How abundant is Polonium in the earth's crust?
Even in pitchblende, polonium is exceedingly rare: 1,000 tons of ore must be treated to yield 40 milligrams of polonium. It has a one-part-in-ten-thousandth-thousandth-thousandth-thousandth-thousandth-thousandth It is found in nature as a byproduct of the radioactive decay of uranium, thorium, and actinium.
Atomic Number: 210
Many fundamental concepts are at the heart of chemistry. Match the description to the name.
Answer:
you dony have a picture for me to match them
Explanation:
what are the solar home lighting
Answer:
Sunlight
Explanation:
Home lighting System is powered by solar energy using solar cells that convert solar energy (sunlight) directly to electricity. The electricity is stored in batteries and used for the purpose of lighting whenever required
For an imaginary closed economy, T = $5,000; S = $11,000; C = $48,000; and the government is running a budget surplus of $1,000. Then
Based on the information given, the private savings will be $10000 and the gross domestic product is $63000.
From the information given, he following can be gotten:
T = $5,000S = $11,000C = $48,000Budget surplus = $1000Since, S = Y - C - G
11000 = Y - 48000 - G
Y - G = 48000 + 11000
Y - G = 59000
Budget surplus = T - G = 1000
5000 - G = 1000
G = 5000 - 1000 = 4000
The GDP will be:
Y - G = 59000
Y - 4000 = 59000
Y = 59000 + 4000 = 63000
Private savings = Y - T - C
Private savings = 63000 - 5000 - 48000
Private savings = 10000
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the size of camphor kept in store house gradually decrease in size after few а days?
Answer:
Because it goes through the process of sublimation.
Explanation:
Apply Concepts
6. Describe the ecosystem in the picture.
What is the mass of an aluminum block if the density of aluminum is 2.70
g/cm and the volume of that block is 4.8 cm?
Answer: 50 M
Explanation:
Mass
Density×Volume2.7(4.8)11.6111.6gFormula used
Density=Mass/VolumeWhich of the following is a challenge of prosthetic engineering that has been met through tissue engineering?
- Predicting failure
- Biocompatibility
- Strength
- Power
Answer:
Biocompatibility
Explanation:
I’m a genius and it’s the answer :D
Biocompatibility is a challenge of prosthetic engineering that has been met through tissue engineering. Hence, option B is correct.
What is Biocompatibility?Biocompatible materials are used in medical devices, such as menstrual cups, stents, or ventilators.
A biocompatibility problem might happen when some of the materials are trapped in the patient's gingival sulcus.
Tissue engineering is an important field of regenerative medicine for tissue repair (after damaged caused by a disease or an accident, for example).
To offer this possibility, stem cells are important tools owing to their capacity to differentiate into a large number of cells according to the stimuli provided.
Hence, option B is correct.
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A 0.500-g sample containing Na2CO3 plus inert matter is analyzed by adding 50.0 mL of 0.100 M HCl, a slight excess, boiling to remove CO2, and then back-titrating the excess acid with 0.100 M NaOH. If 5.6 mL NaOH is required for the back-titration, what is the percent Na2CO3 in the sample?
The percentage by mass of Na2CO3 in the sample is 48%.
The equation of the reaction of Na2CO3 with HCl;
Na2CO3(aq) + 2HCl(aq) ------> 2NaCl(aq) + H2O(l) + CO2(g)
Since the HCl is in excess, the excess is back titrated with NaOH as follows;
NaOH (aq) + HCl(aq) ---->NaCl(aq) + H2O(l)
Number of moles of HCl added = 0.100 M × 50/1000 L = 0.005 moles
Number of moles of NaOH added = 5.6/1000 × 0.100 M = 0.00056 moles
Since the reaction of NaOH and NaOH is 1:1, 0.00056 moles of HCl reacted with excess HCl.
Amount of HCl that reacted with Na2CO3 = 0.005 moles - 0.00056 moles = 0.0044 moles
Now;
1 mole of Na2CO3 reacts with 2 moles of HCl
x moles of Na2CO3 reacts with 0.0044 moles of HCl
x = 1 mole × 0.0044 moles / 2 moles
x = 0.0022 moles
Mass of Na2CO3 reacted = 0.0022 moles × 106 g/mol = 0.24 g
Percentage of Na2CO3 in the sample = 0.24 g/ 0.500-g × 100/1 = 48%
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Which law states that energy cannot be created or destroyed, but can change from one form to another?
- the law of conservation of energy
- the law of conservation of matter
- the law of gravity
- the law of motion
answer - (the law of conservation of energy)
Answer:
the law of conservation of energy
The decomposition of ethanol (C2H5OH) on an alumina (Al2O3) surface C2H5OH1 g2 h C2H4 1 g2 1 H2O1 g2 was studied at 600 K. Concentration versus time data were col- lected for this reaction, and a plot of [A] versus time resulted in a straight line with a slope of 24.00 3 1025 mol/L s. a. Determine the rate law, the integrated rate law, and the value of the rate constant for this reaction. b. If the initial concentration of C2H5OH was 1.25 3 1022 M, calculate the half-life for this reaction. c. How much time is required for all the 1.25 3 1022 M C2H5OH to decompose?
