The five reasons why knowledge of celestial motion was important to our ancestors are:
NavigationAgricultureTimekeepingReligionAstronomyThe knowledge of celestial motion was important to our ancestors for the following reasons:Navigation: They needed to Understand the motion of celestial bodies, such as the sun, moon, and stars, which allowed early humans to navigate at sea and on land.Agriculture: They needed the Knowledge of celestial motion was used to create calendars and predict seasonal changes, which was crucial for planting and harvesting crops.Timekeeping: They Observed the movement of celestial bodies which was used to create accurate timekeeping devices, such as sundials and water clocks.Religion: Most of the ancient cultures associated celestial bodies with gods and goddesses, and understanding their motion was important for religious ceremonies and predictions.Astronomy: By studying the motion of celestial bodies, ancient astronomers were able to gain a greater understanding of the universe, and develop theories about the nature of the cosmos.Learn more about celestial motion on
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A 50.7 g meta l ro d is hea'ted t o 92. 3 degree s Celsius. I t is adde d t o a calorimete r fille d wit h 25.O g o f wate r a t 23. 0 degree s Celsius. Wha t is th e fina l temperatur e o f th e mixture
Answer:
Can you be more clear with your question
A 25. 00 ml sample of acetic acid containing phenolphthalein indicator is titrated with 0. 1067 m naoh. The solution changes color after 30. 07 ml naoh has been added. What is the concentration of the acetic acid before titration?.
The concentration of the acetic acid before titration is 0.128M
For weak acid and strong base titration-
Moles of acetic acid = moles of NaOH
Given concentration of NaOH = 0.1067M
Volume of NaOH = 30.07ml = 0.03007L
Using the formula, Concentration = Moles/Volume
Moles of NaOH = concentration X volume = 0.1067 X 0.03007 = 0.0032
Therefore, moles of acetic acid = 0.0032mole
Using the formula, Concentration = Moles/Volume
Concentration of acetic acid = 0.0032/0.025 = 0.128M
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A positive correlation ______ a causal link, and a negative correlation ______ a causal link.
A. does not necessarily indicate, does not necessarily indicate
B. does not necessarily indicate, always indicates
C. always indicates, does not necessarily indicate
D. always indicates, always indicates
A positive correlation does not necessarily indicate a causal link, and a negative correlation does not necessarily indicate a causal link; option A.
What is a correlation?A correlation is a relationship that exists between two variables.
A positive correlation indicates a direct relationship while a negative correlation shows an inverse relationship.
However, a positive correlation does not necessarily indicate a causal link, and a negative correlation does not necessarily indicate a causal link.
In conclusion, a correlation indicates a relationship between two values.
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You want to control the temperature of an enzyme-controlled reaction that is taking place inside a flask. What is the most effective way to keep the reaction at a controlled and steady temperature?
Use of thermostat is the most effective way to keep the reaction at a control temperature.
What is the most effective way to keep the reaction in control?The reaction takes place in a thermostat is the most effective way to keep the reaction at a controlled and steady temperature because thermostat regulates the temperature of that solution which is placed in it. If the temperature goes higher then the extra heat is released from the system.
So we can conclude that use of thermostat is the most effective way to keep the reaction at a control temperature.
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Solid silver bromide and aqueous potassium nitrate are produced by the reaction of aqueous silver nitrate and aqueous potassium bromide .
For the mentioned reaction, the balanced chemical equation is:
KBr (aq) + AgNO3 (s) → KNO3 (aq) + AgBr(s)
The number written in front of the ion, atoms, and molecules in a chemical reaction so that each of the elements on both the sides of reactants and products of the equation gets balanced is known as the stoichiometric coefficient.
What happen when aqueous silver nitrate reacts with aqueous potassium bromide ?From the mentioned balanced equation, the stoichiometric coefficient before KBr is 1, AgNO3 is 1, KNO3 is 1, as well as before AgBr is also 1. Thus, it is clear that 1 mole of potassium bromide reacts with 1 mole of silver nitrate to produce 1 mole of potassium nitrate and 1 mole of silver bromide.
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5. Why is it important to incubate microbe(s) isolated from humans at 37 degrees celsius?
Despite the fact that viruses and ambient bacteria found indoors could both be mesophiles, at 37 degrees Celsius, the temperature of the human body, pathogens would develop more quickly than environmental strains.
A virus would be an infectious submicroscopic creature that only reproduces inside of live cells.
Although bacteria may survive at higher and lower temperatures than humans, they thrive in an environment which really is warm, wet, protein-rich, and pH neutral as well as slightly acidic.
Therefore, Despite the fact that viruses and ambient bacteria found indoors could both be mesophiles, at 37 degrees Celsius, the temperature of the human body, pathogens would develop more quickly than environmental strains.
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Entropy A. has a strong odor B. is a measure of correlation between numeric variables C. is used to calculate information gain D. is a measure of information gain
Correct option:
Entropy is used to calculate information gain.
What is entropy?
Entropy is the measure of data's uncertainty or randomness; the greater the randomness, the higher the entropy. Entropy is used by information gain to make choices. Information will increase if the entropy decreases.Decision trees and random forests leverage information gained to determine the appropriate split. Therefore, the split will be better and the entropy will lower the more information gained.Information gain is calculated by comparing the entropy of a dataset before and after a split.Entropy is a way to quantify data uncertainty. The goal is to maximize information gain while minimizing entropy. The method prioritizes the feature with the most information, which is utilized to train the model.Entropy is actually used when you use information gain.Learn more about entropy here,
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Two balloons, one containing 1.54 L hydrogen gas and the other containing 0.72 L of
helium gas, are at the same pressure and temperature conditions. If the second balloon
contains 0.100 mol of helium, then the mass of hydrogen gas in the first balloon is:
A. 0.43 g
B. 0.22 g
C. 0.094 g
D. 0.047 g
Answer:
A.) 0.43 g
Explanation:
Before you can calculate the mass, you need to find the moles. You can do this by using Avogadro's Law:
V₁ / n₁ = V₂ / n₂
In this equation, "V₁" and "n₁" represent the first balloon's volume and mole value. "V₂" and "n₂" represent the second balloon's volume and mole value. Since you are searching for the first balloon's mole value, you can plug the other values into the equation and simplify to find n₁.
V₁ = 1.54 L V₂ = 0.72 L
n₁ = ? moles n₂ = 0.100 moles
V₁ / n₁ = V₂ / n₂ <----- Avogadro's Law
1.54 L / n₁ = 0.72 L / 0.100 moles <----- Insert values
1.54 L / n₁ = 7.2 <----- Simplify right side
1.54 L = 7.2 x n₁ <----- Multiply both sides by n₁
0.214 = n₁ <----- Divide both sides by 7.2
Now, you can find the mass using the molar mass of the gas. Remember, hydrogen exists as a diatomic molecule.
Atomic Mass (H₂): 2(1.008 g/mol)
Molar Mass (H₂): 2.016 g/mol
0.214 moles He 2.016 g
-------------------------- x ----------------- = 0.43 g H₂
1 mole
A lake experiences episodic acidification, in which the pH drops to 5.0. A scientist studying the lake sees trout and perch disappear from the lake over time. What would be a reasonable explanation for the disappearance of these fish
A reasonable explanation for the disappearance of these fish is the high acidity affecting fish metabolism.
What is the ideal pH for fish?pH is a very important parameter to consider, as it has a direct effect on the metabolism and physiological processes of fish and other aquatic organisms. The pH tolerance range for fish is between 4.0 and 9.0, while the ideal index is between 6.5 and 8.0
With this information, we can conclude that The various fish species differ in terms of the best pH. The pH range between 6.5 – 9.0 is generally recommended for freshwater species. For marine species, the most recommended PH range is between 7.8-8.4.
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Write out the balanced molecular equation for the neutralization of a solution of aqueous barium hydroxide with hydrochloric acid. Be sure to include phase labels in your equation
The balanced molecular equation for this reaction is
2HCl(aq) + Ba(OH)2(aq) ===> BaCl2(aq) + 2H2O(l).
The neutralization of hydrochloric acid and barium hydroxide.
Molecular formula for hydrochloric acid is HCl and barium hydroxide is Ba(OH)2.
Hydrochloric acid and barium hydroxide is aqueous in nature.
HCl have one H+ ion and barium hydroxide has two hydroxide (OH) group.
So, it will take two HCl to neutralize one Ba(OH)2.
Hence, equation for this reaction is
2HCl(aq) + Ba(OH)2(aq) ===> BaCl2(aq) + 2H2O(l).
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What is the relationship between evaporation rate and molecular size of alcohols?
