 4.5 x 10–3 M.
Therefore, slotting in the above parameters into the equation (1) above, we have;
V° = 6.5 x 10–5 mol•sec–1 × 3.0 x 10–3 M / 4.5 x 10–3 M + 3.0 x 10–3 M.
Initial velocity,V° = 2.6 x 10-5 moles per sec..
Answers
Answer:
3 > 2> 1
Explanation:
Aromatic compounds undergo electrophilic substitution reaction which passes through a positively charged intermediate to yield the product.
Substituted benzenes may be more or less reactive towards electrophilic aromatic substitution than benzene molecule depending on the nature of the substituent.
Certain substituents increase the ease of reaction of benzene towards aromatic substitution.
If we look at the compounds closely, we will notice that toluene reacts readily with CH3Cl / AlCl3. This is because, the methyl group is electron donating hence it stabilizes the positively charged intermediate produced in the reaction.
Carbonyl compounds are electron withdrawing substituents hence they decrease the magnitude of the positive charge and hence decrease the rate of electrophilic aromatic substitution.
B. only 2
C. 1
D. Either 2 or 3
Answers
Second step of the mechanism is slow step.
B. Only 2
Rate of reaction:
It is the speed at which a chemical reaction takes place, defined as proportional to the increase in the concentration of a product per unit time and to the decrease in the concentration of a reactant per unit time.
Chemical reaction:
The reaction mechanism is as follows.
Second step is the slowest step, thus the rate determining step.
Therefore, rate of reaction can be represented as:
Thus, option B is correct.
Find more information about Rate of reaction here:
Answer:
Second step of the mechanism is slow step.
Explanation:
The given chemical reaction is as follows
The mechanism of the reaction is as follows.
The rate of the reaction.
Therefore, Step -2 must be slow.
Answers
The theoretical yield : = 10.251 g
Further explanation
Given
Reaction
3H₂(g)+N₂(g)→2NH₃(g)
1.81 g H₂
10.2 g N₂
2.19 g NH₃
Required
The theoretical yield
Solution
Find limiting reactant :
H₂ : 1.81 g : 2 g/mol = 0.905 mol
N₂ : 10.2 g : 28 g/mol = 0.364 mol
mol : coefficient
H₂ = 0.905 : 3 = 0.302
N₂ = 0.364 : 1 = 0.364
H₂ as a limiting reactant(smaller ratio)
Moles NH₃ based on H₂, so mol NH₃ :
= 2/3 x mol H₂
= 2/3 x 0.905
=0.603
Mass NH₃ :
= mol x MW
=0.603 x 17 g/mol
= 10.251 g
1. _____. the phase change of a substance from the solid state directly to the gaseous state; for example, dry ice, moth balls, or solid air freshener
2. _____. a form of energy transferred (by way of conduction, convection, or radiation) by virtue of a difference in temperature; heat is energy in transit; heat is energy flow, measured in energy units
3. _____. matter with definite volume and definite shape
4. _____. theory in physics based on the fact that particles of matter are in vigorous motion and that the temperature of a substance increases with an increase in either the average kinetic energy of the particles or the average potential energy of separation of the particles, or in both, when heat is added
5. _____. a measure of how hot or cold something is; a measure of the average kinetic energy of the particles of a substance
6. _____. matter with no definite volume or shape
7. _____. the process by which a gas changes phase directly to a solid; for example, the formation of frost
8. _____. a gaslike state of matter consisting of positively charged ions, free electrons, and neutral particles; found in stars, the sun, solar wind, lightning, and fire; unlike gases, plasmas are good conductors of electrical currents
9. _____. net absorption of energy
10. _____. the transfer of heat through matter by way of the collision of molecules
11. _____. heat; energy transferred due to temperature differential that becomes associated with potential energy and kinetic energy on a molecular level
12. _____. the process by which water vapor changes from gas to liquid
13. _____. in a closed system in changing from one form to another, matter and energy cannot be created or destroyed; in this sense, conservation means that the physical quantity of matter and energy is entirely preserved during transformations and reactions
14. _____. physical form of matter, such as solid, liquid, and gas; a distinct state of matter in a system; matter that is identical in chemical composition and physical state, and is separated from other material by the phase boundary; for example, the reaction occurs in the liquid phase of the system
15. _____. the process by which water changes to water vapor
16. _____. net release of energy
17. _____. SI-derived unit to measure energy, work, and quantity of heat; for work, a joule is the amount of work done by a force of 1 N acting through 1 m; also newton-meter
18. _____. matter with definite volume but no definite shape.
WORDS.
1.
condensation
2.
conduction
3.
conservation
4.
depostion
5.
endothermic
6.
evaporation
7.
exothermic
8.
gas
9.
heat
10.
joule
11.
kinetic theory
12.
liquid
13.
phase
14.
plasma
15.
solid
16.
sublimation
17.
temperature
18.
thermal energy
Answers
- Sublimation;
- Heat*;
- Solid;
- Kinetic Theory;
- Temperature;
- Gas;
- Deposition;
- Plasma;
- Endothermic;
- Conduction;
- Thermal Energy*;
- Condensation;
- Conservation;
- Phase;
- Evaporation*;
- Exothermic;
- Joule;
- Liquid.
Consider looking up those definitions in a dictionary or in the appendix of your textbook.
Answer is in the Word document.
Answers
Answer:
the difference is they arnt close
Explanation:
Answer:
China is communist, Europe isn't.
Explanation: