Answer: .84kg
Explanation:
Khan academy
A box slides with an initial speed of 4.0 kg m/s towards a spring on a frictionless horizontal surface. When the box hits a spring with spring constant k = 150 N/m, the spring compresses by 0.30 m.
What is the mass of the box?
Answer: 0.54 kg
The scientist who wrote the universal law of gravitation was
The scientist who wrote the universal law of gravitation was Sir Isaac Newton.
The scientist that wrote the universal law of gravitation was Isaac Newton.
What is the universal law of gravitation?The universal law of gravitation states that every object in this universe attracts every other object around it with a force, whose magnitude is directly proportional to the product of their masses and indirectly proportional to the square of the distance between them.
The universal law of gravitation was first published by the scientist Issac Newton in the year 1687.
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A photon with a wavelength of 397nm is emitted from an electron in energy level 7 of a Hydrogen atom. What is the new energy level of the electron?
Answer:
New energy level is n = 2
Explanation:
ΔE = energy released by e⁻ transition n = 7 to n(final) = - h·c/λ
h = Planck's Constant = 6.63 x 10⁻³⁴ j·s
c = speed of light in vacuum = 3 x 10⁸ m/s
λ = wavelength = 397 nm = 3.97 x 10⁻⁷ m
ΔE = - (6.63 x 10⁻³⁴j·s )(3 x 10⁸ m/s)/(3.97 x 10⁻⁷ m) = - 5.01 x 10⁻¹⁹ joule
Note: this is the transitional energy 'released' by the electron moving from n = 7 energy level to n(final) energy level. As released energy, the system should be represented by an exothermic process hence, the negative value for ΔE = - h·c/λ. The equivalent amount of energy is an absorption of electromagnetic energy (EMR) to promote the electron from n(final) to n = 7 and this would be endothermic as noted with a +h·c/λ .
The Bohr Model of the electron behavior postulates electron transitions by the release of a 'discrete' amount of EMR as emission spectra defined by the expression ...
ΔE = E(final) - E(initial) => E(final) = ΔE + E(initial)
E(n) = positional (potential) energy content of electron while in energy level n and is defined by the expression E(n) = -R(H)/n²
R(H) = Rydberg Constant = 2.18 x 10⁻¹⁸ joules
n = positional energy level (in this case) = 7
E₇ = -2.18 x 10⁻¹⁸ j / (7)² = -4.45 x 10⁻²⁰ j (potential energy of n = 7 electron)
E(final) = ΔE + E₇ = (-5.01 x 10⁻¹⁹ j) + (-4.45 x 10⁻²⁰ j) = -4.455 x 10⁻¹⁹ j
E(final) = -R(H)/n²
=> n = SqrRt[R(H)/E(final)] = SqrRt[(-2.18 x 10⁻¹⁸ j)/(-4.455 x 10⁻¹⁹)] ≅ 2
New energy level is n = 2
how does the water cycle sustains life
plz help! !!
Water is constantly being cycled between the atmosphere, the ocean and the land. This cycling is a very important process that helps sustain life on Earth. When the sun heats water, the water evaporates or changes to water vapor. Water vapor rises and condenses or changes back into liquid water droplets.
Using what you just observe, explain why clouds and precipitation contain freshwater even though much of the water vapor comes from oceans and seas
Answer:
Most of the water doesn't come from the ocean, it comes from fresh water sources
Explanation:
Hope you have a great day :)
Copper extraction symbol equation
Answer:
Fe(s) + Cu2+(aq) ===> Fe2+(aq) + Cu(s)
Answer:
2CuFeS2+2SiO2+4O2→Cu2S+2FeSiO3+3SO2(1)
Explanation:
2CuFeS2+2SiO2+4O2→Cu2S+2FeSiO3+3SO2(1)
Tides are the result of forces exerted on Earth's oceans, mostly by which celestial body?
The Sun
Jupiter
The Moon
Venus
Answer:
Explanation:
The moon
what is the molarity of a solution in which 10.0 g of AgNO3 is dissolved in 5 L of a solution
Answer:
no of moles = given mass/molar mass
no of moles = 10/169.87 =0.058moles
molarity = number of moles of solute/volume of solution in litre
molarity = 0.058/5
molarity = 0.0116
Which step(s) of the greenhouse effect are being most affected by the increases in greenhouse gases, leading to an increase in heat? 1. Solar radiation enters the Earth system and is reflected and absorbed. 2. Absorbed energy is released into the atmosphere as heat. 3. Heat is absorbed by the atmosphere. 4. The atmosphere re-releases heat, warming Earth's surface and lower atmosphere. 1 and 2 2, 3 and 4 1, 2, and 3 3 and 4
Answer:
Answers of the greenhouse effect 1 ,3 and 4
What dose the T-cell attack
Answer:
killer T-cell find and destroy infected cells that have been turned into virus-making factories
HELLLPPPPPP PLSSSSSSS!!!!
what evidence led to the development of the cell theory
A.scientists using microscopes
B.scientists watching bacteria divide
C.scientists seeing organelles inside cells
D.scientists reading a lot of books about cells
which two things cause the orbits of the planets to be the nearby circular
Inertia
gravity
electricity
magnetism
Answer:Gravity and inertia
Which alcohol will behave most like water? C 10H 21OH C 2H 5OH C 7H 15OH C 4H 9OH
Answer:
I believe it is C2H5OH
Explanation:
hopefully it's right
How can a chemical reaction be sped up? Select from the drop-down menu to correctly complete the statement. Add a Choose... that is unaffected by a reaction. the choices are, A: catalyst B: coefficient C: product
Answer:
A: catalyst
Explanation:
In Chemistry, the rate of reaction of chemical elements (reactants) can be sped to produce a chemical compound or elements (products), through the addition of a catalyst that is unaffected by the reaction.
