What is a model and why do scientist use them?
Answers
Answer: In science, a model is a representation of an idea, an object or even a process or a system that is used to describe and explain phenomena that cannot be experienced directly. Models are central to what scientists do, both in their research as well as when communicating their explanations.
(hope this helps you ^^)
Related Questions
1. What is the potential energy of a 8 kg ball that is at a height of 20 m?
2. What is the potential energy of a 3 kg ball that is on the ground?
3. What is the potential energy of a 5 kilogram ball that is 24 m from the ground?
PLEASE HELP 8 grade
Answers
Answer:
1. 1568 J
2. 0 J
3. 1176 J
Explanation:
PE = mgh
(PE = Potential Energy) = (m = mass)(g = gravitational force which is 9.8)(h = height)
1. (3)(9.8)(20) = 1568 J
2. PE = (3)(9.8)(0) = 0 J
3. (5)(9.8)(24) = 1176 J
Identify the two elements in the third row of the periodic table that have 2 unpaired electrons. Draw orbital diagrams for the 3 s and 3p orbitals to justify your answer.
Answers
The two elements in the third row of the periodic table that have 2 unpaired electrons are aluminum (Al) and phosphorus (P). The orbital diagrams for the 3s and 3p orbitals can be used to justify this answer.
The 3s orbital can hold a maximum of 2 electrons. In the case of aluminum, the electron configuration is 1s² 2s² 2p⁶ 3s². This means that the 3s orbital in aluminum is fully filled with 2 electrons. The 3p orbitals, on the other hand, can hold a maximum of 6 electrons. In the case of phosphorus, the electron configuration is 1s² 2s² 2p⁶ 3s² 3p³. This means that the 3s orbital in phosphorus is fully filled with 2 electrons, and there are 3 unpaired electrons in the 3p orbitals.
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consider the phase diagram shown here. a sample of the substance in the phase diagram is initially at 120 oc and 925 mmhg. what phase transition occurs first when a substance increases temperature at constant pressure?
Answers
The phase transition which occurs when a substance increases temperature at constant pressure is solid to liquid. The correct option is A.
It can be seen in the attached diagram that when the substance is at 120 degrees C and 925 mmHg, it is in the solid phase. Then, if we increase the temperature while keeping the pressure as constant, it will change to the liquid phase.
How do we know on a phase diagram in what phase a substance is?The lines represent the combinations of pressures and temperatures where two phases can exist in equilibrium. In another words, these lines show phase change points. The line divides the solid and gas phases, defines sublimation (solid to gas) and deposition (gas to solid).
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Although part of your question is missing, you might be referring to this full question: Consider the phase diagram shown here. A sample of the substance in the phase diagram is initially at 120 degrees C and 925 mmHg. What phase transition occurs when a substance increases temperature at constant pressure?
a) solid to liquid
b) liquid to gas
c) solid to gas
d) liquid to solid
The VSEPR model is used mainly to do what
Answers
Why Do Some Things Stop While Others Keep Going?
Answers
Answer:because they run out of energy when it is transferred and to other objects, or their kinetic energy
Explanation:
: Which type of line is shown on the map? isobar
isotherm
radar
humidity
Answers
Answer:
isobar
Explanation:
edge 23
if 140cm3 of methane diffuse into air in 72 sec,how long will it take 210cm3 of sulphur dioxide to diffuse under the same condition ?
Answers
Answer:
time for sulphur dioxide to diffuse is 221.05 secs
The time for sulphur dioxide to diffuse is 108 sec.
Which gas diffuses twice quickly as SO2?Sulfur dioxide has a molecular weight of sixty-four and as a result, the square root is 8. since its inversely proportional, on the way to diffuse two times as fast, the rectangular root of the molecular weight should be 4, and subsequently the molecular weight might be 16. So the solution is methane (CH4).
Which gases diffuse the fastest?The charge of diffusion for a gas is inversely proportional to the rectangular root of its molecular mass (Graham's law). The gasoline with the lowest molecular weight will effuse the fastest. The lightest, and consequently fastest, fuel is helium.
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glyphosate is a common compound found in many herbicides. why was it thought to have no effect on human health before recent scientific studies?
Answers
Glyphosate was initially thought to have no effect on human health because it primarily targets enzymes found only in plants and bacteria, not humans.
Additionally, the compound was believed to have a low toxicity level and was considered to be safe when used according to the labeled instructions.
However, recent scientific studies have suggested potential health risks associated with glyphosate exposure, including links to cancer and other health issues.
These studies have prompted further investigation and controversy surrounding the safety of glyphosate in herbicides.
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Which characteristic does lithium, carbon and fluorine have in common:
1. They belong to the same group
2. They have the same number of valence electrons
3. They are all non-metals
4. Their atoms have the same number of energy levels
Answers
Answer:
I think the answer is
2) They have the same number of valence electrons
the third law of thermodynamics describes the entropy of a: select the correct answer below: solid liquid gas all of the above
Answers
The third law of thermodynamics describes the entropy of a: solid.
The third law of thermodynamics states that the entropy of a pure crystalline substance approaches zero as the temperature approaches absolute zero (0 Kelvin or -273.15 degrees Celsius). This law implies that at absolute zero, a perfectly ordered and pure crystalline solid will have zero entropy.
The third law of thermodynamics is not specific to liquids or gases but applies to solids. In a solid, the molecules are highly ordered and have fixed positions in a regular lattice structure. As the temperature decreases towards absolute zero, the thermal motion of the molecules reduces, and the system becomes more ordered, resulting in a decrease in entropy.
In contrast, liquids and gases have higher entropy compared to solids at absolute zero because their molecules have more freedom of movement and are not as tightly arranged. Therefore, the third law of thermodynamics specifically addresses the entropy of solids and does not apply to liquids or gases.
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Proteins have what charge on their carboxyl terminals at physiological pH?
-Negative
-Zero
-Positive
-Not enough information to determine
Answers
At physiological pH, proteins carry a negative charge on their carboxyl terminals. The carboxyl group (-COOH) of an amino acid in a protein will be largely deprotonated at physiological pH, which is around 7.4.
Proteins at physiological pH are they negatively charged?At physiological pH, the side chains of many biological molecules, including proteins, include functional groups that are both positively and negatively charged. At pH values below their pI, proteins have a net positive charge, while at pH levels above their pI, they have a net negative charge.
At physiological pH, which amino acids have a net negative charge?Aspartic acid and glutamic acid are two amino acids that are negatively charged at physiological pH (between 7.35 and 7.45).
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linear polystyrene has phenyl groups that are attached to alternate, not adjacent, carbons of the polymer chain. refer to the answer to question four (4) to explain the mechanism basis for this fact
Answers
The mechanism of the polymerization reaction, more precisely the characteristics of the monomer and the reaction circumstances, can be used to explain why phenyl groups in linear polystyrene are bonded to alternate, not neighbouring, carbons of the polymer chain.
Styrene (C8H8), a vinyl monomer, is used in the polymerization step that creates polystyrene. A free radical initiator is often employed to start the reaction and spread the growth of the polymer chain in a conventional free radical mechanism. Each styrene monomer's vinyl group (CH=CH2) adds to the vinyl group of another styrene monomer throughout the polymerization process. As a result, a linear chain of repeating units connected by covalent bonds is created. The vinyl group of the styrene monomer is joined to the phenyl group (C6H5) in the case of polystyrene. As a result, during the polymerization process, the phenyl group is absorbed into the polymer chain. The phenyl groups in the polystyrene chain are situated at alternate carbons because they are joined to the vinyl group, which is situated at a different carbon in the styrene monomer. This is due to the head-to-tail nature of the polymerization reaction, in which the vinyl group of one monomer combines with the vinyl group of another monomer in a way that causes the phenyl groups to be arranged along the polymer chain in an alternating pattern. Consequently, in linear polystyrene, the location of the phenyl groups is a result of the styrene monomer's makeup and the polymerization reaction's process.
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does lithium lose or gain valence electrons? and how much?
Answers
Argon has a pressure of 34.6 atm. It is transferred to a new tank with a volume of 456 L and pressure of 2.94 atm. What was the volume of the original container?
Answers
Answer:
38.75 L
Explanation:
From the question,
Applying Boyles Law,
PV = P'V'....................... Equation 1
Where P = Original pressure of the Argon gas, V = Original Volume of Argon gas, P' = Final pressure of Argon gas, V' = Final Volume of Argon gas.
make V the subject of the equation
V = P'V'/P.................... Equation 2
Given: P = 34.6 atm, V' = 456 L, P' = 2.94 atm.
Substitute these values into equation 2
V = (456×2.94)/34.6
V = 38.75 L
Which element has 16 neutrons, 15 protons, and 15 electrons?
Answers
Answer:
phosphorus
Explanation:
Answer:
phosphorus
Explanation:
phosphorus has to lose electrons
Which type of molecule speeds up chemical reactions in living things?
Answers
Protein molecule acting as enzymes speeds up chemical reactions in living things.
Enzymes are proteins that help speed up metabolism, or the chemical reactions in our bodies. They build some substances and break others down. All living things have enzymes. The enzyme is not destroyed during the reaction and is used over and over.
Our bodies naturally produce enzymes. But enzymes are also in manufactured products and food.
Without enzymes, many of these reactions would not take place at a perceptible rate. Enzymes catalyze all aspects of cell metabolism.
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If good Z has an income elasticity of 1.0, then demand for good Z is income __________ and the good is __________.
Answers
If good Z has an income elasticity of 1.0, then demand for good Z is income unit elastic and the good is normal, option E.
The pricing of some items are particularly inelastic, according to economists. In other words, neither a price decrease nor an increase in price significantly affect demand. For instance, the price-elasticity of demand for petrol is low. Drivers, as well as airlines, the trucking sector, and practically every other buyer, will continue to make as many purchases as necessary.
It is not unexpected that marketing experts are really interested in this idea. Even yet, it may be argued that their main objective is to increase inelastic demand for the goods they promote. They accomplish this by finding a significant distinction between their items and any others on the market.
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Complete question:
If good Z has an income elasticity of 1.0, then demand for good Z is income __________ and the good is __________.
a. inelastic; normal
b. inelastic; inferior
c. elastic; normal
d. elastic; inferior
e. unit elastic; normal
If a car rolled down a 20 meter ramp, continued rolling at the bottom and eventually came to a stop 15 meters later, what is the car's displacement? What is the car's distance traveled?
Answers
The car's displacement is 5 m downwards and the distance traveled is 5 m.
What is displacement of the car?
The displacement of the car is calculated as follows;
The displacement is the change in position of the car.
D = Δx
D = X2 - X1
D = 20 m - 15 m
D = 5 m downwards
Distance traveled by the carThe distance is path covered, and it has no direction.
Distance = 20 m - 15 m = 5 m
Thus, the car's displacement is 5 m downwards and the distance traveled is 5 m.
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How many electrons are present in an atom in which the first and second shells and the 3s subshell are filled?.
Answers
Explanation:
Any orbital can hold a maximum of 2 electrons with opposite spin. The first shell has one 1s orbital and holds 2 electrons. The second shell holds 8 electrons; 2 in a 2s orbital and 6 in three 2p orbitals. The third shell holds 18 electrons; 2 in a 3s orbital; 6 in three 3p orbitals; and 10 in five 3d orbitals.
In an atom which contains all the shells up to 3s filled, there will be 12 electrons.
According to the Aufbau principle, the s sub-shell can contain 2 electrons and the p sub-shell can contain 6 electrons.
The atom in which the shells up to 3s are filled, must have 1s, 2s, 2p and 3s orbitals filled.
Therefore, the total number of electrons present in the atom = number of electrons present in 1s + number of electrons in 2s + number of electrons in 2p + number of electrons in 3s.
Total number of electrons in the atom = 2 (electrons from 1s) + 2 (electrons from 2s) + 6 (electrons from 2p) + 2 (electrons from 3s).
Total number of electrons in the atom = 12
So, an atom which has all the shells up to 3s sub-shells filled contains 12 electrons.
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Home can use ____to distribute warm air from a sunroom
Answers
Answer:
Solarpannels? I honestly don't know I'm just trying to be helpful.
As an optional extension, design an experiment to determine from equations 2 and 4 (i) z, the order with respect to naoh and (ii) k, the rate constant
Answers
During this set of experiments we will be working with two members of The Triphenylmethane dyes family, crystal violet and fuchsine. Upon Reaction With NaOH the conjugation gets disrupted and the color is lost.
The reaction between crystal violet and NaOH is the following:
CV+ + OH –(aq) ----------> CVOH
(crystal violet) (hydroxide)
The rate law for reaction (1) is of the form: rate = k [CV+] m[OH–] n , Where k Is the rate constant for the reaction m is the order with respect To crystal Violet (CV+) n is the order with respect to the hydroxide ion.
From these experiments you will be able to obtain the value of the rate Constant k and the complete rate equation.
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Potassium acid phthalate, KHC8H4O4, or KHP, is used in many laboratories, including general chemistry laboratories, to standardize solutions of base. KHP is one of only a few stable solid acids that can be dried by warming and weighed in air. A 0.3031 g sample of KHC8H4O4 reacts with 36.46 mL of a NaOH solution in a titration. What is the molar concentration of the NaOH
Answers
The molar concentration of NaOH solution is 0.0992 M.
The balanced chemical equation of the reaction between KHP and NaOH is KHP + NaOH → NaKP + H2O. From the equation, one mole of NaOH reacts with one mole of KHP. Therefore, the moles of NaOH used in the reaction can be calculated using the equation: n = m/M where, n = number of moles, m = mass of KHP, and M = molar mass of KHP. The molar mass of KHP is 204.22 g/mol. n = 0.3031 g / 204.22 g/moln = 0.001483 mol.
The molar concentration of NaOH can be calculated using the formula: Molarity = n / V where, V is the volume of NaOH used in the reaction. V = 36.46 mL = 0.03646 L. Molarity = 0.001483 mol / 0.03646 L. Molarity = 0.0406 M or 0.0992 M (rounded to four significant figures). Therefore, the molar concentration of NaOH solution is 0.0992 M.
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How many moles of sodium atoms are in 6. 80 x 1024 molecules of Na3PO4
Answers
The number of moles of sodium atoms in a given quantity of sodium phosphate (Na₃PO₄), consider the stoichiometry of the compound. In 6.80 x 10²⁴ molecules of Na₃PO₄, there are 2.04 x 10²⁵ sodium atoms.
The chemical formula of sodium phosphate is Na₃PO₄, indicating that each formula unit of Na₃PO₄ contains three sodium (Na) atoms. Therefore, we can calculate the number of moles of sodium atoms by multiplying the number of molecules of Na₃PO₄ by the ratio of sodium atoms to molecules in the compound.
Given that there are 6.80 x 10²⁴ molecules of Na₃PO₄, we can set up the following calculation:
Number of moles of sodium atoms = (6.80 x 10²⁴ molecules Na₃PO₄) x (3 moles Na / 1 mole Na₃PO₄)
Using the stoichiometry, we find that there are 3 moles of sodium atoms for every 1 mole of Na₃PO₄. Therefore, the number of moles of sodium atoms is 2.04 x 10²⁵ moles.
Note that we multiply the number of molecules of Na₃PO₄ by 3 moles Na / 1 mole Na₃PO₄ to account for the three sodium atoms present in each formula unit of Na₃PO₄.
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The ph of an aqueous solution of 0.215 m potassium nitrite, kno2 (aq), is . this solution is:_______
Answers
The pH of an aqueous solution of 0.215 M potassium nitrite, KNO2 (aq), is 8.10. This solution is basic.
pH stands for potential of hydrogen. It is a measure of the acidity or basicity of an aqueous solution on a scale of 0 to 14. Acids are defined as having a pH less than 7, whereas bases are defined as having a pH greater than 7. A pH of 7 indicates a neutral solution, which is neither acidic nor basic.
KNO2 is the chemical formula for potassium nitrite. It is a white crystalline salt with a slightly salty and bitter taste. It's an important inorganic compound that's utilized as a food preservative in the meat industry. KNO2 is also employed as a reducing agent in the manufacturing of dyes and other chemicals, as well as a fumigant and herbicide.
Therefore, the pH of KNO2 (aq) solution is 8.10. The solution is basic.
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#7) How many waves are in this picture?
Answers
Answer:
4
Explanation:
Answer:
B.
Explanation:
I don't know much about this subject, but it seems that a wave is when the line is above the line in the middle.
How many outermost electrons do lithium and potassium have
Answers
Answer:
Lithium = 3 electrons (Neutral atom)
Potassium = 19 electrons
Correct Question:-
How many outermost shell/orbit contains electrons do lithium and potassium have.
Lithium Atomic number - 3
Ans :- 1 electron
(K -2 , L - 1)
potassium Atomic number - 19
Ans :- 1 electron
(K - 2 , L - 8 , M - 8, N -1)
How does peer review affect research?
A. Experimental results will be trusted by the scientific community
only if they have been peer-reviewed.
B. Experimental results will be published only before they have been
peer-reviewed.
C. An experiment will not be repeated by others if it has been peer-
reviewed.
O D. Experimental results are possible only if they have been peer-
reviewed.
Answers
Answer:
A: Experimental results will be trusted by the scientific community
only if they have been peer-reviewed.
Explanation:
It is NOT C as I have tried it, it did not work and makes no sense.
What are some ways we can measure how much energy a substance has?
Answers
The sum of all an object's atoms and molecules' energies makes up the substance's total energy.
What is a substance's total amount of energy?The sum of all an object's atoms and molecules' energies makes up the substance's total energy. Both the potential energy resulting from the interactions between molecules and the kinetic energy of the particles resulting from the motions of molecules within the material and of atoms inside molecules make up thermal energy.The equation q = m c T , where m is the mass of the sample, c is the specific heat, and T is the temperature change, may be used to determine how much heat is acquired or lost by a sample (q).
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You fill a balloon with 2.50 moles of gas at 29°C at a pressure of 1.60 atm. What is the volume of
the balloon?
15.9 L
22.4L
3.72 L
38.7L
Answers
Answer:lol sorry for that but I don’t know
Explanation:free trial date
Okay
What does a coefficient tell you?
Answers
The coefficient tells you how many molecules of that substance there is.