The rate constant for the decomposition of ethanol on an alumina surface is 24.00 × 10²⁵ M.
The rate law is: rate = 24.00 × 10²⁵ M/s
The integrated rate law is: [C₂H₅OH]t = [C₂H₅OH]₀ - 24.00 × 10²⁵ M/s × t
If the initial concentration of C₂H₅OH was 1.25 × 10²² M, the half-life is 2.60 × 10⁻⁵ s.
The time required for all the 1.25 × 10²² M C₂H₅OH to decompose is 5.21 × 10⁻⁵ s.
Let's consider the decomposition of ethanol on an alumina surface.
C₂H₅OH(g) ⇒ C₂H₄(g) + H₂O(g)
The plot of [A] vs time (t) resulted in a straight line, which indicates that the reaction follows zero-order kinetics.
The slope, 24.00 × 10²⁵ M/s, represents the rate constant, k.
What is zero-order kinetics?It is a chemical reaction in which the rate of reaction is constant and independent of the concentration of the reacting substances
The rate law for zero-order kinetics is:
rate = 24.00 × 10²⁵ M/s
The integrated rate law for zero-order kinetics is:
[C₂H₅OH]t = [C₂H₅OH]₀ - 24.00 × 10²⁵ M/s × t
What is the half-life?Is the time for the amount of substance to decrease by half.
If the initial concentration of C₂H₅OH was 1.25 × 10²² M, we can calculate the half-life [t(1/2)] using the following formula.
t(1/2) = [C₂H₅OH]₀ / 2 × k
t(1/2) = (1.25 × 10²² M) / 2 × (24.00 × 10²⁵ M/s) = 2.60 × 10⁻⁵ s
We can calculate the time required for all the 1.25 × 10²² M C₂H₅OH to decompose using the integrated rate law.
[C₂H₅OH]t = [C₂H₅OH]₀ - 24.00 × 10²⁵ M/s × t
0 M = 1.25 × 10²² M - 24.00 × 10²⁵ M/s × t
t = 5.21 × 10⁻⁵ s
The rate constant for the decomposition of ethanol on an alumina surface is 24.00 × 10²⁵ M.
The rate law is: rate = 24.00 × 10²⁵ M/s
The integrated rate law is: [C₂H₅OH]t = [C₂H₅OH]₀ - 24.00 × 10²⁵ M/s × t
If the initial concentration of C₂H₅OH was 1.25 × 10²² M, the half-life is 2.60 × 10⁻⁵ s.
The time required for all the 1.25 × 10²² M C₂H₅OH to decompose is 5.21 × 10⁻⁵ s.
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A Carnot engine takes 2000 j of heat from a reservoir at 500 k, does some work and discards some heat to a reservoir at 350k . how much work does it do, how much heat is discarded, and what is it's efficiency?
Answer:
Explanation:
The Carnot engine is a theoretical or conceptual heat engine that has a higher efficiency than any practical or theoretical heat engine working between the same temperature range. The theoretical efficiency of a Carnot engine is considered as the highest efficiency and no practical heat engines can operate at that efficiency. A Carnot engine draws heat energy, performs useful work and the leftover energy is released from the working substance. According to the second law of thermodynamics, there must be a temperature gradient between the heat energy drawing point and release point of the heat engine.
which planet is closests to the moon
Answer:
Earth
Explanation:
Answer:
Earth
Explanation:
Hope this helps! Pls give brainliest! Also, please sub to Kgirl633 on yt.
If the concentration of KMnO4 was 0.0235 M, calculate the number of moles of MnO4- ions that completely reacted with the H2C2O4
The number of moles of KMnO4 is 0.0006 moles.
The equation of the reaction is;
6 H^+(аq) + 2 МnO4^- (аq) + 5 Н2С2O4(аq) → 10 CO2 (g) + 8 H20 (l) + 2 Mn²+ (aq)
We can see that the volume of the titrant used = Final - initial burette reading
= 29.6 mL - 3.4 mL = 26.2 mL
Number of moles of H2C2O4 = 0.139 g/90 g/mol = 0.0015 moles
If 2 moles of MnO4- reacts with 5 moles of H2C2O4
x moles of MnO4- reacts with 0.0015 moles of H2C2O4
x = 2 moles × 0.0015 moles / 5 moles
x = 0.0006 moles
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Which of the following best represents a chemical change?
A. Chopping wood
B. Silver tarnishing (changing color)
C. Grape kool-aid mix dissolving in water
D. Dry ice turning into a gas (sublimation- a change of state)
B. silver tarnishing
Which of the following ideas did Greek philosopher Democritus contribute to the atomic theory?
A. Matter is composed of only one kind of particle, which can be easily destroyed.
B. Every element has a specific type of atom, which remains the same size in all forms of matter.
C. All matter is composed of small particles, which combine to make larger objects.
D. Each object is made up of one atom, which varies in size from very small to very large.
I will mark the correct answer the brainliest
Answer:
c. all matter is composed of small particles,which combine to make larger objects
one of the biggest dangers of storms that produce heavy rains or storm surges is ___.
