→ Takli
Takli is a small support style spindle. Takli is a perfect tool for spinning cotton, and this are used too to spin fibers, cotton, cashmere, and silk etc. Takli is known as handspindle. And it is the simplest device for spinning.→ Charkha
Charkha is a device for spinning thread or yarn from fibers etc. This are known as spinning wheel.HAVE A NICE DAY!explain in brief how some bacteria cause tooth cavities
Answer:
because some bacteria change the ph of the teeth and leads to tooth cavitiew
An electrolysis reaction is
A)
exothermic.
B)
hydrophobic.
C)
spontaneous.
D)
non-spontaneous.
Answer:
the electrolysis reaction is a non- spontaneous reaction
Explanation:
Since electrons flow from it, the anode in an electrolytic cell is positive, while the cathode is negative when electrons flow into it. The device functions like a galvanic cell in that direction. In an electrolytic cell, an external voltage is applied and that is what causes a non spontaneous reaction
Which statement is true with respect to standard reduction potentials?
SRP values that are greater than zero always represent a reduction reaction.
SRP values that are less than zero always represent a reduction reaction.
Half-reactions with SRP values greater than zero are spontaneous.
Half-reactions with SRP values greater than zero are nonspontaneous.
Answer:
C). Half-reactions with SRP values greater than zero are spontaneous.
Explanation:
SRPs or Standard Reduction Potentials are characterized as the ability of a probable distinction among the anode and cathode of a usual/standard cell. It aims to examine the capacity of chemicals to reduce themselves.
The third statement asserts a true claim regarding the SRPs(Standard Reduction Potentials) that the 'half-reactions which take place with the SRP possesses the values higher than zero and they are unconstrained.' The other statements are incorrect as they either show the estimation of SRPs more than 0 or display them as being restricted. Thus, option C is the correct answer.
In a aqueous solution of 4-chlorobutanoic acid , what is the percentage of -chlorobutanoic acid that is dissociated
Answer:
Explanation:
Let assume that the missing aqueous solution of 4-chlorobutanoic acid = 0.76 M
Then, the dissociation of 4-chlorobutanoic acid can be expressed as:
[tex]\mathsf{C_3H_6ClCO_2H }[/tex] ⇄ [tex]\mathsf{C_3H_6ClCO_2^-}[/tex] + [tex]\mathsf{H^+}[/tex]
The ICE table can be computed as:
[tex]\mathsf{C_3H_6ClCO_2H }[/tex] ⇄ [tex]\mathsf{C_3H_6ClCO_2^-}[/tex] + [tex]\mathsf{H^+}[/tex]
Initial 0.76 - -
Change -x +x +x
Equilibrium 0.76 - x x x
[tex]K_a = \dfrac{[\mathsf{C_3H_6ClCO_2^-}] [\mathsf{H^+}]}{\mathsf{[C_3H_6ClCO_2H ]}}[/tex]
[tex]K_a = \dfrac{[x] [x]}{ [0.76-x]}[/tex]
where:
[tex]K_a = 3.02*10^{-5}[/tex]
[tex]3.02*10^{-5} = \dfrac{x^2}{ [0.76-x]}[/tex]
however, the value of x is so negligible:
0.76 -x = 0.76
Then:
[tex]3.02*10^{-5}*0.76 = x^2[/tex]
[tex]x=\sqrt{3.02*10^{-5}*0.76 }[/tex]
x = 0.00479 M
∴
[tex]x = \mathsf{[C_3H_6ClCO_2^-] = [H^+]=}[/tex] 0.00479 M
[tex]\mathsf{C_3H_6ClCO_2H }[/tex] = (0.76 - 0.00479) M
= 0.75521 M
Finally, the percentage of the acid dissociated is;
= ( 0.00479 / 0.76) × 100
= 0.630 M
Which of state of matter has no definite shape but does have a definite volume?
A. Liquid
O B. Element
C. Solid
D. Gas
Answer:
A. Liquid .
Explanation:
Hello there!
In this case, according to the given information, it turns possible for us to to infer that the answer is A. Liquid because solids have both definite shape and volume and gases have no definite neither volume nor shape because they depend on the container.
This is this way because the molecules in the liquid are able to vibrate and slowly move around unlike gases and solids whereas molecules readily move and merely vibrate respectively.
Regards!
what will the time for half life of the first order reaction?
Answer:
The half-life of a reaction is the time required for the reactant concentration to decrease to one-half its initial value. The half-life of a first-order reaction is a constant that is related to the rate constant for the reaction: t1/2 = 0.693/k. Radioactive decay reactions are first-order reactions.
Explanation:
The half-life of a reaction is the time required for the reactant concentration to decrease to one-half its initial value. The half-life of a first-order reaction is a constant that is related to the rate constant for the reaction: t1/2 = 0.693/k. Radioactive decay reactions are first-order reactions.
Liquid nitrogen boils at –195.8°C. Express the boiling point of liquid nitrogen in kelvin
Answer:
[tex]\boxed {\boxed {\sf 77.35 \ K}}[/tex]
Explanation:
The Celsius and Kelvin scales are used to measure the temperature of matter. Their scales and unit differences are the same (1 K increase = 1 °C increase), but they have different starting points.
So, the conversion is quite simple and only requires addition because of the different starting points. The formula is:
[tex]T_K = T_C+ 273.15[/tex]
The boiling point of liquid nitrogen is -195.8 °C. We can substitute this value into the formula.
[tex]T_K= -195.8 + 273.15[/tex]
[tex]T_K= 77.35 K[/tex]
The boiling point of liquid nitrogen is 77.35 Kelvin.
give reason why mendeleev's definition of transition elements is no longer acceptable
A molecule of acetone and a molecule of propyl aldehyde are both made from 3 carbon atoms, 6 hydrogen atoms, and 1 oxygen atom. The molecules differ in their arrangement of atoms. How do formulas for the two compounds compare? Both compounds have the same molecular formula, but have unique structural formulas. Both compounds have unique molecular formulas and structural formulas. Both compounds have the same structural formula, but have unique molecular formulas.
Explanation:
The structures of both acetone and propanal are shown below:
In the formula of propanal there is -CHO functional group at the end.
In acetone -CO- group is present in the middle that is on the second carbon.
The molecular formula is C3H6O.
Both have same molecular formula but different structural formulas.
Alkanes are chains of carbon atoms surrounded by hydrogen atoms.
a. True
b. False
Answer:
a. True
Explanation:
Alkanes are chains of carbon atoms surrounded by hydrogen atoms. TRUE.
Alkanes are hydrocarbons, that is, they are organic compounds formed only by carbon and hydrogen. In alkanes, carbon atoms are bonded to each other through single covalent bonds and they are also bonded to hydrogen atoms through the same type of bonds. Alkanes have the general formula CnH2n+2.
When butane reacts with Br2 in the presence of Cl2, both brominated and chlorinated products are obtained. Under such conditions, the usual selectivity of bromination is not observed. In other words, the ratio of 2-bromobutane to 1-bromobutane is very similar to the ratio of 2-chlorobutane to 1-chlorobutane. Can you offer and explanation as to why we do not observe the normal selectivity expected for bromination
Answer:
Bromine radical formation is carried out in the presence of Br₂ and Cl₂ causing the normal selectivity not to be observed ( this causes the difference in activation energy to be reduced )
Explanation:
Why the normal selectivity expected for bromination is not observed
On the basis of selectivity and applying the Arrhenius equation the greater the difference between the activation energies the more the selectivity.
as seen in the formation of primary and secondary radicals in the Bromine radical formation. this difference is caused mainly by the propagation step ( exothermic ) . But the main reason why the the usual selectivity of bromination is not observed is because it Bromine radical formation is carried out in the presence of Br₂ and Cl₂ ( this causes the difference in activation energy to be reduced )
0.50 g of hydrogen chloride (HCl) is dissolved in water to make 4.0 L of solution. What is the pH of the resulting hydrochloric acid solution
Explanation:
Given the mass of HCl is ---- 0.50 g
The volume of solution is --- 4.0 L
To determine the pH of the resulting solution, follow the below-shown procedure:
1. Calculate the number of moles of HCl given by using the formula:
[tex]number of moles of a substance=\frac{given mass of the substance}{its molecular mass}[/tex]
2. Calculate the molarity of HCl.
3. Calculate pH of the solution using the formula:
[tex]pH=-log[H^+][/tex]
Since HCl is a strong acid, it undergoes complete ionization when dissolved in water.
[tex]HCl(aq)->H^+(aq)+Cl^-(aq)[/tex]
Thus, [tex][HCl]=[H^+][/tex]
Calculation:
1. Number of moles of HCl given:
[tex]number of moles of a substance=\frac{given mass of the substance}{its molecular mass}\\=0.50g/36.5g/mol\\=0.0137mol[/tex]
2. Concentration of HCl:
[tex]Molarity of HCl=\frac{number of moles of HCl}{its molar mass}\\=\frac{0.0137 mol}{4.0 L} \\= 0.003425 M[/tex]
3. pH of the solution:
[tex]pH=-log[H^+]\\=-log(0.003425)\\=2.47[/tex]
Hence, pH of the given solution is 2.47.
Does water mess up carbon dating?
Answer:
THE hard-water effect is a recognized source of error in radiocarbon dating. It causes ages to be over-assessed and arises when the material to be dated, such as mollusc shell or plant, synthesizes its skeleton under water and so uses bicarbonate derived in part from old, inert sources.
https://www.nature.com/articles/240460a0#:~:text=THE%20hard%2Dwater%20effect%20is,part%20from%20old%2C%20inert%20sources.
Answer:
In radiocarbon dating, the hard-water effect has been identified as a cause of inaccuracy. It occurs when the item to be dated, such as a mollusk shell or a plant, synthesizes its skeleton underwater and therefore utilizes bicarbonate obtained in part from ancient, inert sources, resulting in the overestimation of ages.
OAmalOHopeO
Classify the following as either solutions or colloids. If a colloid, name the type of colloid and identify both the dispersed and the dispersing phases.
a. glucose in water
b. smoke in air
c. carbon dioxide in air
d. milk
Answer:
a. glucose in water( solution)
b. smoke in air (colloids)
c. carbon dioxide in air (solution)
d. milk( colloids)
Explanation:
A solution is said to be formed when a solute dissolves in a solvent to form a homogeneous mixture. The solute particles are less than 10^-9m in size. Familiar solutions are those where the solute are dissolved in a liquid solvent. When the liquid water, the solution is known as an aqueous solution. A typical example is (glucose in water). In some other cases, the apparent solution of a solute in a solvent is accompanied by a chemical reaction and this is often known as a chemical reaction. A typical example is (carbon dioxide in air).
Colloids are also known as false solutions. Here, the individual solute particles are larger than the particles of the true solution, but not large enough to be seen by the naked eye. When a light beam is placed beside a beaker containing a colloid, the light rays of the beam can be clearly seen. This shows that it exhibits the Tyndall effect while a solution dosent exhibit such.
In a colloid, the liquid solvent is more appropriately know as the DISPERSION medium while the solid solute particles constitute the DISPERSED substance. This can either be solid, liquid or gas.
For example:
--> smoke in air : Dispersion medium is gas while the dispersed substance is solid.
--> milk: Dispersion medium is liquid while the dispersed substance is liquid.
Identify the oxidation half-reaction for this reaction:
Fe(s) + 2HCl(aq) → FeCl2(aq) + H2(g)
A. Fe2+ + 2e → Fe(s)
O B. H2(g) → 2H+ + 2e
O C. Fe(s) → Fe2+ + 2e
O D. 2H+ + 2e → H2(9)
Answer:
Fe(s)->Fe2+2e-
Explanation:
A.p.e.x
The oxidation half-reaction for the given reaction is Fe(s) → Fe²⁺ + 2e⁻ Hence, Option (C) is correct
What is Oxidation reaction ?Oxidation reaction is a chemical reaction which can be described as follows ;
Addition of oxygen Removal of hydrogen Loss of ElectronAddition of electronegative atomRemoval of Electropositive elementIn the given reaction ;
Fe(s) + 2HCl(aq) → FeCl₂(aq) + H₂(g)
Fe at RHS got converted to Fe²⁺ state at LHS which shows the gain of electron by Fe with in the reaction.
Therefore,
The oxidation half-reaction for the given reaction is Fe(s) → Fe²⁺ + 2e⁻ Hence, Option (C) is correct
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Most naturally occurring oxygen (O) is
A. oxygen-18
B. oxygen-15
C. oxygen-17
D. oxygen-16
oxygen 16O
explanation:99.762% of natural abundance
Answer: Oxygen-16
Explanation: Founders Educere answer.
Calculate percent yield when you start with 0.78 grams of camphor and end with 0.23 grams of iso/borneol. The molecular weight of camphor is 152.23 g/mol, and the molecular weight of iso/borneol is 154.25 g/mol.
Answer:
29.1%
Explanation:
First we convert 0.78 g of camphor to moles, using its molar mass:
0.78 g ÷ 152.23 g/mol = 0.00512 mol camphorThen we convert 0.23 g of isoborneol to moles, using its molar mass:
0.23 g ÷ 154.25 g/mol = 0.00149 mol isoborneolFinally we calculate the percent yield:
0.00149 mol / 0.00512 mol * 100% = 29.1%If you were to perform a recrystallization experiment and wanted to form very large crystals of pure substance, what would be the most UNfavorable conditions
The question is incomplete, the complete question is;
If you were to perform a recrystallization experiment and wanted to form very large crystals of pure substance, what would be the most UNfavorable conditions?
A. Fast cooling solution, use of an anti-solvent, rapidly evaporating solution
B. Slowly cooling solution, slowly evaporating solvent
Answer:
Fast cooling solution, use of an anti-solvent, rapidly evaporating solution
Explanation:
Recrystallization is a process of obtaining pure crystals from solution. The procedure involves dissolving the crystals in a solution in which they are soluble at high temperature but insoluble at low temperature.
As the solution cools, the pure crystals are obtained from the solution.
The solvent to be used must be a slow cooling, slow evaporating solvent so that the crystals can be efficiently recovered from solution.
Calculate the percent dissociation of crotonic acid (C,H,CO,H) in a 0.63 mM aqueous solution of the stuff.
Answer:
16%
Explanation:
Crotonic acid : C₃H₅CO₂H
C₃H₅CO₂H ⇄ C₃H₅CO₂⁻ + H⁺
C O O
where : C = C ( 1 - ∝ ) , O = C∝
also: Ka = C∝² / ( 1 - ∝ ) ---- ( 1 )
From Alexa data resource :
Pka = 4.69 , [ Ka = 2.04 * 10^-5 = C∝² / ( 1 - ∝ ) ]
back to equation 1
2.04 * 10^-5 = [ ( 0.63 * 10^-3 ) * ∝² / ( 1 - ∝ ) ] ----- ( 2 )
∴ ∝² / ( 1 - ∝ ) = 3.24 * 10⁻²
Resolving equation above
∝ = 0.1645 = 16.45%
Write the equation for the neutralization reaction in which barium chloride is the salt formed. Show the reaction in which the fully protonated acid reacts with the base to form the salt indicated. Use the smallest integer coefficients possible. (Use the lowest possible coefficients. Omit states of matter.)
Answer:
2 HCl + Ba(OH)₂ ⇒ BaCl₂ + 2 H₂O
Explanation:
In a complete neutralization reaction, an acid reacts with a base to form neutral salt and water. To form barium chloride, hydrochloric acid (acid) reacts with barium hydroxide (base). The balanced chemical equation is:
2 HCl + Ba(OH)₂ ⇒ BaCl₂ + 2 H₂O
Hydrogen is manufactured on an industrial scale by this sequence of reactions: Write an equation that gives the overall equilibrium constant in terms of the equilibrium constants and . If you need to include any physical constants, be sure you use their standard symbols, which you'll find in the ALEKS Calculator.
