Answer:
He is a English chemist physicist and meteorologist. He is best known for the atomic theory
Answer:
John Dalton was a scientist.
Explanation:
Which of the following may suggest a catalyst has been used in a reaction, given the energy diagram for the same reaction without a catalyst?
Which type of river is similar to a mature river, but flows more slowly so has less power to change the landscape? Select one: a. Youthful River b. Mature River c. Old Age River
Answer:
The correct option is;
C. Old Age River
Explanation:
Among the three stages of the development of a river, which are the youthful, mature, and old age stages, the old age river is least dynamic
The water is very slow moving with a low gradient and lesser erosive power to alter the landscape which results in the appearance of flood planes
Examples of old age rivers include, lower Ganges, lower Nile, Indus, and Yellow rivers
Old age rivers are characterized by a broad shape, with a wide flood plane, a very gentle gradient and the water current is low.
Answer:c
Explanation:
old age river
A container initially holds 5.67 x 10^-2 mol of propane and has a volume of V1. The volume of the container was increased by adding an additional 2.95 x 10^-2 mol if propane to the container, so that the container has a final volume of 1.93 L. If the temperature and pressure are constant, what was the initial volume of the container?
Answer:
Initial volume of the container (V1) = 1.27 L (Approx)
Explanation:
Given:
Number of mol (n1) = 5.67 x 10⁻²
Number of mol (n2) = (5.67 +2.95) x 10⁻² = 8.62 x 10⁻²
New volume (V2) = 1.93 L
Find:
Initial volume of the container (V1)
Computation:
Using Avogadro's law
V1 / n1 = V2 / n2
V1 / 5.67 x 10⁻² = 1.93 / 8.62 x 10⁻²
V1 = 10.9431 / 8.62
Initial volume of the container (V1) = 1.2695
Initial volume of the container (V1) = 1.27 L (Approx)
Answer: 1.27 L
Explanation:
First, calculate the final number of moles of propane (n2) in the container.
n2 = n1 + nadded = 5.67 × 10^−2 mol + 2.95 × 10^−2 mol = 8.62 × 10^−2 mol
Rearrange Avogadro's law to solve for V1.
V1 = V2 × n1 / n2
Substitute the known values of n1, n2, and V2,
V1 = 1.93 L × 5.67 × 10^−2 mol / 8.62 × 10^−2 mol = 1.27 L
Na-23 has 12 neutrons. What is it’s atomic number?
Answer:
11 Protons
Explanation:
Na-23 shows the mass of the element as 23. Therefore subtract 12 neutrons from the mass to get # of protons which is = to atomic #.
The atomic number of 23-Na is 11. It can be calculated from the number of protons present in the nucleus of an atom.
The atomic number is a fundamental property of an element and represents the number of protons found in the nucleus of an atom. It uniquely identifies each element on the periodic table. In a neutral atom, the atomic number also indicates the number of electrons present in the atom, as the number of protons and electrons in an atom are equal.
For example, hydrogen has an atomic number of 1, indicating that it has one proton in its nucleus. Oxygen has an atomic number of 8, indicating that it has eight protons in its nucleus.
The atomic number determines the element's position in the periodic table and provides important information about its properties and behavior.
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A substance contains 23.0 g sodium, 27.0 g aluminum, and 114 g fluorine. How many grams of sodium are there in a 102-g sample of the substance? Select one: a. 4.43 g b. 23.0 g c. 14.3 g d. 102 g e. None of these
Answer:
E. None of the above
Explanation:
The volume of a sample of pure HCl gas was 221 mL at 20°C and 111 mmHg. It was completely dissolved in about 50 mL of water and titrated with an NaOH solution; 18.7 mL of the NaOH solution was required to neutralize the HCl. Calculate the molarity of the NaOH solution.