A. Low Temperatures
B. Flooding
Answer:
B. Flooding
Explanation:
Flooding can be caused by heavy rains/storm surges. Hope this helped!
_________.__________ and___________ are energy science
Answer:
Chemical, Mechanical, and Nuclear Energy
Explanation:
Sodium chloride reacts with copper sulfate to produce sodium sulfate and copper chloride.
2NaCl(aq) + CuSO4(aq) → Na2SO4(aq) + CuCl2(s)
+
This equation represents a
O synthesis reaction.
O decomposition reaction.
O single replacement reaction.
O double replacement reaction.
O
Sodium chloride reacts with copper sulfate to produce sodium sulfate and copper chloride.
2NaCl(aq) + CuSO4(aq) → Na2SO4(aq) + CuCl2(s)
+
This equation represents a
O synthesis reaction.
O decomposition reaction.
O single replacement reaction.
O double replacement reaction.
Answer :double replacement reaction
ありがとう！
Sodium chloride reacts with copper sulfate to produce sodium sulfate and copper chloride. This equation represents a double replacement reaction. Therefore, the correct option is option D.
What is double replacement reaction?In a double replacement process, the ions in two input ionic compounds are exchanged for the same ions in two new product compounds. When two reactants swap cations or anions to produce two new products, the process is known as a double replacement reaction.
Double displacement reactions and metathesis reactions are other names for double replacement processes. Double replacement reactions include neutralisation, precipitation, and gas production. Sodium chloride reacts with copper sulfate to produce sodium sulfate and copper chloride. This equation represents a double replacement reaction.
Therefore, the correct option is option D.
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Where do you put the value for how many of each atom you need?
Multiple choice
A. Below and before the symbol.
B. Above and after the symbol.
C. Below and after the symbol.
D. Above and before the symbol.
Answer:A
Explanation
:
Which is warmer -30C or -30 F?
-30°F is warmer than -30°C.
The -ve sign is used when the temperature drops down. Celsius is the greater unit. By converting, -30°F = -1.11°C (approx.) We know that, -1.11 > -30. So, -30°F (-1.11°C) is warmer than -30°C.
Formula :-
(x°C × 9/5) + 32 = y°F
_____
Hope it helps ⚜
Answer:
-30 c is warmer
Explanation:
-30 c =-22 f
-30 f=-34.444 c
NEED HELP ASAP WILL GIVE BRAINLIEST
Answer:
2.83
Explanation:
Molar concentration (mol/litre) = mass/molar mass × 1000/volume(in ml)
0.849 = mass/60.09 × 1000/55.5
mass = (0.849 × 60.09 × 55.5)/1000
= 2.8314
To 2 decimal places = 2.83
Why does the Hubble Space Telescope take clearer pictures than other telescopes?
Answer:
Space-based telescopes like Hubble get a much clearer view of the universe than most of their ground-based counterparts. ... Ground-based telescopes can't do the same, because the Earth's atmosphere absorbs a lot of the infrared and ultraviolet light that passes through it.
What do these white-precipitate reactions have in common? (choose the best
answer)
They all have a chromate (Cro, 2) ion.
They all have a chloride ( Cl-1) ion.
They all made the same color.
They all have a barium (Bat
+2) cation
Answer:
They all have a choloride(CI-1) ion
Explanation:
The balanced chemical equation for the conversion of nitrogen to ammonia is:2N₂(g) + 3H2(g)2NH3(g): Which of the following statements concerning this chemical equation is/are correct?
1. In a 22.4 L container at standard temperature, 2 atm of nitrogen gas will react with 3 atm of hydrogen gas to produce 2 atm of ammonia gas.
2. At standard pressure and temperature, 22.4 L of nitrogen gas will react with 22.4 L of hydrogen gas to produce 22.4 L of ammonia gas.
3. At standard pressure and temperature, 44.8 L of nitrogen gas will react with 67.2 L of hydrogen gas produce
22,4 L of ammonia gas
Answer:
At standard temperature and pressure, 44.8
Explanation:
help please I'll mark you as a brainliest promise.
Answer:
Law of the Sea Treaty
LOST Local Option Sales Tax (special purpose tax)
LOST Linux One Stanza Tips
LOST Liberty Owners Special Team
LOST Looking Over Strange Terrain :-)
LOST Line Of Sight Tasking
Explanation:is this what you meant?
What is the formula unit for an ionic compound?
Answer:
empirical formula
LAST ATTEMPT! Covalent compound naming !
Answer:sad
Explanation:
haaaaan not
Below the time line, list the layers from oldest to youngest
Answer:
F,E,D,C, B, A, G, H, I
Explanation:
I think. It goes bottom to top. the fault probably cause g to happen and maybe h but mattering on what caused what I am not positive
1. List the ketose carbon(s) that is(are) reduced with NaBH4.
Answer:
ehh im nit sure but here!
Explanation:
