To Find :
How many molecules are in 23 moles of oxygen (O₂).
Solution :
We know, 1 mole of any atom/molecule contains 6.022 × 10²³ numbers of atoms/molecules.
So, number of molecules in 23 moles of O₂ are :
[tex]n= 23\times 6.022\times 10^{23}\\\\n =138.506\times 10^{23}\\\\n = 1.385 \times 10^{25}\ molecules[/tex]
Hence, this is the required solution.
PLEASE HELP ASAPPP
A cylinder shaped water tank has a height of 212 ft (6461.76 cm), and is able
to hold 15,000 gallons of water (15,000,000 mL or 15,000,000 cm3). The
volume of a cylinder is expressed by the equation
V = tr^2h
Where V is the volume, r is the radius, and h is the height of the cylinder.
Express the radius (r) in terms of volume (V) and height (h), then determine
the radius of a cylinder water tank (in centimeters) that is filled to capacity.
Answer:
r = [tex]\sqrt{\frac{v}{\pi h} }[/tex]
27.2cm
Explanation:
Given parameters:
Height of tank = 6461.76cm
Volume of water = 15000000cm³
Volume of cylinder = [tex]\pi[/tex] r² h
i. Express radius in terms of volume;
we are to make radius the subject of the expression;
v = [tex]\pi[/tex] r² h
divide both sides by πh
[tex]\frac{v}{\pi h}[/tex] = [tex]\frac{\pi r^{2}h }{\pi h }[/tex]
r² = [tex]\frac{v}{\pi h}[/tex]
r = [tex]\sqrt{\frac{v}{\pi h} }[/tex]
ii.
Radius of the water tank;
r = [tex]\sqrt{\frac{15000000}{\pi x 6461.76} }[/tex] = 27.2cm
HELP ASAP I NEED HELP FAST PLEASE
Kinetic energy is often referred to the energy of
Question 1 options:
A)work
B)mass
C)motion
D)force
)
Question 2 (1 point)
Saving...
Which example has the least kinetic energy
Question 2 options:
A)a 10 kg rock rolling down a hillside at 100 m/s.
B)a 100 kg rock rolling down a hillside at 100 m/s.
C)a 1 kg rock rolling down a hillside at 1 m/s.
D)a 100 kg rock rolling down a hillside at 1 m/s.
Question 3 (1 point)
Saved
The law of conservation of energy states that
Question 3 options:
energy can be created but not destroyed.
energy can neither be created nor destroyed, only change forms.
energy can be destroyed but not created.
Question 3 (1 point)
Saved
The law of conservation of energy states that
Question 3 options:
A energy can be created but not destroyed.
B energy can neither be created nor destroyed, only change forms.
C energy can be destroyed but not created.
D energy never changes
Which is an example of an object increasing its kinetic energy
Question 4 options:
A a train stopped at the station.
B an airplane after landing on a level runway.
C a mouse running faster after spotting a cat.
D a rocket before launch.
Question 5 (1 point)
Identify when an object has a kinetic energy of zero joules.
Question 5 options:
A when an object is no longer in motion.
B when the energy has been destroyed.
C just after a ball it leaves your hand pitching a ball.
D as a pendulum swings downward.
Which is NOT an example of kinetic energy
Question 6 options:
A an elevator moving up to the 3rd floor.
B a skateboard rolling down a hill.
C an arrow after it has hit the target and is at rest.
D a skydiver as they decrease speed after opening their parachute.
1. C
2. D (I’m not entirely sure)
3.energy can neither be created nor destroyed, only change forms.
4. C
5. A
6. C
I’ve researched and tried to answer these questions correctly.
Answer:
1.c
2.a
3.created or destroyed
4.c
5.a
6.c
Explanation:
thanks me later
What is oxidized in a galvanic cell made with silver and nickel electrodes?
A. The silver metal
B. The nickel metal
C. The nickel ions
D. The silver ions
Answer:
B. The nickle Metal
Explanation:
A P E X
PLEASE HELP ME!! THIS IS DUE SOON!!
Determine the number of H2O molecules in 837.4 g of H2O.
Answer in units of molec.
Answer:
Divide 837.4 g by 18.015 g/mol to get moles of H2O
Multiply moles of H2O by 6.022 x 10^23 molecules/mol to get molecules (of H2O in 837.4 g)
Round off your final answer to 4 sig figs.
Thank you and please rate me as brainliest as it will help me to level up
What is the mass, in grams, of 9.01 x 1024 molecules of methanol (CH, OH) ?
Answer:
480.6 g
Explanation:
Given data:
Number of molecules of methanol = 9.01 ×10²⁴
Mass in gram = ?
Solution:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ molecules
9.01 ×10²⁴molecules ×1 mol /6.022 × 10²³ molecules
1.5 ×10¹ mol
15 mol
Mass in gram:
Mass = number of moles × molar mass
Mass = 15 mol × 32.04 g/mol
Mass = 480.6 g
1 point
Sulfur (S) Oxygen (02) water (H2O) and Sodium Chloride (NaCl) are all
examples of pure substances. Which of the following describes all pure
substances *
A pure substance cannot be broken down into simpler substances
O A pure substance consists of only one element
A pure substance has a definite chemical composition
A pure substance is normally found as a solid in room temperature
Answer:
A pure substance has a definite chemical composition
A pure substance has a definite chemical composition in all states. Pure substance can be composed of multiple elements but the composition does not alter in any case.
What are pure substances ?Pure substances are formed either a single component or a combination of more components with a definite composition forming a single phase. Unlike mixtures a pure substance cannot be separated into its components physically.
For example pure water is a pure substance. Water is formed from hydrogen and oxygen atoms in a definite proportion forming a molecular compound that does not alter anyway.
However, salt solution, mixture of two gases etc. are not pure substance. They haven't a definite composition and can be separated by some physical methods. Hence, option c is correct.
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In acidic solution. A 70.0 mL sample of a solution containing Fe2+ requires 70.0 mL of a 0.150 M KMnO4 solution for complete reaction. What is the concentration of the Fe2+ in the original solution?
Answer:
0.75M Fe²⁺
Explanation:
First, we need to balance the redox reaction in acidic medium. Then, we can obtain moles of KMnO4 and with the reaction moles and molarity of the Fe²⁺ solution:
Redox Balance:
Fe²⁺ → Fe³⁺ + 1e⁻
5e⁻ + 8H⁺ + MnO₄⁻ → Mn²⁺ + 4H₂O
___________________________
5Fe²⁺ + 5e⁻ + 8H⁺ + MnO₄⁻ → 5Fe³⁺ + 5e⁻ + Mn²⁺ + 4H₂O
5Fe²⁺ + 8H⁺ + MnO₄⁻ → 5Fe³⁺ + Mn²⁺ + 4H₂OMoles of KMnO₄:
70.0mL = 0.0700L * (0.150mol / L) = 0.0105 moles KMnO₄
Moles and molarity Fe²⁺:
0.0105 moles KMnO₄ * (5 moles Fe²⁺ / 1mol KMnO₄) = 0.0525 moles Fe²⁺
In 70.0mL = 0.0700L:
0.0525 moles Fe²⁺ / 0.0700L =
0.75M Fe²⁺Is selenium tetrafluoride an ionic or covalent bond?
Answer:
Synthesis
The first reported synthesis of selenium tetrafluoride was by Paul Lebeau in 1907, who treated selenium with fluorine:[1]
Se + 2 F2 → SeF4
A synthesis involving more easily handled reagents entails the fluorination of selenium dioxide with sulfur tetrafluoride:[2]
SF4 + SeO2 → SeF4 + SO2
An intermediate in this reaction is seleninyl fluoride (SeOF2).
Other methods of preparation include fluorinating elemental selenium with chlorine trifluoride:
3 Se + 4 ClF3 → 3 SeF4 + 2 Cl2
Structure and bonding
Selenium in SeF4 has an oxidation state of +4. Its shape in the gaseous phase is similar to that of SF4, having a see-saw shape. VSEPR theory predicts a pseudo-trigonal pyramidal disposition of the five electron pairs around the selenium atom. The axial Se-F bonds are 177 pm with an F-Se-F bond angle of 169.2°. The two other fluorine atoms are attached by shorter bonds (168 pm), with an F-Se-F bond angle of 100.6°. In solution at low concentrations this monomeric structure predominates, but at higher concentrations evidence suggests weak association between SeF4 molecules leading to a distorted octahedral coordination around the selenium atom. In the solid the selenium center also has a distorted octahedral environment.
Reactions
In HF, SeF4 behaves as a weak base, weaker than sulfur tetrafluoride, SF4 (Kb= 2 X 10−2):
SeF4 + HF → SeF3+ + HF2−; (Kb = 4 X 10−4)
Ionic adducts containing the SeF3+ cation are formed with SbF5, AsF5, NbF5, TaF5, and BF3.[3] With caesium fluoride, CsF, the SeF5− anion is formed, which has a square pyramidal structure similar to the isoelectronic chlorine pentafluoride, ClF5 and bromine pentafluoride, BrF5.[4] With 1,1,3,3,5,5-hexamethylpiperidinium fluoride or 1,2-dimethylpropyltrimethylammonium fluoride, the SeF62− anion is formed. This has a distorted octahedral shape which contrasts to the regular octahedral shape of the analogous SeCl62−. [5]
Explanation:
Which metal is not required to have its charge specified with roman numerals in the names of ionic compounds it forms?
Will mark you as brainiest!
Aluminum has the larger atomic radius.
silicone is larger than carbon.
Aluminum is larger than silicon
I think silicon is the answer
10. Anna wants to measure the water temperature in the pail. What instrument
she needs to use?
A. Thermometer
C. Barometer
B. Speedometer
D. Anemometer
please answer me
Answer: A. Thermometer
Explanation:
A thermometer is used to measure temperature , while the others measure different things.
Which feature of a map shows the relationship between a distance on a map and that distance on Earth? key scale grid system compass rose
Answer:
Scale is the right answer
Explanation:
The scale is a sentence that relates distance on the map to distance on Earth
The scale of a map represents the relationship between the distances on the map and the actual distances on Earth.
What is map ?A map is a symbolic representation of selected features of a location, typically drawn on a flat surface. Maps present information about the world in a straightforward, visual format. They teach about the world by displaying country sizes and shapes, feature locations, and distances between locations.
The ratio of a distance on Earth to the same distance on a map is known as map scale. On maps, three types of scales are commonly used: written or verbal scales, graphic scales, and fractional scales.
The map scale is the relationship between the distance on a map and the actual distance on Earth.
Thus, The scale of a map represents the relationship between the distances on the map and the actual distances on Earth.
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What field(s) does a moving electron have?
ОА.
electric and gravitational fields
OB. magnetic and gravitational fields
OC. gravitational, electric, and magnetic fields
OD.
electric field only
Answer:
electric field or magnetic field both are same
Explanation:
in an electromagnet the movement of electrons in a wire creates the magnetic field.an electromagnet and the permanent magnet both the magnet have the magnetic fields that can attract the same kinds of materials.
what is an atomic mass unit?
Answer:
A unit of mass used to express atomic and molecular weights, equal to one-twelfth of the mass of an atom of carbon-12. It is equal to approximately 1.66 x 10-27 kg.
Explanation:
Answer:
a unit of mass used to express atomic and molecular weights, equal to one-twelfth of the mass of an atom of carbon-12. It is equal to approximately 1.66 x 10-27 kg.
Explanation:
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Which of the following is a heterogeneous mixture?
A. Oil and Vinegar
B. Air
C. Milk
D. Vinegar in water
Answer:
B
Explanation:
b/c air is not seen by eye
PLS HELPPPPP
Calculate the mass of one water molecule.
1. 4.234 × 10−23 g/molec
2. 5.012 × 10−22 g/molec
3. 2.503 × 10−23 g/molec
4. 2.992 × 10−22 g/molec
5. 2.992 × 10−23 g/molec
6. 1.624 × 10−23 g/molec
7. 4.234 × 10−22 g/molec
Answer:
9vguvvg9uvu
Explanation:
The mass of one mole or 6.02 × 10²³ molecules of water is 18 g/mol. Then, the mass of one molecule of water is 2.99 × 10⁻²³ g/molecule.
What is Avogadro number?The number of atoms that constitutes one mole of a substance is called Avogadro number. It is equal to 6.02 × 10²³. Thus, one mole of every elements contains Avogadro number of atoms.
Similarly, one mole of a compound contains 6.02 × 10²³ number of molecules. Thus, one mole of water contains these much molecules. The mass of one mole of an element is called its atomic mass. Similarly the mass of one mole of a compound is called its molar mass.
Molar mass of water = 18 g/mol
18 g is the mass of 6.02 × 10²³ molecules of water. Hence, the mass of one molecule of water is;
= 18 g/mol/6.02 × 10²³ molecule/mol
= 2.99 × 10⁻²³ g/molecule
Therefore, the mass of one molecule of H₂O is 2.99 × 10⁻²³ g/molecule.
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What is the speed of an electromagnetic wave that has a frequency of 7.8x106
Hz?
Answer:
3. x 10⁸m/s
Explanation:
Given parameters:
Frequency of wave = 7.8 x 10⁶Hz
Unknown:
Speed of the wave = ?
Solution:
All electromagnetic radiation has a speed of 3. x 10⁸m/s in free space.
No matter the frequency and wavelength, they all have the same speed which is the same as the speed of light.
The speed of electromagnetic wave that has a frequency of [tex]7.8 * 10^{6}[/tex] Hz is [tex]3 * 10^{8}[/tex] m/s.