Answer:
[tex]molarity =6.9\times 10^{-3}\ M\\[/tex]
Explanation:
We know that , the reaction of HCl and NaOH is given as follows
[tex]NaOH+HCl=NaCl +H_2O[/tex]
Given that
Pressure = 111 mm Hg
[tex]P=111\times 13.6\times 10^{-3}\times 9.81\times 1000=14.809\ kPa[/tex]
Temperature = 20°C
T=20+273=293 K
Volume= 221 m L
V=0.221 L
Number of moles of HCl is given as follows
[tex]n=\dfrac{P\times V}{R\times T}\\n=\dfrac{0.148\times 0.221}{0.821\times 293}=1.3\times 10^{-4}\ moles[/tex]
From the above reaction we can say that
Number of moles of HCl=Number of moles of NaOH
Volume of NaoH is given as follows
V=18.7 = 0.0187 L
Therefore molarity
[tex]molarity =\dfrac{n}{V_{NaOH}}\\molarity =\dfrac{1.3\times 10^{-4}}{0.0187}=6.9\times 10^{-3}\ M\\molarity =6.9\times 10^{-3}\ M\\[/tex]
Which of the following elements does not lose an electron easily? NA F MG AL
Answer:
F
EXPLANATION
Among the given elements fluorine(F)can not lose electrons easily because of its high electron affinity, high nuclear charge and high electronegativity.
Answer:
F
Explanation:
it won't lose electron , rather it would gain electron to complete its octate......
Electronic Configuration of F = 2,7
So F will gain 1 electron ....
What is the [tex]K_{c}[/tex] Expression for the following reaction [tex]C_{6}H_{12}O_{6} + O_{2} \ \ - \ \ \textgreater \ 6H_{2}O+6CO_{2}[/tex] NO ABSURD ANSWERS!
Answer:
[tex]\boxed{\mathrm{view \: explanation}}[/tex]
Explanation:
This is an irreversible reaction, we cannot derive any [tex]\mathrm{K_c}[/tex] expression for it. The [tex]\mathrm{K_c}[/tex] expression can only be derived for reversible reactions and not irreversible reactions. We cannot derive the [tex]\mathrm{K_c}[/tex] expression for this reaction.
How many significant figures are there in 6.07x10^-15?
Answer:
3
Explanation:
6.07 has 3 digits and all are significant
For a system, H2(g) + I2(g) ⇌ 2 HI(g), Kc = 62.9 at 750 K. 2.80 moles of HI were placed in a 10.0-liter container, brought up to 750 K, and allowed to come to equilibrium. Which situation described below is true, at equilibrium?
a. [HI] = 2 × [H2]
b. [HI] = [H2]
c. [HI] < [H2]
d. [HI] > [H2]
e. [H2] > [I2]
Answer:
d. [HI] > [H2]
Explanation:
The explanation at equilibrium is shown below:-
Data provided [tex]H_2(g) + I(g) \rightleftharpoons 2HI_(g)[/tex]
Initial concentration - - [tex]\frac{2.80}{10}[/tex] = 0.280 M
At equilibrium x x 0.280 - 2x
[tex]K_c = \frac{(HI)^2}{(H_2)(I_2)} = 62.9[/tex]
[tex]= \frac{(0.280 - 2x)^2}{x^2} = 62.9\\\\4x^2 - 1.12x + 0.0784 = 62.9x^2[/tex]
After solve the above equation we will get
x = 0.0282 M
Therefore at equilibrium
[tex][H_2] = [I_2] = x = 0.0282M\\\\[/tex]
[tex][HI] = 0.280 - 2x = 0.2236 M[/tex]
Hence, the correct option is d.
The temperature of a sample of liquid water changes from 50°C to 30°C. Which statement best explains the change
that must happen at the molecular level?
ОООО
The molecules move more quickly and their average kinetic energy increases.
The molecules move more slowly and their average kinetic energy decreases.
The molecules move more quickly and their average kinetic energy decreases.
The molecules move more slowly and their average kinetic energy increases.
Answer:
The molecules move more slowly and their average kinetic energy decreases
Explanation:
The increased temperature meant that the atoms in liquid had a greater average energy of motion so as the temperature decreases the reaction would be inverse.
The branch of science which deals with the chemicals bond is called chemistry.
The correct option is B.
The energy which is produced by the motion of the particles is called kinetic energy. Temperature increases the motion of the particles. So, the kinetic energy increases when the temperature rises.
According to the question, the temperature of the water decreases therefore the kinetic energy decreases.
Hence, the correct option is B that is the molecules move more slowly and their average kinetic energy decreases.
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You are a forensic scientist working on a murder case. You have taken the blood sample from the crime scene and put it through Electrophoresis and Southern blotting. What step do you need to take next? A. Add ethanol B. Add restriction enzymes C. Add minisatellites D. Add radioactive probes
Add minisatellites. Hence, option C is correct.
What is Electrophoresis?Electrophoresis is a laboratory technique used to separate DNA, RNA or protein molecules based on their size and electrical charge.
You are a forensic scientist working on a murder case. You have taken the blood sample from the crime scene and put it through Electrophoresis and Southern blotting. you need to add minisatellites.
Hence, option C is correct.
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For reaction: 2 C + O2 --> 2 CO2 If 5.50 g C was reacted with enough O2, what would be the volume (in liter) of the CO2 generated at STP? (0 C and 1 atm)
Answer:
10.2 L of CO₂
Explanation:
Our reaction is:
2C + O₂ → 2CO₂
We convert the mass of C, to moles:
5.50 g / 12g/mol = 0.458 moles
Ratio is 2:2, so if 2 moles of C can produce 2 moles of CO₂ then 0.458 moles of C would produce 0.458 moles of gas.
By the Ideal Gases Law, we know that 1 mol of gas is contained in 22.4L, so:
0.458 mol . 22.4L / 1mol = 10.2 L
How many atoms are in 10g of Al
Answer:
2.22 x 10²³
Explanation:
number of atoms = mole x 6 x 10²³first we have to find number of moles
moles = mass(g) / molar mass (Mr) (g/mol)mol = 10/27
mol= 0.37 mol
Now,
number of atoms = mole x 6 x 10²³
= 0.37 x 6 x 10²³
= 2.22 x 10²³
A container initially holds 5.67 x 10^10-2 mol of propane and has a volume of V1. The volume of the container was increased by adding an additional 2.95 x 10^-2 mol of propane to the container, so that the container has a final volume of 1.93 L. If the temperature and pressure are constant, what was the initial volume of the container ,V1?
Answer:
The initial volume of the container was 1.27L
Explanation:
Avogadro's law states that under the same pressure and temperature, equal moles of gases occupies equal volume. The equation is:
V₁n₂ = V₂n₁
Where V is volume and n moles of 1, initial state and 2, final state.
In the problem, initial moles are 5.67x10⁻², final moles after the addition are:
5.67x10⁻² + 2.95x10⁻² = 8.62x10⁻² moles
And, after the addition, the volume is 1.93L.
Replacing in Avogadro's law:
V₁×8.62x10⁻² moles = 1.93L×5.67x10⁻² moles
V₁ = 1.27L
The initial volume of the container was 1.27LTwo oxides of lead were separately reduced to metallic lead by heating in a current of
i) Mass of yellow oxide taken=3.45g
ii) Mass of brown oxide taken=1.227g
Loss in mass during reduction=16g
Show that the above data illustrate the law of multiple proportions.
Answer:
HeyA ❤
Let us consider the mass of oxygen as 1 g.
Mass of lead obtained from yellow oxide = 3.45 g – 0.24 g = 3.21 g
Mass of oxygen = 0.24 g
The mass of lead that combines with 0.24 g of oxygen = 3.21 g
Therefore, mass of lead that combines with 1 g of oxygen = 3.21/ 0.24 = 13.4 g
Mass of lead obtained from brown oxide = 1.227 g – 0.16 g = 1.067
Mass of oxygen = 0.16g
The mass of lead that combines with 0.16 g of oxygen = 1.067 g
Therefore, mass of lead that combines with 1 g of oxygen = 1.067/ 0.16 = 6.66 g
Now, ratio of masses of lead which combines with a fixed mass of oxygen = 13.4 : 6.66
= 2 :1
Thus, masses of lead which combine with the fixed mass of oxygen are in the ratio of (2:1) i.e. small whole numbers.
Hence, the law of multiple proportions is illustrated.
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Which event is most likely occurring? diffusion because particles move from regions of high concentration to regions of low concentration diffusion because particles move from regions of low concentration to regions of high concentration effusion because there is a movement of a gas through a small opening into a larger volume effusion because there is a movement of a gas through a large opening into a smaller volume
Answer: c
Explanation: effusion because there is a movement of a gas through a small opening into a larger volume
A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion. B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion. C. If Assertion is true statement but Reason is false. D. If Assertion is false and Reason is true Assertion: .Formation of soluble products from insoluble ones is called precipitation. Reason : Precipitation involves formation of insoluble products from soluble ones
Answer:
D- Assertion is false and Reason is true
Explanation:
Precipitation is said to have occurred when an insoluble product is formed from soluble ones. Let us take an instance;
BaCl2(aq) + H2SO4(aq) -------> BaSO4(s) + 2HCl(aq)
The barium sulphate so formed is an insoluble product obtained from the reaction of soluble barium chloride and sulphuric acid. This is a typical example of a double replacement reaction as the both ions exchanged partners.
Thus, the assertion is false but the reason is true.
Based on my previous question I have posted.. Answer this.. It's the continuation
Table 7.3 is different
Answer:
We don't know what solvent X and solvent Y are, but from the chart, we can see that in solvent X, hydrochloric acid can conduct electricity (bulb lights up), and react with calcium carbonate.
So, we can say the electrical conductivity when HCl is dissolved in solvent X is high, and when HCl is dissolved in solvent Y, the electrical conductivity is low (because light bulb doesn't light up).
Additionally, in solvent X, HCl ionizes, this shows the property of acids: reacts with carbonates to give CO2 (because CO2 reacts with lime water to make it cloudy).
In solvent Y, HCl does not ionize, so there is no reaction between acid and calcium carbonate.
Select the correct answer.
What is the reason for heat transfer from one substance to another
Answer:
Difference in temperature.
Explanation:
Conduction is the movement of heat energy through a substance or from one substance to another by direct contact of atoms and molecules. Heat moves directly from one molecule to another. The heat energy speeds up the movement of the atoms and they collide with other molecules setting them into faster motion.
Si el elemento "X" tiene 8 protones y el elemento "Y" tiene 11 protones, al reaccionar ¿Qué tipo de enlace pueden formar? Seleccione una: a. Metálico. b. Covalente puro. c. Covalente polar. d. Iónico.
Answer:
D; Iónico
Explanation:
El elemento con 8 protones es oxígeno, mientras que el elemento con 11 protones es sodio.
El sodio es un metal alcalinotérreo, mientras que el oxígeno no es un metal.
En general, cuando tenemos un elemento metálico como el sodio, que se une con uno no metálico como el oxígeno, el tipo de enlace formado como resultado de la transferencia completa de electrones desde la capa de valencia del sodio a la capa de valencia del oxígeno para completar su propia configuración de octeto se denomina enlace electrovalente o, más generalmente, enlace iónico
Why are the oxidation and reduction half-reactions separated in an
electrochemical cell?
Answer:
Electrochemical cells typically consist of two half-cells. The half-cells separate the oxidation half-reaction from the reduction half-reaction and make it possible for current to flow through an external wire.
Explanation:
what is the smallest particle which prossesses the properties of a compound called?
Answer:
Molecule
Explanation:
Compounds are chemical substances comprising of two or more elements. The smallest particle contained in a compound is the MOLECULE. Molecules are combinations of atoms (same or different) of an element held together by a chemical bond.
Since a compound is a molecule with two or more elements combined, the chemistry of the molecules contained in a compound determines its chemical properties. This means that the molecules of a compound are responsible for the interactions of a compound in a chemical reaction. Examples of molecules are H2O, N2, O3 etc.
Matter is composed of exceedingly small particles called atoms. An atom is the
smallest unit of an element that can participate in a -------
Answer:
Matter is composed of exceedingly small particles called atoms. An atom is the
smallest unit of an element that can participate in a chemical reaction.
Answer:
Chemical reaction.
Explanation:
The reaction between hydrogen gas and chlorine gas produces hydrogen chloride according to the following equation: H2(g) + Cl2(g) → 2HCl(g). Using the following bond enthalpies(D) calculate the enthalpy of reaction. D(H-H) =436 kJ/mol; D(Cl-Cl) = 243 kJ/mol D(H-Cl) = 432 kJ/mol
Answer:
The enthalpy of reaction is -185 kJ
Explanation:
To get the reaction:
H₂(g) + Cl₂(g) → 2 HCl(g)
you must follow the following steps:
1) Reactive molecules must break their bonds to obtain their atoms.
