Answer:
If Black Holes Are "Black," How Do Scientists Know They Are There? A black hole can not be seen because strong gravity pulls all of the light into the middle of the black hole. But scientists can see how the strong gravity affects the stars and gas around the black hole.
Explanation:
some examples; 1. Pushing a wheel barrow.
2. Opening or closing a door.
3. Squeezing wet clothes.
4. Gravitational force.
5. Brakes applied to stop a moving vehicle.
6. A football kicked harder that decreases due to the frictional force.
7. Rubbing a glass rod with a silk.
8. Pressure applied on a pin of a notice board.
9. Running
10. Pushing
Supernova or void is another force or phenomenon that cannot be seen directly similar to black holes.Examples of the effects are gravitational force, brakes applied to stop a moving vehicle.
What is force?Force is defined as a cause which is capable of changing the motion of an object. It can cause an object which has mass to change it's velocity. It is also simply a push or a pull . It has both magnitude as well as direction.Hence, it is a vector quantity.
It has SI units of Newton and is represented by'F'.Newton's second law states that force which acts on an object is equal to momentum which changes with time. If mass of object is constant, acceleration is directly proportional to net force acting on an object.
The concepts which related to force are thrust and torque .Thrust increases the velocity of an object and torque produces change in rotational speed of an object.
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How many atoms of oxygen are in 2. 50 moles of so2?
The number of atoms of oxygen are present in 2.50 moles of sulfur dioxide is 30.110 × 10²³.
What is Avogadro's number?Avogadro's number is define as the number of atoms present in one mole of any substance and it is equal to 6.022 × 10²³.
In the 1 mole of SO₂ 2 moles of oxygen are present. So that in 2 moles of SO₂, 2(2.5) = 5 moles of oxygen is present.
No. of atoms of oxygen in 5 moles of oxygen will be calculated as:
No. of atoms = 5 mole × 6.022 × 10²³atoms per mole = 30.110 × 10²³atoms
Hence number of atoms of oxygen is 30.110 × 10²³.
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Which model states that an acid is a substance that contains hydrogen and ionizes to produce hydrogen ions?.
Answer:
The Arrhenius model
Explanation:
The Arrhenius state that an acid is a substance that contains hydrogen and ionizes to produce hydrogen ions in aqueous solution.
Fe +0₂--Fe₂O3
35. What type of reaction is given
Which answer choice best explains why atoms of carbon-14 (c-14) are unstable? atoms of c-14 have too many negatively charged electrons and too few positively charged protons. atoms of c-14 have too many positively charged protons and too few negatively charged electrons. there are 2 more protons than neutrons in the nucleus. there are 2 more neutrons than protons in the nucleus.
The best choice that explains why atoms of carbon-14 (c-14) are unstable is there are 2 more protons than neutrons in the nucleus
What is a stable atom?An atom is said to be stable if the number of neutrons in the nucleus is greater than number of protons in the nucleus, because the the neutrons increases the nuclear force which keeps the atom stable.
Thus, the best choice that explains why atoms of carbon-14 (c-14) are unstable is there are 2 more protons than neutrons in the nucleus.
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Answer:
D. there are 2 more neutrons than protons in the nucleus.
Explanation:
1. How many formula units are contained in 270.2 g of zinc nitrate, Zn(NO3)2?
50 POINTS
Zinc nitrate has 1 molecule of zinc (Zn), 2 molecules of nitrogen (N) and 6 molecules of oxygen (O).
Calculate the molecular mass of zinc nitrate by adding the molecular weights for all molecules in the compound.
Here are the molecular weights for each element:
Zn=65.38 g/mol
N=14.01 g/mol
O=16.00 g/mol
The molecular weight of zinc nitrate is then: 1*(65.38)+2*(14.01)+6*(16.00)=189.40 g/mol.
Using a conversion formula to calculate moles of zinc nitrate:
163.97gZn(NO
3
)
2
∗
189.40gZn(NO
3
)
2
1molZn(NO
3
)
2
=0.866molZn(NO
3
)
2
There are 0.866 moles of zinc nitrate.
Note: These numbers may vary slightly due to the source of the molecular weight data and the number of decimal places used.
How many molecules are in 368 g of potassium hydroxide (KOH)?
Answer: 6.559055381954511
Explanation:
An ecosystem where all organisms have niches and habitats will be
balanced.
unbalanced.
Answer:
balenced.
Explanation:
An ecosystem where all organisms have niches and habitats will be balanced.
What is an ecosystem ?An ecosystem consists of all the organisms and the physical environment with which they interact.
What is a niche ?Niche describes the role an organism plays in a community. A species' niche encompasses both the physical and environmental conditions it requires and the interactions it has with other species.
What is a habitat ?Habitat is the area and resources used by a particular species.
A balanced ecosystem represents a sustainable habitat of interdependent animals, plants, and microorganisms and their environment.
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What occurs as energy is transferred through the radiative zone of the sun? check all that apply. gamma rays are produced. photons are absorbed and reemitted. energy is transferred through the large-scale movement of material. photons are scattered in many directions. energy is released into the photosphere.
Answers:
1) Photons are absorbed by hot gas atoms.
2) Energy is transferred through large-scale movement of material.
3) Energy is released into the photosphere.
The Sun interior is divided into three regions: the inner core, the radiative zone and the convection zone.
The inner core is the central region of the Sun and all solar energy is produced in the core by nuclear fusion.
Radiative zone is around the inner core and in this area energy is transported by radiation.
The convection zone is the outer-most layer of the interior and in this area energy is transported by convection.
During photosynthesis and cellular respiration plus carry out processes that involve both light and energy and chemical energy. Sort each tile into the correct column.
-Used to directly power cell growth
-Used to directly power photosynthesis
-Released through cellular respiration
-Captured by chloroplyll
Chemical energy power cell growth, solar radiation power photosynthesis and is captured by chlorophyll, and carbon dioxide is released through cellular respiration.
Photosynthesis and RespirationDuring photosynthesis, solar radiation is captured by chlorophyll in green plants, and this is used to fix inorganic carbon dioxide and water to produce plant food in the form of carbohydrates.
During respiration, the carbohydrates synthesized via photosynthesis are broken down chemically to extract the energy locked in them. Carbon dioxide is produced as a by-product.
The energy extracted by respiration is used to power metabolic processes in plants.
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How many moles of hydrogen are required to react with 2 moles of oxygen?
Answer:
4 moles of H2
Explanation:
From the equation, twice as many
2 moles of O2 requires 4 moles of H2
1mol of Oxygen requires 2 moles of Hydrogen
Moles of oxygen=2Moles of Hydrogen
2(2)4molesPedro adds 1.25 moles of helium to a balloon that already contained 4.51 moles of helium creating a balloon with a volume of 8.97 liters. What was the volume of the balloon before the addition of the extra gas
Answer:
don't know what u mean by that
Explanation:
so help me
The pressure inside of the chem-101 laboratory is 751 mm Hg. Calculate the pressure in units of atmospheres? (760 mm Hg = 1.00 atm)
751/760 x 1 atm = 0.988 atm
Balance the equation for a half-reaction that occurs in acidic solution. Use e− as the symbol for an electron
The balanced half-reaction equation is [tex]MnO_4^- + 4H^+ --- > MnO_2 + 2H_2O + 3e^-[/tex]
What is a redox reaction?The term redox reaction has to do with a reaction in which there is a loss or gain of electrons. In this reaction, one specie accepts electrons while another species loses electrons.
The balanced half-reaction equation in acid is;
[tex]MnO_4^- + 4H^+ --- > MnO_2 + 2H_2O + 3e^-[/tex]
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Please help!!!
what is the name of pb(no3)2? explain how you determined the bond type and the steps you used to determine the naming convention for the compound.
The cation part is named first in an ionic compound and the anionic part is named with the suffix of ate, id etc. The name of the ionic compound Pb (NO₃)₂ is lead nitrate.
What are ionic compounds?Ionic compounds are formed between metals and nonmetals. Metals are electron rich and can easily lose electrons to form positively charged ions called cations.
Non-metals with electron-deficiency will gain electron from the metals and acquires a negative charge to form anions. The electrostatic force of this negative clouds and positive cloud from the cation is called ionic bonding.
For ionic compounds, the cation or metals are named first. Pb is a metal with two valence electrons and NO₃ group has a negative charge. Thus, Pb donates its two electrons each to each nitrate groups and the anionic part nitrate is named last.
Therefore, the compound name is lead nitrate.
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How many moles is 3.48 g of carbon?
[tex]\text{No. of moles } = \dfrac{\text{Mass of substance(C)} }{\text{Molar mass of substance(C)}}\\\\\\~~~~~~~~~~~~~~~~~~~=\dfrac{3.48}{12}~ \text{mol}\\\\\\~~~~~~~~~~~~~~~~~~~=0.29~ \text{mol}[/tex]
Questlon 2 of 10
Which of these describes a reason why nuclear power is important?
• A. Solar technology can be installed to provide any home with power.
• B. Solar and wind technologies are both "green."
• C. Solar and wind technologies are location specific.
• D. It's important to use "green" energy to protect our environment.
Answer:
c
Explanation:
its the only one with a downside to solar and wind.
Some greenhouse gases, such as fluorocarbons (CFCs, HFCs, PFCs, etc.), are human-made. Others, such as water, methane, and carbon dioxide, are naturally produced. Which type of greenhouse gas (human-made or natural) is more difficult to control and eliminate? Which types are easier? In three to five sentences, provide evidence for your argument.(4 points)
The natural types of greenhouse gases are more difficult to control and eliminate while the human-made type are easier.
What are greenhouse gases?Greenhouse gases are specific type of gases that have the ability to trap and release heat in their bonds.
Greenhouse gases are the cause of global warming, which is the gradual increase in temperature of the Earth's atmosphere.
However, greenhouse gases can either occur naturally or be synthesized artificially. The naturally-occuring greenhouse gases like CO2 are more difficult to control because they are not produced by humans.
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What is the ph of a 0. 571 m solution of hydrosulfuric acid, h2s?
pH is the potential of the hydrogen in the aqueous solution. The pH of the hydrosulfuric acid is 0.6.
What is pH?pH is the hydrogen or the hydronium ion concentration in the aqueous solution. The formula to calculate pH is given as,
[tex]\rm pH = \rm - log [H^{+}][/tex]
Since hydrosulfuric acid is diprotic the concentration of the hydrogen ion will be:
[tex]\begin{aligned} \rm [H^{+}] &= 2 \times 0. 571 \;\rm M \\\\&= 1.142\end{aligned}[/tex]
Now, pH is calculated as:
[tex]\begin{aligned} \rm pH &= \rm - log [H^{+}]\\\\&= \rm - log [1.142]\\\\&= 0.06\end{aligned}[/tex]
Therefore, 0.6 is the pH of the hydrosulfuric acid solution.
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Based on your observations, do you think any of the samples are the same substance?
Yes
Yes
No
No
Explain your answer below.
list the symbols for the noble gases
Answer:here:
Explanation:helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn), and oganesson (Og).
How many grams of nacl are present in 350 ml of a 0. 277 m solution of sodium chloride? a 1. 66 g b 16. 2 g c none of these d 97. 0 g e 5. 67 g
A NaCl solution of 350 mL volume and a concentration of 0.277 M will contain 5.67 grams of the salt.
Mole calculationRecall that:
Mole = molarity x volume.
Also:
Mass = mole x molar mass
Hence;
Mole of 350 mL, 0.277 NaCl = 0.350 x 0.277 = 0.097 moles
Mass of 0.097 moles NaCl = 0.097 x 58.44 = 5.67 grams
Thus, a 350 mL, 0.277 M NaCl solution will contain 5.67 grams of the salt.
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A mixture of helium, nitrogen and oxygen has a total pressure of 821 mmHg. The partial pressure of helium is 105 mmHg, and the partial pressure of nitrogen is 312 mmHg. What is the partial pressure (in mmHg) of oxygen in the mixture?
Answer:
Total partial pressure, Pt = 821 mm Hg
Partial pressure of Helium, P1 = 105 mm Hg
Partial pressure of Nitrogen, P2 = 312 mm Hg
Partial pressure of Oxygen, P3 = ? mm Hg
According to Dalton's law of Partial pressures,
Pt = P1 + P2 + P3
So, P3 = 404 mm Hg
How many total atoms are in one molecule of cobalt hydroxide?
Answer: Hello! I'm Jungkook. Here is your answer.....
1 Atom.
Explanation:
Hope this helps! Anneyong/Bye!
xoxoKookie
What else is produced during the replacement reaction of silver nitrate and potassium sulfate? 2agno3 k2so4 ag2so4 ________ kno3 2kno3 k2 2agno3
When silver nitrate reacts with potassium sulfate, the products would be silver sulfate and potassium nitrate.
Products from reactionsThe reaction between silver nitrate and potassium sulfate is a double replacement reaction that is represented by the following equation:
[tex]2 AgNO_3 + K_2SO_4 --- > Ag_2SO_4 + 2 KNO_3[/tex]
Thus, the products are silver sulfate ([tex]Ag_2SO_4[/tex]) and potassium nitrate ([tex]KNO_3[/tex]).
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Answer:
A
Explanation:
A chemist wants to extract copper metal from copper chloride solution. The chemist places 0.50 grams of aluminum foil in a solution containing 0.75 grams of copper (II) chloride. A single replacement reaction takes place. Which statement explains the maximum amount of copper that the chemist can extract using this reaction?
Unbalanced equation: CuCl2 + Al → AlCl3 + Cu
A. Approximately 0.36 grams, because copper (II) chloride acts as a limiting reactant
B. Approximately 1.8 grams, because copper (II) chloride acts as a limiting reactant
C. Approximately 0.36 grams, because aluminum acts as a limiting reactant
D. Approximately 1.8 grams, because aluminum acts as a limiting reactant
Approximately 0.36 grams of Cu are produced because copper (II) chloride acts as a limiting reactant.
What is an Equation ?A representation of a chemical reaction using symbols of the elements to indicate the amount of substance, usually in moles, of each reactant and product.
Based on the balanced equation of reaction and the reacting masses, approximately 0.36 grams of Cu are produced because copper (II) chloride acts as a limiting reactant.
The amount of copper produced is determined from the balanced equation of the reaction.
The equation of the reaction is given below:
3 CuCl₂ + 2 Al → 2 AlCl₃ + 3 Cu
molar mass of CuCl₂ = 132 g/mol
molar mass of Al = 27.0 g
molar mass of Cu = 64.0 g
moles of aluminium in 0.50 g = 0.50 / 27 = 0.018 moles
moles of CuCl₂ in 0.75 g = 0.75/132 = 0.00568 moles
Therefore, CuCl₂ is the limiting reactant
3 moles of CuCl₂ produces 3 moles of Cu
0.00568 moles of CuCl₂ will produce 0.00568 moles of Cu
Mass of 0.005 moles of Cu = 0.00568 * 64 = 0.36 g of Cu
Therefore, approximately 0.36 grams of Cu are produced because copper (II) chloride acts as a limiting reactant.
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A 78.0 sample of gold at 175°C is put in a foam cup calorimeter with 25.0 g of water at 25.0°C. Calculate the specific heat of the gold if the final temperature is 38.18°C and the specific heat of water is 4.18 J/g°C. Show your work.
Thanks for the help!!
The answer is the specific heat of the gold is 0.129 J/gC .
What is Calorimetry ?It is an experimental method that allows one to calculate the heat change in a chemical process.
Calorimeter is just a reaction vessel. It could be a foam cup, a soda can, or a commercially available bomb calorimeter
Where q represents the heat change in the reaction, the calorimeter and the water. Since you are only measuring temperature, you will need to calculate the heat using it.
The change in heat of the gold is given by:
[tex]\rm q_{gold} = m c_{gold}\Delta T[/tex]
[tex]=78 \times c_{p}\times (175-38.18)[/tex]
The change in heat of the water is given by:
[tex]\rm q_{water} = mc_{p}\Delta T[/tex]
m is the mass of water in the calorimeter in grams,
and delta T is the change in temperature.
where [tex]\rm c_{p}[/tex] is the specific heat of water, which is 4.184 J/gC
mass of water = 25 g of water.
Temperature T₁ = 25°C
Final Temperature = 38.18 °C
Difference between temperature = 13.18 °C
[tex]\rm q_{water} = 25 \times 4.18\times 13.18[/tex]
For a Foam Cup Calorimeter
[tex]\rm q_{water} = q_{cal}\\\\\\\rm 25\times4.18\times13.318 = 78 \times c_{p}\times (175-38.18)\\\\\\On \;solving\; this \;we \;get \;c_{p} = 0.129[/tex]
Therefore the the specific heat of the gold is 0.129 J/gC
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The following flow of energy takes place in one ecosystem: alga → insect → larva flatworm → fish.
Which trophic level has the most energy to pass on to the next?
A) insect larva
B) fish
C) flatworm
D) alga
Answer: D. Alga
Explanation:
How many moles of hydrogen gas would be required to produce 25 moles of H2O?
Answer:
There would be 25 moles
Explanation:
This is the equation for water (synthesis):
2H₂ + O₂ → 2H₂O
Since there are 25 moles of water, the moles of hydrogen gas will have 25 moles.
As the atomic number of elements within Group 2 increases, the metallic character of each successive element
(1) decreases
(2) increases
(3) remains the same
1
How many atoms of carbon would be present in a molecule of CCl4?
A
5
B
1
С
2
D 4
Answer:
There are 5! goodluck,
Explanation:
