Which of the following statements is true?
A. Energy can be created, but not destroyed.
B. Some machines are 100 percent efficient.
C. Atomic energy can't be converted into electricity.
D. When work is done, some energy is always "lost" as heat.
Answer:
D
Explanation:
Heat sometimes gets "lost" when work is done
2. A closed system contains 2g of ice. Another 2g of ice are added to the system. What is the final
mass of the system?
Answer:
4
Explanation:
2+2=4
What is the average speed (actually the root-mean-square speed) of a neon atom at 27°C?
Answer:
432m/s
Explanation:
The rms speed (u) is related to the temperature (T) and molecular weight (M) by the expression
u=
M
3RT
u=
40×10
−3
kg/mol
3×8.314J/molK×(27+273.15)K
u=432.2m/s
Hence, the rms speed is 432.2 m/s
hope this is helpful
What are the correct coefficients in order for the equation to be balanced?
how many molecules are in 90g of agno3
Answer:
0.5298072502356179
Explanation:
How do scientists know how reconstruct a fossil?
Scientists will use the structure of existing animal as a model.
Each fossil piece fits together perfectly.
There are labels found in each of the fossil bones.
The location of each fragment found provides clues on how the animal looks.
A, Scientists will use the structure of existing animals as a model :)
Answer:
Scientists will use the structure of existing animal as a model.
Explanation:
-lukelaws
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HCl(aq) + ZnS (s) →
Express your answer as a chemical equation. Identify all of the phases in your answer.
What is an indicator?
Hope it helps you!!
________ is a type of root system.
Stemroot system
Taproot system
Leaf root system
Seedling root system
Why The background of images seemed not same?
Answer:which pictures?
Explanation:show the pictures first
answer: time
Explanation:
well the clouds are moving and the time is different or the seasons also make the background different
Carefully thinking about your choices and their consequences before making a decision shows _____.
Answer:
Decision making
Explanation:
A person who thinks before choosing is a person who makes decisions.
Earth's rotation causes the Coriolis effect. What impact does the Coriolis effect have on global winds?
Answer:
The Earth's rotation means that we experience an apparent force known as the Coriolis force. This deflects the direction of the wind to the right in the northern hemisphere and to the left in the southern hemisphere.
Explanation:
what is relative atomic
Answer:
The relative atomic mass of an element is defined as the weight in grams of the number of atoms of the element contained in 12.00 g of carbon-12.
How many moles of H20 are contained in 4.21 x 1024 molecules of H2O?
O A 2.53 x 1048 moles
OB. 2.34 x 1023 moles
C. 6.99 moles
OD. 0.143 moles
Answer:
C. 6.99 moles
Explanation:
To convert molecules to moles we simply divide the given number of molecules by Avogadro's number, 6.022 x 10²³
Given number of molecules : 4.21 x 10^24
Number of moles : 4.21 x 10^24 / 6.022 x 10²³ = 6.99 moles ( rounded )
The answer is C
Task: Study the pictures above, Write at least five differences of active and inactive volcano based on the picture you've seen and observed above.
Answer:
Explanation:
1. There are fire and flashes at the top of an active volcano. No fire nor flashes for inactive volcano.
2. Smoke and debris come off an active volcano. No smoke nor debris from inactive volcano.
3. Magma flows from top of active volcano. No magma from inactive volcano.
4. There can be snow on top of inactive volcano. Active volcano is too hot for that.
5. There are plants and other wild lives around an inactive volcano.
Which type of molecule is acetone?
A. Amine
B. Ketone
C. Alcohol
D. Aldehyde
Answer: B. Ketone
Explanation: Another name for acetone is propanone, and it is the main ketone as it has the functional group in the middle, a CH3 on each side. Ketones have the C=O functional group.
A chemical reaction yields 3 moles of lithium hydroxide (LiOH).
How many grams of lithium hydroxide are present?
3 g
24 g
48 g
72 g
Answer:
The mass of 1 mole LiOH has been 24 g. Thus, option D is correct.
The mass of a compound present in a mole of sample has been equivalent to the molar mass of the compound. The molar mass of the compound has been the sum of the constituent in a formula unit.
Explanation:
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Answer: 24 g
Explanation:
What is the only way to confirm that a chemical change has taken place?
O A. You can observe a color change.
B. You can see that the mass of material has changed.
C. You can record a temperature change.
D. You can tell that a new substance has formed.
. Why do you think bases are often described as the “opposites” of acids?
they simply don't have the same characteristics
Explanation:
An acid produces a hydroxonium ion as positive which is part of the reason why they are corrosive
Bases are less corrosive which is why they can neutralize an acid to give salt and water
If 16.4 grams of copper (II) bromide react with 22.7 grams of sodium chloride, how many grams of sodium bromide are formed?
The amount of sodium bromide that would be formed from the reaction will be 7.5524 grams
Stoichiometric calculationLooking at the equation of the reaction:
[tex]CuBr_2 + 2NaCl --- > CuCl_2 + 2NaBr[/tex]
The mole ratio of CuBr2 and NaCl is 1:2.
Mole of 16.4 grams of CuBr2 = 16.4/223.37
= 0.0734 moles
Mole of 22.7 grams of NaCl = 22.7/58.44
= 0.3884 moles
Equivalent mole of NaCl = 0.1468 moles
Thus, NaCl is in excess while CuBr2 is limiting.
Mole ratio of CuBr2 and NaBr = 1:1
Mass of 0.0734 mole NaBr = 0.0734 x 102.894
= 7.5524 grams
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Formation of Ionic bond
1. formation of Potassium Sulphide.
Answer:
It can be produced by heating K2SO4 with carbon (coke): K2SO4 + 4 C → K2S + 4 CO. In the laboratory, pure K2S may be prepared by the reaction of potassium and sulfur in anhydrous ammonia.
It's 32°F (0°C) outside under normal atmospheric conditions (1 atm) at a stunt
a
performer's birthday party. There is a huge blue balloon filled with flammable hydrogen
(H2, molar mass = 2.02 g/mol) gas that she plans to safely ignite, causing a massive
explosion. Inside the balloon is 239 g of H2(g).
What is the volume of the balloon, in liters? Round to the nearest whole number.
The volume of the balloon is approximately 2652 liters.
How to determine the volume occupied by the gas in a balloonLet suppose that flammable hydrogen behaves ideally. GIven the molar mass ([tex]M[/tex]), in kilograms per kilomole, and mass of the gas ([tex]m[/tex]), in kilograms. The volume occupied by the gas ([tex]V[/tex]), in cubic centimeters, is found by the equation of state for ideal gases:
[tex]V = \frac{m\cdot R_{u}\cdot T}{P\cdot M}[/tex] (1)
Where:
[tex]R_{u}[/tex] - Ideal gas constant, in kilopascal-cubic meters per kilomole-Kelvin.[tex]T[/tex] - Temperature, in Kelvin[tex]P[/tex] - Pressure, in kilopascalsIf we know that [tex]m = 0.239\,kg[/tex], [tex]R_{u} = 8.314\,\frac{kPa\cdot m^{3}}{kmol\cdot K}[/tex], [tex]T = 273.15\,K[/tex], [tex]P = 101.325\,kPa[/tex] and [tex]M = 2.02\,\frac{kg}{kmol}[/tex], then the volume of the balloon is:
[tex]V = \frac{(0.239\,kg)\cdot \left(8.314\,\frac{kPa\cdot m^{3}}{kmol\cdot K} \right)\cdot (273.15\,K)}{\left(101.325\,kPa\right)\cdot \left(2.02\,\frac{kg}{kmol} \right)}[/tex]
[tex]V = 2.652\,m^{3}[/tex] ([tex]2652\,L[/tex])
The volume of the balloon is approximately 2652 liters. [tex]\blacksquare[/tex]
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4. What are the correct coefficients in order for the equation to be balanced?
Answer:
Li: 2
H2O: 2
LiOH: 2
H2: 1
Explanation:
Good luck
B 2. Meena is at the seaside and drops a message in a bottle into the sea. Explain why the bottle floats and will not sink.
Evaluate
0.411+9.9+0.8
and round the answer appropriately.
Express your answer numerically using the appropriate number of decimal places.
( its not 11.111)
Answer:
11.1
Explanation:
the only reason i can think of why it wouldn't be 11.111 is improper rounding and sig figs. so if you round with sig figs it would be 11.1
The sum of the given values 0.411, 9.9, and 0.8 is 11.111 which on approximation gives 11.11.
To round the answer appropriately, we need to consider the desired number of decimal places. In this case, we are asked to express the answer numerically using the appropriate number of decimal places.
The sum of 0.411, 9.9, and 0.8 is:
0.411 + 9.9 + 0.8 = 11.11
Rounded to the appropriate number of decimal places, the answer is 11.11.
The answer is calculated using the appropriate number of decimal places.
Therefore, The sum of 0.411, 9.9, and 0.8 is 11.11.
To know more about the sum:
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7. Radial probability distributions for the 4s orbital of hydrogen has _______ peak(s). a. 0 b. 1 c. 2 d. 3 e. 4
Answer:
3
Explanation:
That's the answer
I hope it helps
What is a mass number (A)?
Answer:
The mass number in a nucleus is the combined number of protons and neutrons, so it's protons and neutrons, and A symbolizes it. So A is the number of masses, which is equal to the number of protons, that is the number of atoms that we symbolized by Z, plus the number of neutrons.
The mass number, also called atomic mass number or nucleon number, is the total number of protons and neutrons in an atomic nucleus. It is approximately equal to the atomic mass of the atom expressed in atomic mass units.
How many moles are in 239 g of iron? Express your answer to three significant figures.
Propane molecular formula?
Answer:
The propane chemical structure, or chemical formula, is three carbon atoms branched with eight hydrogen atoms I.e C3H8
If 70.0g of manganese (IV) fluoride reacts with 70.0g ammonium sulfide, which reactant is
the limiting reactant and how many grams of the excess reactant is left over?
MnF_4(aq)+2(NH_4)_2S(aq)-> MnS_2(s)+4NH_4F(aq)
The limiting reactant would be the ammonium sulfide and the amount of the excess manganese (IV) fluoride would be 1.96 grams
Limiting reactantsFrom the equation of the reaction:
[tex]MnF_4(aq)+2(NH_4)_2S(aq)- > MnS_2(s)+4NH_4F(aq)[/tex]
The mole ratio of [tex]MnF_4[/tex] to [tex](NH_4)_2S[/tex] is 1:2
Mole of 70 g [tex]MnF_4[/tex] = 70/130.93
= 0.53 moles
Mole of 70 g [tex](NH_4)_2S[/tex] = 70/68.154
= 1.03 moles
Equivalent mole of [tex](NH_4)_2S[/tex] = 0.53 x 2
= 1.06 moles
Thus, [tex](NH_4)_2S[/tex] seems to be limiting while [tex]MnF_4[/tex] is in excess.
Excess [tex]MnF_4[/tex] = 0.53 - 1.03/2
= 0.015 mole
Mass of 0.015 mole [tex]MnF_4[/tex] = 0.015 x 130.93
= 1.96 grams
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