Answer:
Glass blower
Explanation:
it's the best instrument
Alex drips hydrochloric acid onto a 5.9 g piece of magnesium in a single displacement reaction. How many molecules of HCl are required? 2HCl(aq) + Mg(s) → MgCl2(aq) + H2(g)
how do you do this?
2.96 × 10²³ molecules is required if Alex drips hydrochloric acid onto a 5.9 g piece of magnesium in a single displacement reaction
According to this question, hydrochloric acid (HCl) reacts with magnesium metal (Mg) to produce magnesium chloride and hydrogen has as follows:
2HCl(aq) + Mg(s) → MgCl2(aq) + H2(g)
Based on the balanced chemical equation above; 2 moles of HCl reacts with 1 mole of Mg. Next, we convert 5.9g of Mg to moles by using the formula; mole = mass/molar massWhere; Mg = 24g/mol
mole = 5.9/24
mole = 0.246mol of Mg
If 2 moles of HCl reacts with 1 mole of Mg. 0.246 mol of Mg will react with (0.246 × 2) = 0.492mol of HClTo convert mole to number of molecules, we multiply number of moles by 6.02 × 10²³ (Avogadro's no.)
Hence, number of molecules of HCl required is 0.492mol × 6.02 × 10²³
= 2.96 × 10²³ molecules of HClHCl
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How many moles of HNO3 are needed to prepare 5.7 liters of a 1.64 M solution of HNO3
We are given:
Volume of Solution: 5.7 Liters
Concentration: 1.64 Molar
Number of moles required:
We know that the formula for concentration (in molar) is:
M = N / V
where M is the concentration, N is the number of moles, and V is the volume of solution (in L)
plugging the given values in the equation:
1.64 = N / 5.7
N = 1.64 * 5.7
N = 9.35 moles
The surface of silver metal, Ag(s), became tarnished when it was exposed to oxygen, producing Ag2O. In Ag2O, the oxidation state of silver is 1. According to this information, silver metal was _____. Please choose the correct answer from the following choices, and then select the submit answer button. Answer choices reduced
Answer: The silver metal was OXIDIZED.
Explanation:
OXIDATION is defined as loss of electrons and increase in oxidation number of an atom.
Oxidation number is the charge on an ion in an ionic compound or the charge that an atom in a covalent compound would have it it were ionic. There are basic rules governing oxidation number, they include:
--> the oxidation number of elements in their free states is ZERO. Example O2, Cl2,Na, Al, Ag.
-->The oxidation number for an ion is the same as the size and sign of the charge on the ion. For example the oxidation number of Zn2+ is +2.
--> the sum of all the oxidation numbers of the elements in a compound is zero.
--> oxidation numbers are always written with either a positive or a negative sign.
On the other hand, reduction is the opposite of oxidation. As oxidation is taking place, reduction is also taking place. Reduction involves:
--> Gain of electron and
--> decrease in oxidation number
From the question, the silver metal had ZERO as it's oxidation number because it's in free state. After being exposed to oxygen to form silver oxide, the oxidation number became +1.
Since there is an increase in the oxidation number, the silver metal was OXIDIZED
Which method separates components of a mixture according to how quickly the particles travel through a medium?
A. distillation
B. evaporation
C. filtration
D. chromatography
Taking into account its definition, the correct answer is option D) Chromatography.
Chromatography is a method that allows the separation, identification and determination of chemical components in complex mixtures. By means of a chromatography it is possible to separate analytes that are very similar to each other in terms of their physico-chemical properties.
For the separation to occur, the principle of selective retention is used, which consists of the different behavior of the components of a mixture on a specific support (such as paper, a gas, a liquid) and a flowing liquid or gaseous phase. through the bracket.
In other words, there is a stationary phase immobilized on a support and a mobile phase that will drag the sample through the stationary phase. During this process, each component of the sample will move according to its own physicochemical characteristics. The general concept will be that those components that prefer the stationary phase are more retained, while those that prefer the mobile phase will move faster.
In summary, the components of the sample are distributed between two phases of different nature, as a consequence of the speed variation that is established when being dragged by a mobile, liquid or gaseous phase, through a stationary, solid or liquid phase.