Answer:
larger the intermolecular forces in a compound, the slower its evaporation rate
Explanation:
socratic
A ground test utilizing an auxiliary current electrode and an auxiliary potential electrode is known as the______.
Answer:
The three-point test
Explanation:
The three-point test refers to a ground test utilizing an auxiliary current electrode and an auxiliary potential electrode.
The removal of one or more electrons from a neutral atom results in and
Answer:
The removal of one or more electrons from a neutral atom results in a cation.
Explanation:
When you remove electrons from a neutral atom, the atom becomes more positive. Electrons have a negative charge and the protons inside of the nucleus have a positive charge. When electrons are removed, the positive charges from the protons outweigh the negative charges. This results in a positively charged atom, called a cation.
A certain reaction has an activation energy of 54.0 kJ/mol. As the temperature is increased from 22C to a higher temperature, the rate constant increases by a factor of 7.00. Calculate the higher temperature.
The higher temperature will be:
As the temperature is increased from 22°C to a higher temperature, the rate constant increases by a factor of 7.00. The final temperature will be 271.74K.
What is the activation energy?
Activation energy is defined as the extra energy provided required to activate the molecules to start reacting and forming intermediate and later product.
Arrhenius equations given the relation rate constant and activation energy.
[tex]LnK=Ae^{-\frac{E_a}{RT}\\\\[/tex]
Where,
K= Rate constant
A= Pre exponential factor
[tex]E_a=[/tex] Activation energy
When two rate constants are given [tex]K_1\,[/tex] and [tex]\,K_2[/tex]
[tex]ln\frac{K_2}{K_1}=\frac{E_a}{R}(\frac{1}{T_2}-\frac{1}{T_1})[/tex]
Given,
[tex]T_1[/tex] = 22°C = 295K
Rate constant[tex](K_1)[/tex] increases by a factor of 7,i.e, [tex]K_2=7K_1[/tex]
[tex]E_a[/tex]= 54 kJ/mole = 54000 J/mole
R= 8.314 [tex]J\,mol^{-1}K^{-1}[/tex]
Putting the values,
[tex]ln\frac{K_2}{K_1}=\frac{E_a}{R}(\frac{1}{T_2}-\frac{1}{T_1})[/tex]
ln 7 x 8.31454000 = (1/[tex]T_{2}\\[/tex] - 1/295)
0.299 x [tex]10^{-3}[/tex] + 1/295 = 1/[tex]T_{2}[/tex]
0.00368 = 1/[tex]T_{2}[/tex]
[tex]T_{2}[/tex] = 1/0.00368
[tex]T_{2}[/tex] = 271.74 K
Therefore,
The increase in temperature will change from 295K to 271.74K.
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When the total pressure inside a tennis ball reaches 1013 kPa, the tennis ball will burst. If the ball
originally has a pressure of 405 kPa at room temperature (20°C), at what temperature will the ball burst?
(submit your work)
Answer:
50.0 °C
Explanation:
If all other variables are being held constant, you can find the temperature using Guy-Lussac's Law. The equation looks like this:
P₁ / T₁ = P₂ / T₂
In this equation, "P₁" and "T₁" represent the initial pressure and temperature. "P₂" and "T₂" represent the final pressure and temperature. You can find the missing temperature (T₂) by plugging the given values into the equation and simplifying.
P₁ = 405 pKa P₂ = 1013 pKa
T₁ = 20 °C T₂ = ? °C
P₁ / T₁ = P₂ / T₂ <----- Guy-Lussac's Law
405 pKa / 20 °C = 1013 pKa / T₂ <----- Insert values
20.25 = 1013 pKa / T₂ <----- Divide 20 from 405
20.25 x T₂ = 1013 pKa <----- Multiply both sides by T₂
T₂ = 50.0 °C <----- Divide both sides by 20.25
If your client receives a letter from SilverScript requesting proof of Creditable Coverage, and the client has already submitted proof of creditable coverage with the enrollment application, they can ignore the letter.
If your client receives a letter from SilverScript requesting proof of Creditable Coverage, they can ignore the letter is a false statement
What is Creditable coverage?Creditable coverage is known to be a form of an health insurance, that consist of prescription drug and also other kinds of health benefit plan that is known to meets the minimum amount of qualifications.
Note that the types of creditable coverage plans are group and individual health plans, student health plans, and others.
It is not right to ignore any letter sent to you concerning the case above as it may be vital and as such, the statement of If your client receives a letter from SilverScript requesting proof of Creditable Coverage, and the client has already submitted proof of creditable coverage with the enrollment application, they can ignore the letter is a wrong/false statement.
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Why are pure liquids and solids not included in the reaction quotient or the equilibrium constant expression for a given heterogeneous reaction
Pure liquids and solids at the equilibrium stage:
Pure solids and pure liquids are not included in expressions for the equilibrium constant of heterogeneous equilibria since their concentrations are constant across time. Therefore, including it in our equilibrium expression is not significant.
Equilibrium expression:
When a certain chemical reaction is in equilibrium, the rates of the forward and backward reactions are equal, which means that there is no net change in the concentrations of the reactants and products and that the reaction mixture's composition does not change.
The concentration of solid and liquid:
Solid or liquid concentration,
= No. of Moles/ Volume in L
= Mass/(Volume × molar mass)
= Density/ Molar mass
Pure solids and liquids have constant densities and molar masses at a constant temperature.
Because of this, they have constant molar concentrations, which means that they are not considered in the equilibrium constant for a heterogeneous reaction.
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Which type of bond is not backed by any specific collateral, such as land or equipment?
a) secured bonds
b) debenture bonds
c) equity bond
d) mortgage bonds
Answer:
A
Explanation:
looking at both equity
and mortgage bond fixtures
I would rather say secured bond fit into not being backed by any specific collateral
What is the energy of a photon emitted with a wavelength of 448 nm?
According to the Planck-Einstein relation, the energy of a photon emitted with a wavelength of 448 nm is 4.44 × 10⁻¹⁹ J.
What is a photon?A photon is a particle representing a quantum of light or other electromagnetic radiation. A photon carries energy proportional to the radiation frequency but has zero rest mass.
Step 1. Calculate the frequency of the photon.A photon is emitted with a wavelength (λ) of 448 nm. Given the speed of light (c) is 3.00 × 10⁸ m/s, we can calculate the frequency (ν) of the photon using the following expression.
ν = c/λ
ν = (3.00 × 10⁸ m/s ) / (4.48 × 10⁻⁷ m) = 6.70 × 10¹⁴ s⁻¹
Step 2. Calculate the energy (E) of the photon.We will use the Planck-Einstein relation, being Planck's constant h = 6.63 × 10⁻³⁴ J.s.
E = h × ν
E = (6.63 × 10⁻³⁴ J.s) × (6.70 × 10¹⁴ s⁻¹) = 4.44 × 10⁻¹⁹ J
According to the Planck-Einstein relation, the energy of a photon emitted with a wavelength of 448 nm is 4.44 × 10⁻¹⁹ J.
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Cream of tartar creates a white-purple flame when burned. What can you hypothesize is a component of the cream
Potassium can be a component of the cream.
Why does potassium show white-purple flame when burned?An element's presence can be determined using a flame test. The potassium in cream of tartar is what gives it its white-purple color.
Low ionization enthalpy elements allow the flame to display color. Due to low ionization enthalpy, when an element is heated, its valence electrons are quickly excited to higher orbits and emit light as they return to their original orbit. Salts of potassium emit a white-purple color when ignited. The cream of tartar's chemical formula is KC₄H₅O₆.
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Is nabro3 ionic or molecular?
NaBrO₃ (sodium bromate) is an ionic compound. It consists of a metal (sodium, Na) and a polyatomic ion (bromate, BrO₃⁻).
Ionic compounds are compounds composed of positive and negative ions held together by electrostatic forces. They are formed through the transfer of electrons between atoms, resulting in the formation of positively charged cations and negatively charged anions.
In an ionic compound, the cations are typically metal ions, while the anions are usually nonmetal ions or polyatomic ions. The transfer of electrons occurs from the metal atom(s) to the nonmetal atom(s), resulting in the formation of a crystal lattice structure.
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What's partial negative charge and partial positive charge in an atom? How it's obtained?
Explanation:
However if the two atoms have different affinities for electrons, or electronegativities, then the electrons are more likely to be found closer to the more electronegative atom. In this case, the more electronegative atom gains a partial negative charge, while the less electronegative atom becomes partially positive.
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Which compound has both covalent and ionic bonds? pls give the explanation thx ：）
A NH3
B Na2SO4
C CH3COOH
D NaCl
Answer:
B.) Na₂SO₄
Explanation:
Covalent bonds are bonds which involve electrons being shared between two atoms. These bonds only occur between nonmetals.