This ultimately implies that, to speed up a chemical reaction, add a catalyst that is unaffected by a reaction.
For example, an enzyme refers to a biological catalyst that is typically used to speed up (accelerate) the rate of a chemical reaction by lowering the activation energy of its reactants.
An enzyme can be defined as a biological catalyst that typically lowers the activation energy of a biological reaction. When the activation energy of a reaction is low, the rate of the reaction would be faster. Therefore, an enzyme speeds or catalyzes the rate of a reaction by lowering its activation energy.
Generally, an increase in temperature increases or speeds up the rate of a reaction while low temperature limits or reduces the rate of a reaction. The optimal temperature for enzymes in the human body is around 37 degrees celsius.
10. A solution contains 130 grams of KNO3 dissolved in 100 grams of water When 3 more grams of KNO3 is added, none of it dissolves, nor do any additional crystals appear. The temperature of the solution is closest to
A.65 Celsius
B. 68 Celsius
C. 70 Celsius
D. 72 Celsius
Answer:
Option B
Explanation:
We will check the solubility graph for potassium nitrate, KNO 3. Based on the graph it can be said that the temperature of solution when 130 grams of KNO3 dissolves in 100 grams of water is near to 65 degree Celsius. Now if three grams of solute is increased then the temperature of the solution will increase by a degree or so and hence the most probable temperature would be 68 degree Celsius.
Hence, option B is correct
Answer:
B. 68 Celsius
Explanation:
Order the terms according to the path followed by oxygen during cellular respiration.
Answer:
Outside air
Nose
Lungs
Bloodstream
Cell
Explanation:
We breathe in oxygen from the outside air in through our nose and it travels to our lungs. Inside our lungs, we have Avioli's that diffuse oxygen into our bloodstream and the bloodstream helps the oxygen travel into our cells.
Hope this helps :)
Respiration is the process of exchange of gases between the cell and atmosphere. The path of respiration involves Outside Air⇒ Nose⇒ Lungs⇒ Bloodstream⇒ Cell.
What is respiration?Respiration is the movement of oxygen from the outside environment to the cells and the removal of carbon dioxide from the cells into the outside environment.
Respiration is of two types depending upon the presence of oxygen:
1. Aerobic Respiration: This takes place in the presence of oxygen
2. Anaerobic Respiration: This takes place in the absence of oxygen.
The path of respiration includes inspiration of outside air into the nose, through the nostrils this air is passed on to the lungs. The alveoli is the site of gaseous exchange in the lungs. In the lungs, oxygen is inspired and carbon dioxide is expired.
The oxygen gas which is inspired by the lungs is dissolved in the blood. Oxygen forms a complex with the hemoglobin protein present in the blood. This blood is then circulated to all the cells and tissues of body. Thus, the oxygen is supplied to all the cells and tissues. The path includes Outside Air⇒ Nose⇒ Lungs⇒ Bloodstream⇒ Cell.
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What does a base release when it is placed in water?
Select one:
a.Chloride ion (Cl-)
b.Hydronium ion (H3O+)
c.Calcium ion (Ca2+)
d.Hydroxide ion (OH-)
Answer:
D - Hydroxide Ion (OH-)
Explanation:
A base provides either hydroxide ions (OH–) or other negatively charged ions that combine with hydrogen ions, reducing their concentration in the solution and thereby raising the pH. In cases where the base releases hydroxide ions, these ions bind to free hydrogen ions, generating new water molecules.
A balloon is placed in a vacuum chamber (a container that all of the air can be pumped out of) and as the air is removed, the balloon increases in size/volume. This is an example of which gas law?
Charles' Law
Boyle's Law
Gay-Lussacs Law
Grant's Law
Answer:
Boyle's Law
Explanation:
"Boyle's law, also referred to as the Boyle–Mariotte law, or Mariotte's law, is an experimental gas law that describes how the pressure of a gas tends to increase as the volume of the container decreases."
-Wikipedia
Write the unbalanced chemical equation for the following reaction:
nitrogen + hydrogen produces
ammonia (NH3)
For the following reactions, predict the products, phases, and balance the chemical reactions,
6)
NaBr (aq) +
H3PO4 (aq) →
4. If 52.0 g of magnesium react with excess hydrochloric acid, how many liters of hydrogen gas can be made at 300 K and 0.970 atm?