Electromagnetic waves:
Higher-frequency electromagnetic waves have less energy. All electromagnetic waves travel across space at the speed of light which is [tex]3 * 10^{8}[/tex] m/s.
As we know that,
Speed=frequency x wavelength,
It follows that the wavelength will also not change. So the direction, speed, frequency and wavelength of any electromagnetic wave are constant and these properties will not change after emission from a source.
Thus, speed of an electromagnetic wave is fixed and does not change on varying frequencies which is [tex]3 * 10^{8}[/tex] m/s.
OR
The waves travel at the same speed, but the observed frequency depends on any relative motion between the observer and source.
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Predict the products for a reaction between the following:
Ca (s) + AgNO3 (aq) -->
Answer:
Ca + AgNO3 ---> Ca(NO3)2 + Ag
Calcium + silver nitrate ---> Calcium nitrate + silver
also ...reaction type is Single displacement reaction .
hope this answer's your question.
a motorcycle is moving along a road for a distance of 20KM. After 2 hours what is it's the average speed?
Answer:
If it took the motorcycle 2 hours to cover 20km, then the average speed is 10km per hour.
Explanation:
Speed is equal to distance over time. So 20km divided by 2 hours is 10 km per hour.
Please mark brainliest!!! Thanks.
Answer:
96.56063 km/h
Explanation:
two differentiate between north and south poles of magnets
Answer:
A permanent magnet has two different magnetic poles, called the north and south poles. The field lines are inside the magnet. Magnetic poles of the same charge repel each other. Thus, the north pole with another north, the south pole and with another south pole are repelled.
Explanation:
explain the properties of blood that allow it to be a key piece of evidence
Help :) For 100 points
Answer:
6. Color Change.
Production of an odor.
Change of Temperature.
Explanation:
That is the only one I know :)
Answer:
6. 3 things could potentially be, a change in mass, a change in color, or a change in weight. obviously there are more, but these are 3.
I'm sorry I couldn't answer more of these question of yours, I don;t know too much about aluminium :/
May I have brainliest please? :)
How large would the United States (2000 miles across) be?
Answer:
3,717,813
Im not sure, I will get back to you soon
When iron reacts with oxygen, it forms iron oxide, or rust.
Answer:
rust
Explanation:
Use the drop-down menus to answer the questions.
As the amount of surface area increases, what happens to the rate of this reaction?
If the antacid tablet were broken into eight pieces, what would be a reasonable estimate for the time of reaction?
Answer:
the rate is faster, and the time of reaction is 28 seconds
Explanation:
i did the test
Answer:
The rate is faster, 28 seconds
Explanation:
A 2.50 g sample of zinc is heated, then placed in a calorimeter containing 65.0 g of water. Temperature of water increases from 20.00 oC to 22.50 oC. The specific heat of zinc is 0.390 J/goC. What was the initial temperature of the zinc metal sample? (final temperatures of zinc and water are the same)
Answer:
719.83°C
Explanation:
The heat that the sample of Zinc gives is equal to the heat that water is absorbing. That is:
C(Zn) * m(Zn) * ΔT(Zn) = C(H2O) * m(H2O) * ΔT(H2O)
Where:
C is specific heat (Zn: 0.390J/g°C; H2O: 4.184J/g°C)
m is mass (Zn: 2.50g; H2O: 65.0g)
ΔT (Zn: ?; H2O: (22.5°C - 20.0°C = 2.50°C)
Replacing:
0.390J/g°C * 2.50g * ΔT(Zn) = 4.184J/g°C * 65.0g * 2.50
ΔT(Zn) = 697.33°C
As final temperature of Zn is 22.50°C, initial temperature is:
Initial temperature: 697.33°C + 22.50°C
719.83°C
I need help asap, thank you.
Answer: Answer to your question is B. I did a science
Explanation: Test was to see which would dissolve fastest...
Which one is idk what it is giving brainliest
Answer:
B or C
Explanation:
I don't really know sorry.
Answer:
D
Explanation:
I think D I also took the test.
If an atom has an atomic mass of 19 and an atomic number of 9, how many protons, neutrons and electrons does it have?
Answer:
protons = 9
neutrons = 10
electrons = 9 because it is neutral atom
Explanation:
atomic number= protons = 9
atomic mass= protons + neutrons
19= 9 + n
n= 10
what are two ways pollution can get in water
One of the most polluting being city sewage and industrial waste discharge. Indirect sources of water pollution include contaminants that enter the water supply from soils or groundwater systems and from the atmosphere via rain.
Answer:
gas gets dumped is one and the other is dumping trash into water
Explanation: