North America and south africa
A substance which is made up of the same kind
of atom is known as?
Answer:
Element
Element : A pure substance composed of the same type of atom throughout. Compound : A substance made of two or more elements that are chemically combined in fixed amounts.
Explanation:
What are the effects of global warming?
the effects are: temperature rises, water shortages, and increased fire threats
một chất hữu cơ có cấu tạo c2h2 cho khí br2 vào ta được hỗn hợp khí
Answer:
C2H2 + Br2 → C2H2Br2
Explanation:
Copper wire has a high electrical conductivity.
True
False
Answer:
True
Explanation:
Copper has the highest electrical conductivity rating of all non-precious metals: the electrical resistivity of copper = 16.78 nΩ•m at 20 °C. Specially-pure Oxygen-Free Electronic (OFE) copper is about 1% more conductive (i.e., achieves a minimum of 101% IACS).
True is the correct answer.
Consider a hypothetical metal that has a density of 10.6 g/cm3, an atomic weight of 176.8 g/mol, and an atomic radius of 0.130 nm. Compute the atomic packing factor if the unit cell has tetragonal symmetry, values for the a and c lattice parameters are 0.570 and 0.341, respectively.
Answer:
0.3323
Explanation:
GIven that:
Density of the metal = 10.6 g/cm^3
atomic weight = 176.8 g/mol
atmic radius = 0.130 nm
values of a and c = 0.570 nm and 0.341 nm respectively
For us to determine the atomic packing factor, we need to first determine the volume of all spheres (Vs) and the volume of unit cell (Vc).
However, the number of atoms in the unit cell (n) can be computed as:
[tex]n = \dfrac{\rho * V_c *N_A}{A} \\ \\ n = \dfrac{(10.6) * (5.7)^2 (3.41)*(10^{-24}) *(6.022*10^{23})}{176.8}[/tex]
n = 4.0
Thus, the number of atoms in the unit cell is 4
∴
The atomic paking factor (APF) is calculated by using the formula:
[tex]\dfrac{Vs}{Vc} = \dfrac{4 * \dfrac{4}{3}\pi *R^3 }{a^2 *c} \\ \\ \\ \dfrac{Vs}{Vc} = \dfrac{4 * \dfrac{4}{3}\pi *(1.30*10^{-8})^3 }{(5.70*10^{-8})^2 *(3.41*10^{-8})}[/tex]
= 0.3323
The "Nutrition Facts" on a label of a 16 fluid ounce container of apple juice states that a serving size is 8 fluid ounces contains 176 Calories and 240 milligrams of potassium.
Nutrition Facts
Serving Size 8 fl. oz. (240mL)
Servings Per Container: 2
Amount Per Serving
Calories 176
% Daily Value*
Total Fat 0g 0 %
Sodium 32mg 1 %
Potassium 240mg 6 %
Total Carbohydrate 29g 10 %
Sugars 26g
Protein 0g
a) How many calories would 1 fluid ounce of apple juice contain?
b) How many milligrams of potassium would 1 fluid ounce of apple juice contain?
Answer:
a) 22 calories
b) 30 mg
Explanation:
Divide number of cal or mg of pot by 8 fl oz.
Consider the molecule PF5.
Indicate how many lone pairs you would find on the central atom:
Indicate how many total bonds are connected to the central atom (count single bonds as 1 bond, double bonds as 2 bonds, and triple bonds as 3 bonds):
Explanation:
here's the answer to your question
The standard entropy change of a reaction has a positive value. This reaction results in: Select the correct answer below: a decrease in entropy. an increase in entropy. no entropy change. neither an entropy increase nor decrease.
Explanation:
The standard entropy change of a reaction has a positive value. This reaction results in an increase in entropy.
Positive entropy means the system has increased its degree of disorderness.
The density of a gas cannot be measured.
True
False
Answer:
False
Explanation:
Answer:
False
Explanation:
In nature, one common strategy to make thermodynamically unfavorable reactions proceed is to couple them chemically to reactions that are thermodynamically favorable. As long as the overall reaction is thermodynamically favorable, even the unfavorable reaction will proceed.
Part A
Consider these hypothetical chemical reactions:
A⇌B,ΔG= 14.8 kJ/mol
B⇌C,ΔG= -29.7 kJ/mol
C⇌D,ΔG= 8.10 kJ/mol
What is the free energy, ΔG, for the overall reaction, A⇌D?