Answer: 54.8 Liters of hydrogen gas can be made at 300 K and 0.970 atm
Explanation:
To calculate the moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}[/tex]
[tex]\text {moles of magnesium }=\frac{52.0g}{24g/mol}=2.16moles[/tex]
The balanced chemical equation is:
[tex]Mg+2HCl\rightarrow MgCl_2+H_2[/tex]
According to stoichiometry:
1 mole of Mg gives = 1 mole of [tex]H_2[/tex]
Thus 2.16 moles of Mg give = [tex]\frac{1}{1}\times 21.6=2.16 moles[/tex] of [tex]H_2[/tex]
According to ideal gas equation:
[tex]PV=nRT[/tex]
P = pressure of gas = 0.970 atm
V = Volume of gas = ?
n = number of moles = 2.16
R = gas constant =[tex]0.0821Latm/Kmol[/tex]
T =temperature =[tex]300K[/tex]
[tex]V=\frac{nRT}{P}[/tex]
[tex]V=\frac{2.16mol\times 0.0821Latm/Kmol\times 300K}{0.970atm}=54.8L[/tex]
Thus 54.8 Liters of hydrogen gas can be made at 300 K and 0.970 atm
Someone help me please?
Which of the following best describes the location of an element in the same period as the element tin?
A. Group 14(4A), Period 4
B. Group 16(6A), Period 5
C. Group 14(4A), Period 5
D. Group 13(3A), Period 6
Answer:
b
sorry if wrong
Explanation:
PLSS HELPP Giving brainliest!! Suppose you place the coefficient 4 before H2O. How many atoms of hydrogen and how many atoms of oxygen will the formula have?
Answer: 8 oxygen atoms and 4 hydrogen atoms. Explanation down below.
Explanation: One molecule of oxygen gas is composed of two oxygen atoms (O2). Here there is four atoms of oxygen gas which in total gives eight oxygen atoms. Same ways One molecule of hydrogen gas is composed of two hydrogen atoms (H2), so 2 atoms of hydrogen gas in total gives four hydrogen atoms. As per the formula of water, 2 (H2) and 1(O) to form a water molecule (H2O). Here there are 4 H2, so divide the number of hydrogen atoms by the number needed per water molecule i.e. 4 / 2 = 2. This means 2 water molecules will be produced.
if people are blind can they dream
Answer:
yeah they dream in weird shapes mostly I think. unless they weren't born blind then they dream normally I think
Answer:
Kind of, our dreams refer to what we see, but blind people can't see, they might have dreams what the world might look like
A sample of gas occupies 806 ml at 26.0ºC and 998 mmHg. Find the volume of the gas at STP.
Answer:
966.4mL
Explanation:
Using the combined gas equation as follows:
P1V1/T1 = P2V2/T2
Where;
P1 = initial pressure
P2 = final pressure
V1 = initial volume
V2 = final volume
T1 = initial temperature (K)
T2 = final temperature (K)
According to this question, the following information were provided:
P1 = 998mmHg
P2 (STP) = 760mmHg
V1 = 806mL
V2 = ?
T1 = 26°C = 26 + 273 = 299K
T2 (STP) = 273K
P1V1/T1 = P2V2/T2
998 × 806/299 = 760 × V2/273
804388/299 = 760V2/273
2690.26 = 760V2/273
760V2 = 2690.26 × 273
760V2 = 734440.98
V2 = 734440.98 ÷ 760
V2 = 966.4mL
Write your question here (Keep it simple and clear to get the best answer) Explain why ammonia gas is not collected over water
Answer:
Because of the solubility of ammonia gas in water, it is not collected over water.
Explanation:
Gases prepared in the laboratory are often collected by a technique called water displacement. A bottle is filled with water and placed upside-down in a trough or container of water. The reaction flask is connected to the bottle of water by means of a rubber or glass tubing which is fed under the water bottle . As the gas is produced in the reaction flask, it enters the bottle and displaces the water in it. When the bottle is full of the gas, it is then sealed. The volume of gas in the bottle can be used to determine the amount of gas produced in the reaction. Usually, the gas collected is present in addition to water vapor in the bottle.
Gases that are collected over water must not react with or dissolve in water.
Ammonia gas is very soluble in water. The solubility is due to the readiness with which it forms hydrogen bonds with water to produce aqueous ammonia, NH₃.H₂O.
Aqueous ammonia ionizes partially to produce ammonium ions, NH₄+ and hydroxide ions, OH-. Because of the solubility of ammonia gas in water, it is not collected over water.
What effect does the addition of a catalyst have on a chemical reaction at equilibrium?
A.
It increases the rate of the forward reaction, only.
B.
It increases the rate of the reverse reaction, only.
C.
It increases the rate of both the forward and reverse reactions.
D.
It decreases the rate of both the forward and reverse reactions.
Answer:
C
Explanation:
In the presence of a catalyst, both the forward and reverse reaction rates will speed up equally. :)
A gas occupies 800ml at a temperature of 27C. What is the volume at 132C?
When you remove energy from a substance there will be a *
A. Increase in movement of the molecules
B. Decrease in movement of the molecules
Answer:
b, decrease in movement of the molecules
Explanation:
removing the energy will begin making the molecules lock up and stop moving due to the loss of energy.
hope this helped