Finally, the correct answer is option D) Chromatography.
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Determine the relative formula mass of dihydrogen monoxide using the periodic table below.
A. 18 g/mol
B. 17 g/mol
C. 16 g/mol
D. 2 g/mol
The relative atomic mass of dihydrogen monoxide is 18g/mol
Dihydrogen monoxide is a molecule containing two atoms of hydrogen and one atom of oxygen i.e. H2O. It is widely regarded as WATERTo calculate the relative atomic mass of dihydrogen monoxide (H2O), we make use of the atomic mass of each element.According to the periodic table:
Where; H = 1g/mol and O = 16g/mol
H2O = 1(2) + 16
= 2 + 16
= 18g/mol
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Which option is an isotope with 6 protons and 8 neutrons? (1 point)
O oxygen-6
o carbon-14
o oxygen-14
o carbon-8
Answer:
Carbon-14
Explanation:
It is because it have 6 protons and 8 neutrons which are added together to form an atomic mass of 14.
The mass number of an isotope is the sum of the number of protons and number of neutrons hence the correct answer is carbon-14.
Isotopes are atoms of the same element that has the same number of protons but different number of neutrons.
The atomic number is the same as the number of protons in the atom. Since there are six protons in the atom, the element must be carbon.
There are eight neutrons meaning that the mass number is 8 + 6 = 14
Therefore, the isotope is carbon-14.
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Preparation the buffer solution: initial pH of buffer solution: ____ Titration of a weak acid with a strong base: initial pH of weak acid: ____ final pH of weak acid: ____ Amount of NaOH added: ____ Titration Curve for Weak Acid with a Strong Base (Paste curve here.)
Answer:
pH of buffer solution is 7.0
Initial pH of Weak acid is 3.27
Final pH of weak acid is 3.07
Amount of NaOH added is 1ml
Explanation:
Titration is a process in which acid and base are introduced together until a neutral solution is achieved whose pH value is near to buffer solution which is 7.0, the pH value for acid is below 7 while pH value for base is above 7.
How are all compounds similar?
A. They are all made up of ions that are held together by attractions.
B. They are all made up of the same few elements.
C. They are all made up of atoms of two or more different elements.
D. They are all made up of atoms that share electrons.
Answer:
the answer is C
Explanation:
a molecule can be made up of two atoms of the same kind, as when two oxygen atoms bind together to make an oxygen molecule
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Problem 7 (Diffusion due to viscosity) If the viscosity of a solution is quadrupled, the rms-average distance of a collection of diffusing molecules from their starting point would be _________ over the same amount of time.
Answer:
1/2 the distance
Explanation:
If the viscosity of a solution is quadrupled then the distance of collection of diffusing molecules would be half over the same amount of time. The viscosity of the molecules is dependent on density of the liquid. It is independent to the volume of the liquid.
Which one of these statements is/are true: I. All redox reactions with positive emfs are spontaneous. II. If a redox reaction is spontaneous, it must be fast. III. A spontaneous redox reaction will have a cathode reaction that has a more negative reduction potential than the anode. III only. I and III are true. I only. II only. All of I, II, and III are true.
Answer:
yea all the answers are true
Redox reaction is the transfer of the electron from one species to another. All of the three statements are true about the redox reaction.
What is a redox reaction?A redox reaction is a type of chemical reaction in which the electrons are gained and lost by a species. The positive EMF of the cell results in spontaneous and will move the reaction in the forward direction.
In a redox reaction, the cathode reaction is comparatively more negative than the reduction potential present at the anode.
Therefore, option E. All I, II, and III are true.
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methyl ether, a useful organic solvent, is prepared in two steps. In the first step, carbon dioxide and hydrogen react to form methanol and water:(g) (g) (l) (l)In the second step, methanol reacts to form dimethyl ether and water:(l) (g) (l)Calculate the net change in enthalpy for the format
This question is incomplete, the complete question is;
Dimethyl ether, a useful organic solvent, is prepared in two steps.
In the first step, carbon dioxide and hydrogen react to form methanol and water:
CO₂(g) + 3H₂(g) → CH₃OH(l) + H₂O(l) ΔH₁ = -131.kJ
In the second step, methanol reacts to form dimethyl ether and water:
2CH₃OH(l) → CH₃OCH₃(g) + H₂O(l) ΔH₂ = 8.kJ
Calculate the net change in enthalpy for the formation of one mole of dimethyl ether from carbon dioxide and hydrogen from these reactions. Round your answer to the nearest kJ.
Answer:
the net change in enthalpy for the formation of one mole of dimethyl ether is -254 kJ
Explanation:
Given the data in the question;
For the First Step;
CO₂(g) + 3H₂(g) → CH₃OH(l) + H₂O(l) ΔH₁ = -131.kJ
For the First Step;
2CH₃OH(l) → CH₃OCH₃(g) + H₂O(l) ΔH₂ = 8.kJ
Using Hess's Law of Constant Heat Summation;
" regardless of the multiple stages or steps of a reaction, the total enthalpy change for the reaction is the sum of all changes "
we multiply step 1 reaction by the coefficient of 2
2CO₂(g) + 2×3H₂(g) → 2CH₃OH(l) + 2H₂O(l) ΔH₁ = 2 × -131.kJ
we have
2CO₂(g) + 6H₂(g) → 2CH₃OH(l) + 2H₂O(l) ΔH₁ = -262 kJ
2CH₃OH(l) → CH₃OCH₃(g) + H₂O(l) ΔH₂ = 8 kJ
{ 2CH₃OH cancels 2CH₃OH }
Hence, we have;
2CO₂ + 6H₂ → CH₃OCH₃(g) + 3H₂O(l)
So According to Hess's Law;
ΔH[tex]_{sum[/tex] = ΔH₁ + ΔH₂
we substitute
ΔH[tex]_{sum[/tex] = -262 kJ + 8 kJ
ΔH[tex]_{sum[/tex] = -254 kJ
Therefore, the net change in enthalpy for the formation of one mole of dimethyl ether is -254 kJ
Draw the structure of the organic product(s) of the Grignard reaction between methyl benzoate and excess phenylmagnesium bromide, followed by aqueous workup. You do not have to consider stereochemistry. If a compound is formed more than once, add another sketcher and draw it again. Alternatively, you may use the square brackets tool to add stoichiometries greater than one. Draw one structure per sketcher. Add additional sketchers using the drop-down menu in the bottom right corner. Separate multiple products using the sign from the drop-down menu.
Answer:
See explanation and image attached
Explanation:
The product of the Grignard reaction between methyl benzoate and excess phenylmagnesium bromide is triphenyl methanol.
The reaction proceeds by nucleophillic reaction as the carbonyl moiety is attacked. A tetrahedral intermediate is formed. Loss of the -OMe group is accompanied by the attack of the first molecule of PhMgBr.
Attack by a second PhMgBr molecule yields trimethyl phenoxide. Protonation of this specie yields the final product which is obtained by aqueous workup.
Which of the given statements best represent what to do in the event of a spill of concentrated sulfuric acid.
A. First, rinse the affected area with copious amount of water.
B. First, rinse the affected area with copious amounts of sodium hydroxide.
C. Second, treat the area with aqueous sodium bicarbonate solution.
D. Second, add sand to absorb the remaining acid.
Hello, I am a bit stuck on this. Could someone help?
Write the balanced equation for the hydration of CuSO4CuSO4. Indicate the physical states using the abbreviations (ss), (ll), or (gg) for solid, liquid, or gas, respectively. Use (aqaq) to indicate the aqueous phase. Indicate appropriate charges on negative and positive ions if they are formed.
Answer:
CuSO4(s) + 5H2O(l) ----> CuSO4.5H2O(s)
Explanation:
Hydration is the process by which anhydrous CuSO4 acquires molecules of water of crystalization to form the pentahydrate.
The water of crystalization becomes attached go the crystals of the CuSO4 to form the hydrated salt.
Beginning with solid anhydrous CuSO4 we have;
CuSO4(s) + 5H2O(l) ----> CuSO4.5H2O(s)
A person uses 400.8 kcal of energy to run a race. Convert the energy used for the race to the following energy units:
(provide an answer in 4 significant figures)
Calories
calories
Food Calories
Joules
Kilojoules
Hint: 1kcal=4.184kJ
Calories, we know that fat burn is calories.
A 25.00 gram sample of an unknown metal initially at 99.0 degrees Celcius is added to 50.00 grams of water initially at 10.55 degrees Celcius. The final temperature of the system is 20.15 degrees Celcius. Calculate the specific heat of the metal. (The specific heat of water is 4.184 J/g*C).
Answer:
1.0188 J/g*C
Explanation:
Using the formula; Q = m × c × ∆T
Q(water) = -Q(metal)
m × c × ∆T (water) = -{m × c × ∆T (metal)}
According to this question,
mass of metal = 25g
initial temp of metal = 99°C
mass of water = 50g
initial temp of water = 10.55°C
final temperature of the system = 20.15°C
c of water = 4.184 J/g*C
50 × 4.184 × (20.15 - 10.55) = 25 × c × (20.15 - 99)
209.2 × 9.6 = 25c × -78.85
2008.32 = -1971.25c
c = 2008.32 ÷ 1971.25
c of metal = 1.0188 J/g*C
The element Co exists in two oxidation states, Co(II) and Co(III), and the ions form many complexes. The rate at which one of the complexes of Co(III) was reduced by Fe(II) in water was measured. Determine the activation energy of the reaction from the following data:
T(K) K(s^-1)
293 0.054
298 0.100
We measured the Fe(II) reduction of one of the Co(III) complexes by water at a rate of about 0.545 kJ/mol (to three significant figures).
How is activation energy determined?Calculating a Reaction's Activation Energy A reaction's rate is influenced by the temperature at which it is carried out. The molecules travel more quickly and clash more frequently as the temperature rises. Moreover, the molecules contain greater kinetic energy.
We can use the Arrhenius equation to calculate the reaction's activation energy:
k = A × exp(-Ea/RT)
When the activation energy Ea, the rate constant k, the gas constant R, and the temperature T in Kelvin are all present.
Finding the natural logarithm of the equation's two sides results in:
ln(k) = ln(A) - (Ea/RT)
This equation can be rearranged to take a linear form:
ln(k) = (-Ea/R) × (1/T) + ln(A)
y = mx + b, where (1/T) is x, (-Ea/R) is the slope, and ln(A) is the y-intercept, has the form of a linear equation.
We can get the slope of the line using the given data:
slope = (-Ea/R) = (ln(k2/k1)) / (1/T2 - 1/T1)
where the rate constants for temperatures T1 and T2, respectively, are k1 and k2.
substituting the specified values:
k1 = 0.054s⁻¹ at 293 K
k2 = 0.100s⁻¹ at 298 K
T1 = 293 K
T2 = 298 K
slope = (-Ea/R)
= (ln(0.100/0.054)) / (1/298 - 1/293)
= 65.5 kJ/mol
Therefore, the activation energy of the reaction is:
Ea = slope * R = 65.5 kJ/mol × 8.314 J/mol-K = 545 J/mol
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How to distinguish between ethanol and 2 -methyl-2-propanol
Answer:
There are many reagents.
1. Use acidified potassium permanganate solution
2. Use acidified potassium dichromate solution
3. Fehling solution.
4. Silver/ oxygen at 500°C
5. Copper/ oxygen at 300°C
6. Lucas reagent ( anhydrous zinc and conc. hydrochloric acid)
Explanation:
Observations:
[with acidified potassium permanganate solution]
» Ethanol : The purple solution turns colourless.
» 2-methyl-2-propanol : no observable change.
[with acidified potassium dichromate solution]
» Ethanol : orange solution turns green
» 2-methyl-2-propanol : no observable change.
[Fehling solution]
» Ethanol : a white precipitate is formed
» 2-methyl-2-propanol : no observable change
Give the change in condition to go from a gas to a solid. Group of answer choices cool or increase pressure cool or reduce pressure increase heat or reduce pressure increase heat or increase pressure none of the above
Answer:
cool or increase pressure
Explanation:
For a gas to form solid. There must be reduced heat and pressure. The deposition of gas into solid occurs through the removal of thermal energy. The air looses thermal energy and changes into solid.What does the third quantum number (m) describe?
A. Which energy level the electron is in
B. What type of orbital the electron is in
C. What direction the electron is spinning
D. The specific orbital within a sublevel
The third quantum number (m) describes the specific orbital within a sublevel. The correct answer is option D.
Quantum numbers are a set of four numbers that describe the properties of an electron in an atom. They specify the energy, position, and orientation of an electron in an atom.
The third quantum number (m) is also called the magnetic quantum number. It describes the orientation of the orbital in space. Each orbital within a sublevel has a different orientation in space, and the magnetic quantum number tells us which orbital we are talking about.
The value of m can range from -l to +l, where l is the second quantum number (the angular momentum quantum number). The value of l determines the number of orbitals in a sublevel, and the value of m determines the specific orbital within that sublevel.
In conclusion, the third quantum number (m) describes the specific orbital within a sublevel. It tells us how the orbital is oriented in space, and it can have values ranging from[tex]\rm -l \ to +l[/tex], where l is the second quantum number.
Option D is the correct answer.
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Which of the following pairs lists phase changes that both give off energy?
a) Freezing and condensation
b) Deposition and vaporization
c) Vaporization and melting
d) Condensation and sublimation
Answer:
a) Freezing and condensation
Explanation:
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A nitrogen ion has a mass of 14 and a charge of +2. Which subatomic particles does it contain? (1 point)
O 2 protons, 6 neutrons, and 6 electrons
O 7 protons, 7 neutrons, and 5 electrons
O 4 protons, 4 neutrons, and 6 electrons
o 7 protons, 7 neutrons, and 9 electrons
Answer:
7 protons, 7 neutrons, and 5 electrons
Explanation:
the formula for atomic weight=no.of protons + no. of electrons this shortens the options into b or d and second part says that the ion has charge +2 which means it has lost two electrons. so no. of electrons=no.of electrons in nitrogen atom - 2=5.
Nitrogen ion with a charge of +2 has 7 protons, 7 neutrons, and 5 electrons
Explanation:
To obtain the right answer to the question, we must determine the number of proton, neutron and electron of nitrogen ion. This can be obtained as illustrated follow.
Step 1:Data obtained from the question.
Mass number = 14
Charge = +2
Step 2:Determination of the number of proton.
The atomic number of an element is simply the number of protons in the atom of the element.
Atomic number of nitrogen = 7
Thus, the proton number of nitrogen is 7.
NOTE: The atomic number of an element does not change be it atom or ion, it remains the same.
Therefore the proton number of nitrogen ion is 7
Step 3:Determination of the number of neutron
Mass number = 14
Proton number = 7
Neutron number =?Mass number = Proton + Neutron
14 = 7 + Neutron
Collect like terms
14 – 7 = Neutron
Neutron = 7Step 4Determination of the number of electrons.
Charge = +2
Proton number = 7
Electron number =?Charge = Proton – Electron
+2 = 7 – Electron
Collect like terms
2 – 7 = – Electron
–5 = – Electron
Multiply through by –1
Electron = 5SUMMARY:Nitrogen ion with a charge of +2 has:
1. 7 protons
2. 7 neutrons
3. 5 electrons.
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All of the following are TRUE for activities and activity coefficients, except: A) activity for a chemical species is the product of concentration and activity coefficient. B) the activity coefficient corrects for non-ideal behavior due to ionic strength. C) as ionic strength increases, the value of the activity coefficient increases. D) for ions, the activity coefficient approaches unity as the ionic strength approaches 0. E) the activity coefficient for neutral molecules is approximately unity.
Answer:
C) as ionic strength increases, the value of the activity coefficient increases.
Explanation:
The effective concentration of ions available for reactions is known as the activity of the ion.
The activity coefficient important in chemistry because it accounts for the deviation of a solution from ideal behaviour.
The activity of a chemical species is defines as the product of concentration and activity coefficient.
Following the Debye–Hückel limiting law; log γ = −0.509z2I1/2. The ionic strength of a solution tends to increase as the activity coefficient (γ) of the ion decreases.
I performed an experiment and mixed copper nitrate and potassium iodide. When they reacted, they formed a precipitate, even though solubility rules would not lead one to predict so because potassium nitrate is obviously soluble and so should copper (II) iodide. One can deduce from the formation of a precipitate that copper is reduced. Write a proposed reaction for the oxidation reduction of copper (II) iodide. Justify the choice of the substance that reduces the copper based on experimental evidence. Also, justify the choice using the atomic structure of potassium ion and iodide ion.
Answer:
2Cu2^+ + 2I^- ----> 2Cu^+ + I2
Explanation:
The reaction performed in the experiment is;
2 Cu(NO3)2 + 4 KI → 2 CuI (s) + 4 KNO3 + I2
The iodide ions reduces Cu^2+ to Cu^+ which is insoluble in water hence the precipitate. This is so because iodine is a good oxidizing agent seeing that it requires one electron to fill its outermost shell. Potassium on the other hand is a good reducing agent since it easily looses its one electron.
The oxidation - reduction equation is as follows;
2Cu2^+ + 2e ----> 2Cu^+ reduction half equation
2I^- ----> I2 + 2e. Oxidation half equation
Balanced redox reaction equation;
2Cu2^+ + 2I^- ----> 2Cu^+ + I2
313.9 liters of a gas has a pressure of 390.89 kPa at 76.6°C. If the pressure increases to 718.3 kPa and the temperature to 154.2°C, what would be the new volume of the gas?
A.) 210
B.) 353
C.) 470
D.) 209.92
Explanation:
P1V1/T1 = P2V2/T2
=((390.89×313.9)/76.6)×((718.3×V2)/154.2)
= (122700.371/76.7) × ((718.3×V2)/154.2)
make V2 the subject of the formula...
V2 =(122700.371×154.2)/(76.6×718.3)
V2 =18920397.21/55021.78
V2 = 343.87
describe cold blooded animal.also some five example.
Answer:
Cold blooded animals are animals which stay in water
Explanation:
Examples are;snakes,tortoises,turtles,crocodiles,alligators
The standard redox potentials of isolated components of an electron transport chain in a cyanobacterium are found to be as follows:
Complex A: standard redox potential: -100 mV
Complex B: standard redox potential: -780 mV
Complex C: standard redox potential: +510 mV
Complex D: standard redox potential: +310 mV
Plastocyanin: standard redox potential: +360 mV
Which complex will likely have a binding site with high affinity for reduced plastocyanin?
A. Complex A.
B. Complex B.
C. Complex C.
D. Complex D.
Answer:
B. Complex B.
Explanation:
Complex B will have binding site with high affinity for reduced plastocyanin due to greater redox potential. The high number of redox potential will will transport electron chain in cyanobacteria.
Redox potential is the measure of the electron gain or loss to the electrode. For reduced plastocyanin complex B will have the highest affinity.
What is electron affinity?Electron affinity is the energy released when the atom gets attached to the atom or other molecule. The high number of redox potential increases the electron transport in the cell.
The greater the redox potential more will be its tendency to show electron affinity. To bond with reduced species, the oxidized species must have greater redox potential.
Therefore, option B. complex b will have the highest affinity.
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Which of the following is an example of an optional deduction ? " a ) Medicare Ob ) Social Security c ) Retirement plan d ) State tax
Medicare
United states program for people who are older than 60
The critical mass of fissionable material is the largest mass necessary to sustain a nuclear fission chain reaction. single mass value that can sustain a nuclear fission chain reaction. mass at the critical point, which can sustain a nuclear fission chain reaction. smallest mass necessary to sustain a nuclear fission chain reaction.
Answer:
smallest mass necessary to
Explanation:
The critical mass for a fissionable material is the smallest and the lowest quantity of a particular fissile material required to generate a self-sustaining fission chain reaction under specified conditions. The size's features are determined by a number of variables. Examples include;
The type of fissile material employed, its purity as well as concentration, the shape of the surrounding reaction system e.t.c.
Answer:
Fill in the blanks with the terms that complete the sentences about nuclear power plants.
Without a critical mass of fissionable material, a nuclear reaction cannot be sustained. The turbine is powered by steam.
Explanation:
The answers to both parts are marked in bold. I just answered these questions on Edge and they were both correct. Hope this helps. Please mark my answers as the brainiest. THANK YOU!!!!!!!!!!!!!!!!!!!