Ionic bonds are bonds which involve electrons being given or taken by two atoms. These bonds form between a metal and a nonmetal.
NH₃ contains nitrogen and hydrogen, two nonmetals. Therefore, this molecule only contains covalent bonds.
Na₂SO₄ has both covalent and ionic bonds. The covalent bonds are found within the polyatomic ion, SO₄²⁻. Sulfur and oxygen are both nonmetals, thus covalently combining. The ionic bond forms between the Na⁺ and SO₄²⁻. Sodium (Na) is a metal which wishes to give up electrons to have a complete octet. SO₄²⁻ serves as the anion which it bonds with.
CH₃COOH contains hydrogen, carbon, and oxygen. All of these are nonmetals, thus the only bonds formed are covalent.
NaCl contains sodium, a metal, and chlorine, a nonmetal. Therefore, this compound is held together by an ionic bond.
Which statement is always true about a reversible chemical reaction?
A.
The concentration of reactants is higher than that of the products.
B.
The products can form reactants, and the reactants can form products.
C.
The concentrations of reactants and products are not constant.
D.
The concentration of the products is higher than that of the reactants.
Answer: b
Explanation:
Read the chemical equation.
n2 + 3h2
2nh3
using the volume ratio, determine how many liters of nh3 is produced if 3.6 liters of
h2 reacts with an excess of n2, if all measurements are taken at the same
temperature and pressure? (5 points)
1) 5.4 liters
2) 2.4 liters
3) 1.8 liters
4) 1.2 liters
The volume of [tex]NH_3[/tex] that will be produced is 2.4 liters. The correct option is 2.
Volume ratioThe equation of the reaction goes thus: [tex]N_2 + 3H_2 --- > 2NH_3[/tex]
The ratio of H2 to NH3 is 3:2.
Thus, with 3.6 L of H2, the volume of NH3 that will be produced is:
2/3 x 3.6 = 2.4 liters.
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Which statement is true of the following reaction?
H₂ + O₂H+ + 0²-
O It is balanced for oxidation state and for number of atoms.
O It is not balanced for oxidation state or for number of atoms.
O It is not balanced for oxidation state but is balanced for number of atoms.
OIt is balanced for oxidation state but is not balanced for number of atoms.
Answer: the answer is not c
Explanation: I don't know the correct answer, but I took the test and I know it is not c
Answer:
b is the answer
Explanation:
bc i said so
Which of these is an example of investigating an intensive property?
Oweighing sand in a bag
Omeasuring the length of wire
O determining if a rock is magnetic
Orecording the volume of water in a cylinder
An example of investigating an intensive property is determining if a rock is magnetic. That is option C.
What is intensive property?Intensive property is defined as the property of a substance that doesn't rely on the amount of the substance.
Examples of Intensive property include:
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A known amount of heat is transferred to a sample of iron and the iron raises its temperature by 4.0 degrees Celsius. What would be the temperature increase if the same amount of heat was transferred to the same mass of water
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How much energy will a sample of aluminum gain when it is warmed from 306 K to 419 K? The specific heat capacity of aluminum is 0.897 J/g.K,
and the mass of the sample is 5.00 g.
Answer:
506.81J
Explanation:
H = MC(T1 - T0)
H = 5 × 0.897 × (419 - 306)
H = 5 × 0.897 × 113
H = 506.81 J
As per specific heat of aluminium ,506.81 J of energy is gained by the sample.
What is specific heat capacity?Specific heat capacity is defined as the amount of energy required to raise the temperature of one gram of substance by one degree Celsius. It has units of calories or joules per gram per degree Celsius.
It varies with temperature and is different for each state of matter. Water in the liquid form has the highest specific heat capacity among all common substances .Specific heat capacity of a substance is infinite as it undergoes phase transition ,it is highest for gases and can rise if the gas is allowed to expand.
It is given by the formula ,
Q=mcΔT
For the given example, Q=energy
m=mass=5 g, C=0.897 J/g.K
T₂=419 K
T₁=306 K
substituting in the formula ,Q=5×0.897(419-306)=506.81 J.
Thus, 506.81 J of energy is required.
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Which element is the most reactive?
A. sodium
B. nickel
C. carbon
D. oxygen
Answer:
correct answer is sodium
Explanation:
element is most active in this question is sodium please make me Brilliant to this correct answer