Part B
Firefly luciferase is the enzyme that allows fireflies to illuminate their abdomens. Because this light generation is an ATP-requiring reaction, firefly luciferase can be used to test for the presence of ATP. In this way, luciferase can test for the presence of life. The coupled reactions are
luciferin+O2ATP⇌⇌oxyluciferin+lightAMP+PPi
If the overall ΔG of the coupled reaction is -7.50 kJ/mol , what is the equilibrium constant, K, of the first reactions at 11 ∘C ? The ΔG for the hydrolysis of ATP to AMP is −31.6 kJ/mol.
Answer:
[tex]\triangle G= -6.7 KJ/mol[/tex]
Explanation:
From the question we are told that:
Chemical Reactions:
X=A⇌B,ΔG= 14.8 kJ/mol
Y=B⇌C,ΔG= -29.7 kJ/mol
Z=C⇌D,ΔG= 8.10 kJ/mol
Since
Hess Law
The law states that the total enthalpy change during the complete course of a chemical reaction is independent of the number of steps taken.
Therefore
Generally the equation for the Reaction is mathematically given by
[tex]T = +1 * X +1 * Y +1 *Z[/tex]
Therefore the free energy, ΔG is
[tex]\triangle G=1 * \triangle G*X +1 * \triangle G*Y +1 * \triangle G *Z[/tex]
[tex]\triangle G= +1 * (14.9) +1 * (-29.7) +1 * (8.10)[/tex]
[tex]\triangle G= -6.7 KJ/mol[/tex]
What mass of precipitate (in g) is formed when 250.0 mL of 0.150 M CuCl₂ is mixed with excess KOH in the following chemical reaction?
CuCl₂(aq) + 2 KOH(aq) → Cu(OH)₂(s) + 2 KCl(aq)
Answer:
3.6487g
CuCl2 moles reacted = (0.15×250)/1000
according to balanced chemical equation
precipitated Cu(OH)2 moles = Reacted CuCl2 moles
molar mass of Cu(OH)2 = 63.5+ (17+1)×2 = 97.5
mass of precipitate = (97.5 × 0.15×250)/1000
= 3.648g
The functional groups in an organic compound can frequently be deduced from its infrared absorption spectrum.
a. True
b. False
Answer:
a. True
Explanation:
The main information that gives an infrared absorption spectrum is the type of functional groups that are present in an organic compound. The infrared (IR) spectroscopy is based on the fact that functional groups absorb light in the IR region of the electromagnetic spectrum (approximately at 2,500-16,000 nm) and induces a vibrational excitation of the covalently bonded atoms in the group. The vibration of the atoms can be of different types, such as stretching, bending, etc. Each functional group (such as the carbonyl group) in an organic compound absorbs at a specific IR frequency so they can be distinguished from an IR spectrum.
Hydrogen chloride decomposes to form hydrogen and chlorine, like this:
2HCl(g) + H2(g) â Cl2(g)
Also, a chemist finds that at a certain temperature the equilibrium mixture of hydrogen chloride, hydrogen, and chlorine has the following composition:
compound pressure at equilibrium
HCl 84.4 atm
H2 77.9 atm
Cl2 54.4
Required:
Calculate the value of the equilibrium constant for this reaction. Round your answer to significant digits.
Solution :
Given :
Partial pressure of HCl, [tex]$P_{HCl}$[/tex] = 84.4 atm
Partial pressure of [tex]H_2[/tex], [tex]$P_{H_2}$[/tex] = 77.9 atm
Partial pressure of [tex]Cl_2[/tex], [tex]$P_{Cl_2}$[/tex] = 54.4 atm
Reaction :
[tex]$2HCl (g) \leftrightharpoons H_2(g) + Cl_2(g)$[/tex]
Using equilibrium concept,
[tex]$k_p=\frac{(P_{H_2})(P_{Cl_{2}})}{(P_{HCl})^2}$[/tex]
[tex]$k_p=\frac{77.9 \times 54.4}{(84.4)^2}$[/tex]
[tex]$k_p=0.594$[/tex]
[tex]k_p=0.59[/tex] (in 2 significant figures)
or [tex]k_p=5.9 \times 10^{-1}[/tex]
Determine whether the statement about identifying a halide is true: Regardless of any concentration of ammonium solution, the precipitates in the reaction solution of my unknown halide after 0.1M AgNO3 remain because my unknown halide solution contains Br. Select one: True False
Answer:
False
Explanation:
The statement ; Regardless of any concentration of ammonium solution the precipitate of unknown halide after 0.1M AgNO3 will remain is FALSE
This is Because the remaining concentration of AgNO3 is dependent on the solubility of Ag⁺
“Enter the conjugate acids of no2- and no3-“
Answer:
nitrit,nitrat
You have been contracted to determine how different salts affect the pH of water. Which of the solids in the following set should you test to investigate for the effects of cations on pH?
a. AlBr3
b. Rb2SO3
c. MgCl2
d. RbBrO
e. CH3NH3Br
Answer:
Hence the solids that should test to investigate the effects of cations on pH is
[tex]AlBr_{3}[/tex] (Cation is Al 3+)
[tex]MgCl_{2}[/tex] ( Cation is Mg 2+)
[tex]CH_{3} NH_{3} Br[/tex] ( Cation is NH2+).
Explanation:
The solids in the following should you test to investigate the effects of cations on pH.
[tex]AlBr_{3}[/tex] contains (Cation is Al 3+)
[tex]MgCl_{2}[/tex] contains ( Cation is Mg 2+)
[tex]CH_{3} NH_{3} Br[/tex] contains( Cation is NH2+ )
The atoms or the molecules containing the positive charge that gets attracted to the cathode are called cations. The compounds a. [tex]\rm AlBr_{3}[/tex], c. [tex]\rm MgCl_{2}[/tex] and e. [tex]\rm CH_{3}NH_{3}Br[/tex] should be investigated.
What are cations and pH?Cations are the positive charge containing molecules and atoms that have more protons in their nucleus than the number of electrons in their shells. They are formed when they lose one or more electrons to another atom.
The addition or release of the electrons of the cations and anions affects the pH system as absorption of the cation decreases the pH and absorption of the anions increases the pH.
Hence, [tex]\rm Al^{3+}[/tex], [tex]\rm Mg^{2+}[/tex] and [tex]\rm NH^{2+}[/tex] are the cation that should be investigated. The addition of the cations will reduce the pH of the reaction.
Therefore, absorption of the cation reduces the pH.
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how many moles of CO2 are formed from 3.0 mol of C2H2
Answer:
50.0 moles C02
Explanation:
First write down the CORRECTLY balanced equation. NOTE: The equation you provide is incorrect.
2C2H2(g) + 5O2(g) ==> 4CO2(g) + 2H2O(g) CORRECT EQUATION
Next, look at the stoichiometric ratio of C2H2 to CO2. You can see it is 2 moles C2H2 produces 4 moles CO2.
Thus, 25.0 moles C2H2 x 4 moles CO2/2 moles C2H4 = 50.0 moles CO2
Gaseous methane (CH4) will react with gaseous oxygen (O2) to produce gaseous carbon dioxide (CO2) and gaseous water . Suppose 2.73 g of methane is mixed with 6.7 g of oxygen. Calculate the maximum mass of water that could be produced by the chemical reaction. Round your answer to significant digits.
Answer:
3.8g of H2O are produced
Explanation:
The balanced reaction of the problem is:
CH4 + 2O2 → CO2 + 2H2O
Where 1 mole of CH4 reacts with 2 moles of O2
To solve this question we need to find, as first, the moles of each reactant in order to find limiting reactant. With limiting reactant we can find the moles of H2O produced and its mass as follows:
Moles CH4 - 16.04g/mol-
2.73g * (1mol/16.04g) = 0.170 moles CH4
Moles O2 -32g/mol-
6.7g (1mol/32g) = 0.209 moles O2
For a complete reaction of 0.170 moles of CH4 are needed:
0.170 moles CH4 * (2 mol O2 / 1mol CH4) = 0.340 moles O2
As there are just 0.209 moles of O2, oxygen is limiting reactant
The moles of water produced are:
0.209 moles O2 * (2mol H2O / 2mol O2) = 0.209 moles H2O
Mass water -Molar mass: 18.01g/mol-
0.209 moles H2O * (18.01g/mol) = 3.8g of H2O are produced
Three peptides were obtained from a trypsin digestion of two different polypeptides. Indicate the possible sequences from the given data.
a. Val-Gly-Arg
b. Ala-Val-Lys
c. Ala-Gly-Phe
Answer:
A) Val-Gly-Arg-Ala-Val-Lys-Ala-Gly-Phe
B) Ala-Val-Lys-Val-Gly-Arg-Ala-Gly-Phe
Explanation:
The possible sequences that could be obtained from the available dat provided are :
A) Val-Gly-Arg-Ala-Val-Lys-Ala-Gly-Phe
B) Ala-Val-Lys-Val-Gly-Arg-Ala-Gly-Phe
Trypsin is generally a catalyst for the breakdown of proteins into smaller peptides ( during the hydrolysis of peptide bonds )
What volume of a 1.5 M KOH solution is needed to provide 3.0 moles of KOH?
3.0 L
2.0 L
4.5 L
0.50 L
0.22 L
Please explain!
Explanation:
here's the answer to your question
2.0 L
Answer:
Solution given:
no. of mole(n)=3.0mole
molarity(M)=1.5M
we have
Volume of a substance is equal to the ratio of its no of mole to its molarity.
By this we get a relation:
Volume=no.of mole/molarity
substituting value
Volume=3.0/1.5=2
The required volume is 2 litre.
What type of oxide is each of the following? NO2, CO, Fe2O3, Al2O3, P20,
Nitrogen Dioxide
Carbon Monoxide
Iron (II) Oxide
Aluminum Oxide
DiPhosphorus Monoxide
All of the following are characteristics of metals except: Group of answer choices good conductors of heat malleable ductile often lustrous tend to gain electrons in chemical reactions
Answer:
Hence the correct option is the last option that is tends to gain electrons in chemical reactions to become anions.
Explanation:
Metals tend to donate electrons in chemical reactions to become cations.
A student dissolves 12.6g of amonium nitrate(NH4NO3) in 250.g of water in a well-insulated open cup. She then observed the temperature of the water fall from 23.0°C to 18°C over the course of 6.1 minutes.
NH4NO3 â NH4+ (aq) + NO3^-(aq)
a. Is this reaction exothermic, endothermic, or neither?
b. If you said the reaction was exothermic or calculate the amount of heat that was released or absorbed by the reaction in this case.
c. Calculate the reaction enthalpy ÎHrxn per mole of NH4NO3.
Answer:
a. Endothermic.
b. [tex]Q_{rxn}=5493.6J[/tex]
c. [tex]\Delta H_{rxn}=35.0kJ/mol[/tex]
Explanation:
Hello there!
In this case, according to the given information for this calorimetry problem, it turns out possible for us to proceed as follows:
a. Due to the fact that the temperature of water goes from 23.0 °C to 18.0 °C, we infer this reaction is endothermic as the ammonium nitrate absorbed heat from the water.
b. Here, we consider the following heat equation:
[tex]Q_{rxn}=-Q_{water}[/tex]
Whereas we solve for the heat of reaction by means of the mass of the solution (both water and ammonium nitrate), the specific heat of the solution (we assume it is equal to that of water) and the temperature change:
[tex]Q_{rxn}=-m_{solution}C_{solution}(T_f-T_i)\\\\Q_{rxn}=-(12.6g+250.g)(4.184\frac{J}{g\°C} )(18.0\°C-23.0\°C)\\\\Q_{rxn}=5493.6J[/tex]
c. Here, we divide the previously calculated heat by the moles of ammonium nitrate (molar mass = 80.043 g/mol) to obtain the enthalpy of reaction per mole of this compound:
[tex]n_{NH_4NO_3}=12.6g*\frac{1mol}{80.043 g}=0.157mol\\\\\Delta H_{rxn}=\frac{5493.6J}{0.157mol} =34898.7J/mol\\\\\Delta H_{rxn}=35.0kJ/mol[/tex]
Regards!
You need to make an aqueous solution of 0.121 M magnesium acetate for an experiment in lab, using a 250 mL volumetric flask. How much solid magnesium acetate should you add
Answer:
4.27 g
Explanation:
Number of moles = concentration × volume
Concentration = 0.121 M
Volume = 250 mL
Number of moles = 0.121 M × 250/1000 L
Number of moles = 0.03 moles
Number of moles = mass/molar mass
Mass= Number of moles × molar mass
Mass= 0.03 moles × 142.394 g/mol
Mass = 4.27 g
Which redox reaction would most likely occur if silver and copper metal were added to a solution that contained silver and copper ions?
A. Cu + Agt Cu2+ + 2Ag
B. Cu2+ + 2Ag* → Cu + 2Ag
C. Cu2+ + 2Ag → Cu + 2Ag+
D. Cu + 2Ag Cu²+ + 2Ag+
give the wrong answer and I'm reporting
Answer:
B
Explanation:
b/c copper is readuction agent
The most likely redox reaction that would occur if silver and copper metal were added to a solution that contained silver and copper ions is [tex]\rm Cu^{2+} + 2Ag \rightarrow Cu + 2Ag^+[/tex]. The correct answer is option C.