H₂(g) → 2 H(g)
Cl₂(g) → 2 Cl(g)
Bond energy (or enthalpy) is the energy required to break one mole of bonds of a gaseous substance. In the case of diatomic molecules with a single bond, it corresponds to the energy necessary to dissociate 1 mole of said substance in the atoms that form it.
Whenever you want to break links you must supply energy, so the link enthalpy will have positive values; while when a mole of bonds is formed energy is released and the bond enthalpy of this process will be negative.
In this case you will then have:
H₂(g) → 2 H(g) ΔH=436 kJ/mol
Cl₂(g) → 2 Cl(g) ΔH=243 kJ/mol
So the total energy needed to break all the bonds is:
ΔH=1 mol*436 kJ/mol +1 mol* 243 kJ/mol= 679 kJ
2) The atoms that were obtained in the break of the bonds must be combined to obtain the product.
2 H (g) + 2 Cl (g) → 2 HCl (g)
Being the single bond energy for one mole of 431 kJ H-Cl bonds and considering that two moles of H-Cl bonds are formed, the ΔH is:
ΔH = -2 moles* (432 kJ/mol) = -864 kJ
As mentioned, when a mole of bonds is formed energy is released, the bond enthalpy of this process will be negative. So the formation of HCl is negative.
Hess's law states that the energy change in an overall chemical reaction is equal to the sum of the energy changes in the individual reactions comprising it. So:
ΔHtotal= -864 kJ + 679 kJ
ΔHtotal= -185 kJ
The enthalpy of reaction is -185 kJ
unknown substance is heated from 10 celsius to 25 celsius, what happens at 17 Celsius
At 17 celsius ❤️
it will start to boil ❤️
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what is the relationship between ph and poh?
Answer:
pH and pOH denote the negative log of the concentration of hydrogen or hydroxide ions. High pH means that a solution is basic while high pOH means that a solution is acidic. ... So here the basic definition of pH is that it's equal to negative log base 10 of the concentration of protons in your solution.
pH and pOH are inversely proportional to one another i.e. as one increases, the other decreases and vice versa.
What is pH and pOH?pH and pOH are terms used to measure the level of acidity or alkalinity of a substance.
A basic solution has a pOH less than 7, while an acidic solution has a pOH greater than 7.
On the other hand, a basic solution has a pH greater than 7 while an acidic solution has a pH lesser than 7.
Therefore, it can be said that pH and pOH are related inversely i.e. as one decreases, the other increases.
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someone plz plz answer this hurry plz it
Answer:
b
Explanation:
Q1. Because metals are malleable, we use some of them to make saucepans. Give two other examples of uses of metals that depend on: (a):their malleability. (b):their ductility. (c):their ability to conduct electricity. [3]
Explanation:
(a):their malleability:
>iron making. iron worker heat the meat and hammer it to give them the desired shape.
> in the jewelry making process, like the gold or silver you wear are results due to the malleability of metal
(b):their ductility:
>for the making of high tension cable that connects different cities for transferring of electricity.
>for making wire gauze
(c):their ability to conduct electricity:
>for lighting up your house with light bulbs
>for using cooking stoves
>to make refrigerator work.
Answer:
a)gold and silver-used to make jewellery
b)gold and copper(we draw them in wires easily because they are not brittle)
c)copper and iron(this is because both of them are metal and metaps are best conductors of electricity)
Explanation:
uses of copper- to make utensils
to make wires for circuits
uses of silver-to make jewellery
to make mirrors
malleability is the property of a meta in which the metal can be changed into different shapes.
Ductility-can be drawn into thin wires.
A 25.0 mL sample of a solution of an unknown compound is titrated with a 0.115 M NaOH solution. The titration curve above was obtained with pH at equivalence point of around 8. The unknown compound is ________.
Answer:
Weak acid
Explanation:
A titration curve is a graphical description of the change in pH of the solution in the conical flask as the reagent is added from the burette. A titration curve can be plotted for the different kinds of acid and base titrations. The volume of the titrant is always plotted as the independent variable and the pH of the solution as the dependent variable. The equivalence point is read off from the titration curve. A titration curve is very important because it shows the pH at various points during the titration.
A weak acid/strong base titration leads to an equivalence point above 7. From the question, we were told that the pH at equivalence point lies around 8. Hence the unknown substance must be a weak acid.