The question is incomplete. The complete question is :
Hydrogen is manufactured on an industrial scale by this sequence of reactions:
[tex]$CH_3(g) + H_2O(g) \rightleftharpoons CO(g) + 3H_2(g ) \ \ \ \ \ \ \ \ \ \ K_1$[/tex]
[tex]$CO(g) + H_2O(g) \rightleftharpoons CO_2(g) + H_2(g) \ \ \ \ \ \ \ \ \ \ \ \ K_2$[/tex]
The net reaction is :
[tex]$CH_4(g) + 2H_2O(g) \rightleftharpoons CO_2(g) + 4H_2(g) \ \ \ \ \ \ \ \ \ K$[/tex]
Write an equation that gives the overall equilibrium constant [tex]K[/tex] in terms of the equilibrium constants [tex]K_1[/tex] and [tex]K_2[/tex]. If you need to include any physical constants, be sure you use their standard symbols, which you'll find in the ALEKS Calculator.
Solution :
[tex]$CH_3(g) + H_2O(g) \rightleftharpoons CO(g) + 3H_2(g ) \ \ \ \ \ \ \ \ \ \ K_1$[/tex]
[tex]$K_1 = \frac{[CO][H_2]^3}{[CH_4][H_2O]}$[/tex] ...............(1)
[tex]$CO(g) + H_2O(g) \rightleftharpoons CO_2(g) + H_2(g) \ \ \ \ \ \ \ \ \ \ \ \ K_2$[/tex]
[tex]$K_2 = \frac{[CO_2][H_2]}{[CO][H_2O]}$[/tex] ...................(2)
[tex]$CH_4(g) + 2H_2O(g) \rightleftharpoons CO_2(g) + 4H_2(g) \ \ \ \ \ \ \ \ \ K$[/tex]
[tex]$K=\frac{[CO_2][H_2]^4}{[CH_4][H_2O]^2}$[/tex]
On multiplication of equation (1) and (2), we get
[tex]$K_1 \times K_2=\frac{[CO][H_2]^3}{[CH_4][H_2O]} \times \frac{[CO_2][H_2]}{[CO][H_2O]}$[/tex]
[tex]$K_1K_2=\frac{[CO_2][H_2]^4}{[CH_4][H_2O]^2}$[/tex] .................(4)
Comparing equation (3) and equation (4), we get
[tex]$K=K_1K_2$[/tex]
When 4.41g of phosphoric acid (H3PO4) react with 9.25g of barium hydroxide, water and insoluble barium phosphate form. [T/I-7] a. Write and balance the chemical equation.
Answer:
2 H₃PO₄(aq) + 3 Ba(OH)₂(aq) ⇒ Ba₃(PO₄)₂(s) + 6 H₂O(l)
Explanation:
Let's consider the unbalanced equation that occurs when phosphoric acid reacts with barium hydroxide to form water and barium phosphate. This is a neutralization reaction.
H₃PO₄(aq) + Ba(OH)₂(aq) ⇒ Ba₃(PO₄)₂(s) + H₂O(l)
We will balance it using the trial and error method.
First, we will balance Ba atoms by multiplying Ba(OH)₂ by 3 and P atoms by multiplying H₃PO₄ by 2.
2 H₃PO₄(aq) + 3 Ba(OH)₂(aq) ⇒ Ba₃(PO₄)₂(s) + H₂O(l)
Finally, we will get the balanced equation by multiplying H₂O by 6.
2 H₃PO₄(aq) + 3 Ba(OH)₂(aq) ⇒ Ba₃(PO₄)₂(s) + 6 H₂O(l)
Determine whether the reaction will be spontaneous at high temperatures only, at low temperatures only, at all temperatures, or no temperatures. (HINT: Use your chemical sense and your real-world knowledge to predict the signs of delta Hrxn & delta Srxn)
4Fe(s) + 3O2(g) ----> 2Fe2O3(s) [rust]
Circle one:High T, Low T, All T, No T
Answer:
The rusting of iron is spontaneous at low temperatures.
Explanation:
The given chemical reaction is:
4Fe(s) + 3O2(g) ----> 2Fe2O3(s) [rust]
The rusting of iron is a chemical reaction in which iron reacts with oxygen in presence of moisture and forms iron oxide.
This reaction takes place in a faster rate when there is low temperatures in the atmosphere.
When temperature is low, the moisture in the atmosphere is more and hence, rate of rusting is more.
To measure the volume of the blood system of an animal, the following experiment was done. A 1.0-mL sample of an aqueous solution containing tritium, with an activity of dps, was injected into the animal's bloodstream. After time was allowed for complete circulatory mixing, a 1.0-mL blood sample was withdrawn and found to have an activity of dps. What was the volume of the circulatory system
Answer:199mL
Explanation:
Let V ml be the volume of blood in animal.
When 1.0 ml sample is added, total volume becomes V+1.0ml. Its activity is 1000 dpm.
After equilibrium, 2.0 ml of the sample had activity of 10 dpm.
Hence, after equilibrium, the activity of V+1.0 ml of blood sample will be 10/2 (V+1.0ml)=1000dpm
Hence, V=199ml.
the carbon tetrachloride molecule CCI 4 is
Answer:
is a nonpolar molecule with polar bonds
In the process of preparing liquid air for fractional distillation, one fraction will be separated as a solid. What is the chemical name of this fraction?
Answer:
carbon dioxide CO₂
Explanation:
Each gas has a characteristic boiling point. You can separate a random sample of gases by gradually cooling the sample until each component gas liquifies. Some compounds, such as CO₂ never liquify. Instead, they turn directly into solids.
The fraction that will be separated as a solid in the process of liquefaction of air is carbon dioxide.
What is sublimation?
Sublimation is the process of changing the material from its solid to gaseous form without it being liquid, according to physics. An illustration is the evaporation of dry ice, which is frozen carbon dioxide, at typical atmospheric pressure and temperature. Vapour pressure and temperature correlations cause the phenomena.
Food is freeze-dried to preserve it by sublimating water from it while it is frozen under a strong vacuum. Phase is a term used in thermodynamics to describe an amount of matter that is chemically and physically uniform or homogeneous, can be mechanically isolated from a nonhomogeneous mixture, and may consist of a single material or a combination of substances.
The three basic phases of matter are solid, liquid, and gas (vapor), however additional phases, including crystalline, colloid, glassy, amorphous, and plasma, are thought to exist.
Therefore, during the liquefaction of air, the gas that will be separated as a solid is carbon dioxide.
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Calculate the mass percent of KCl in a 0.35 m solution of KCl in water. Assume that the density of water is 1.00 g/mL.
Answer:
Mass percent of KCl is 2.61 %
Explanation:
Our solute is KCl
Our solvent is water
m means molality (moles of solute in 1kg of solvent)
1 kg = 1000 g
0.35 m means that 0.35 moles of KCl are contained in 1000g of solvent
We determine mass of solute: 0.35 mol . 74.55 g/mol = 26.09 g
Total mass of solution is: mass of solute + mass of solvent
26.09 g + 1000 g = 1026.09 g
Mass percent of KCl = (mass of KCl/ mass of solution) . 100
(26.09 / 1026.09) . 100 = 2.61 %
5. A beam of photons with a minimum energy of 222 kJ/mol can eject electrons from a potassium surface. Estimate the range of wavelengths of light that can be used to cause this phenomenon. Show your calculations with units of measure (dimensional analysis) and briefly explain your reasoning.
Answer: The range of wavelengths of light that can be used to cause given phenomenon is [tex]8.953 \times 10^{21} m[/tex].
Explanation:
Given: 222 kJ/mol (1 kJ = 1000 J) = 222000 J
Formula used is as follows.
[tex]E = \frac{hc}{\lambda}[/tex]
where,
E = energy
h = Planck's constant = [tex]6.625 \times 10^{-25} Js[/tex]
c = speed of light = [tex]3 \times 10^{8} m/s[/tex]
Substitute the values into above formula as follows.
[tex]E = \frac{hc}{\lambda}\\222000 J = \frac{6.625 \times 10^{-34}Js \times 3 \times 10^{8} m/s}{\lambda}\\\lambda = 8.953 \times 10^{21} m[/tex]
Thus, we can conclude that the range of wavelengths of light that can be used to cause given phenomenon is [tex]8.953 \times 10^{21} m[/tex].
Write the symbol for every chemical element that has atomic number greater than 70 and atomic mass less than 185.2
Answer:
HF...Ta... W....Lu...
us
Which of the following is a chemical property?
A. Hardness
B. Flammability
C. Malleability
D. Melting point
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