Redox reaction is a reaction in which reduction and oxidation takes place simultaneously.
In this reaction:
[tex]\rm Cu^{2+} + 2Ag \rightarrow Cu + 2Ag^+[/tex]
Copper metal has a higher reduction potential than silver metal, which means that it will be oxidized to [tex]\rm Cu^{2+}[/tex] ions before silver metal is oxidized to [tex]\rm Ag^+[/tex] ions.
The [tex]\rm Cu^{2+}[/tex] ions in the solution will then react with the silver metal to form [tex]\rm Ag^+[/tex] ions and Copper metal. This reaction is an example of a displacement reaction, where a more reactive metal removes a less reactive metal from its compound.
Therefore, option C. [tex]\rm Cu^{2+} + 2Ag \rightarrow Cu + 2Ag^+[/tex] is the correct answer.
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A functional group introduces heteroatoms into a carbon chain to increase
polarity.
chain length.
molecular mass.
reactivity.
Answer:
reactivaty
Explanation:
here you go for the answer
Nitrous oxide, NO, decomposes exothermically into nitrogen gas and oxygen gas. When graphing [NO] versus time, a straight line can be drawn through the experimental points. From this information, determine the reaction order.
Answer:
Zero-Order
Explanation:
The exothermic decaying of nitrous oxide at 575° C will lead to [tex]N_{2} and O_{2}[/tex] as follows:
[tex]2N_{2}O[/tex] → [tex]2N_{2}(g) + O_{2} (g)[/tex]
Hot platinum wire in the above reaction would function as a catalyst in the zero-order. However, if the reaction is considered in the gaseous phase, it will be more inclined towards second-order.
In the given scenario([tex]2N_{2}O[/tex] → [tex]2N_{2}(g) + O_{2} (g)[/tex]), the reactant molecules of Nitrous oxide are restricted to the ones which have linked themselves to the catalyst's surface. Once this limited surface is filled, the extra molecules of gas would remain vacant until the previously attached molecules with the surface are decayed entirely.
A reaction vessel is charged with phosphorus pentachloride, which partially decomposes to phosphorus trichloride and molecular chlorine according to the following reaction:
PCl5(g)â PCl3(g)+Cl2(g)
When the system comes to equilibrium at 250.0°C, the equilibrium partial pressures are: PPCl5 = 0.688 atm and PPCl3 = PCl2 = 0.870 atm.
Required:
What is the value of Kp at this temperature?
Answer:
Kp = 1.10.
Explanation:
Hello there!
In this case, according to the given information about the chemical reaction at equilibrium, it turns out possible for us to find the partial pressures-based equilibrium expression for the decomposition of phosphorous pentachloride by applying the law of mass action whereas the pressure of products is divided by that of the reactants as shown below:
[tex]Kp=\frac{p_{PCl_3}p_{Cl_2}}{p_{PCl_5}}[/tex]
Now, we plug in the given pressures to obtain:
[tex]Kp=\frac{0.870}{0.688} \\\\Kp=1.10[/tex]
Regards!
What is molarity?
A. A measure of saturation.
B. A ratio of moles of solvent to moles of solution.
C. A measure of moles.
D. A measure of concentration.
Answer:
Molarity is a measure of concentration
I Hope its right if not so advance sorry :)
The molarity measures the number of moles of the solute present per liter of the solution and it measures the concentration of the solution. option D is correct.
What is molarity?Molarity is the amount or the number of moles present in per liter of the solution it is the unit to measure the concentration of the moles.
Unit of molarity will be moles per liter and the temperature does not affect the molarity of the solution. molarity can be calculated by dividing the concentration of the solution by the molar mass of the given element.
molarity = weight / mass × 1000/ volume in liters.
With the help of this formula, we can calculate the molarity.
Therefore, molarity measures the number of moles of the solute present per liter of the solution and it measures the concentration of the solution. option D is correct.
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what is the difference between red phosphorus and white phosphorus?
Answer:
White phosphorusRed PhosphorusIt is insoluble in water but soluble in carbon disulphide.It is insoluble in both water and carbon disulphide.It undergoes spontaneous combustion in air.It is relatively
Explanation:
I hope it will help you
