Place the gelatin powder in a chilled container and pour lukewarm water over it
Answer:
2
Explanation:
I think because the hot water would enable it to dissolve much faster as compared to cold water.its like when adding sugar to a cup of tea it would dissolve much faster in hot tea rather than cold tea
What is the balanced form of the following equation?
Br2 + S2O32- + H2O → Br1- + SO42- + H+
Answer:
5 Br₂ + S₂O₃²⁻ + 5 H₂O ⇒ 10 Br⁻ + 2 SO₄²⁻ + 10 H⁺
Explanation:
We will balance the redox reaction through the ion-electron method.
Step 1: Identify both half-reactions
Reduction: Br₂ ⇒ Br⁻
Oxidation: S₂O₃²⁻ ⇒ SO₄²⁻
Step 2: Perform the mass balance, adding H⁺ and H₂O where appropriate
Br₂ ⇒ 2 Br⁻
5 H₂O + S₂O₃²⁻ ⇒ 2 SO₄²⁻ + 10 H⁺
Step 3: Perform the charge balance, adding electrons where appropriate
2 e⁻ + Br₂ ⇒ 2 Br⁻
5 H₂O + S₂O₃²⁻ ⇒ 2 SO₄²⁻ + 10 H⁺ + 10 e⁻
Step 4: Make the number of electrons gained and lost equal
5 × (2 e⁻ + Br₂ ⇒ 2 Br⁻)
1 × (5 H₂O + S₂O₃²⁻ ⇒ 2 SO₄²⁻ + 10 H⁺ + 10 e⁻)
Step 5: Add both half-reactions
5 Br₂ + S₂O₃²⁻ + 5 H₂O ⇒ 10 Br⁻ + 2 SO₄²⁻ + 10 H⁺
385 x 42.13 x 0.079 is (consider significant figures):
385 x 42.13 x 0.079 = 1281.38395
The half life of radium-226 is 1600 years. If you have 200 grams of radium today how many grams would be present in 8000 years?
Answer:
Half life is the time taken by a radio active isotope to reduce by half of its original amount. Radium-226 has a half life of 1602 years meaning that it would take 1602 years for a mass of radium to reduce by half.
Number of half lives in 9612 years = 9612/1602 = 6 half lives
New mass = Original mass x (1/2)n where n is the number of half lives.
Therefore, New mass= 500 x (1/2)∧6
= 500 x 0.015625
= 7.8125 g
Hence the mass of radium after 9612 years will be 7.8125 grams.
Explanation:
Answer:
[tex]\boxed {\boxed {\sf 6.25 \ grams}}[/tex]
Explanation:
We are asked to find the mass of a sample of radium-226 after half-life decay. We will use the following formula:
[tex]A= A_o *\frac{1}{2}^{\frac{t}{h}}[/tex]
In this formula, [tex]A_o[/tex] is the initial amount, t is the time, and h is the half-life.
For this problem, the initial amount is 200 grams of radium-226, the time is 8,000 years, and the half-life is 1,600 years.
[tex]\bullet \ A_o= 200 \ g \\\\bullet \ t= 8,000 \ \\\bullet \ h= 1,600[/tex]
Substitute the values into the formula.
[tex]A= 200 \ g * \frac{1}{2} ^{\frac{8.000}{1,600}[/tex]
Solve the fraction in the exponent.
[tex]A= 200 \ g * \frac{1}{2}^{5}[/tex]
Solve the exponent.
[tex]A= 200 \ g *0.03125[/tex]
[tex]A= 6.25 \ g[/tex]
In addition, we can solve this another way. First, we find the number of half-lives by dividing the total time by the half-life.
8,000/1,600= 5 half-livesEvery half-life, 1/2 of the mass decays. Divide the initial mass in half, then that result in half, and so on 5 times.
1. 200 g/2= 100 g2. 100 g / 2 = 50 g3. 50 g / 2 = 25 g 4. 25 g / 2 = 12.5 g5. 12.5 g / 6.25 gAfter 8,000 years, 6.25 grams of radium-226 remains.
11. An isotope Q has 18 neutrons a mass number of 34. (a) (i) What is an isotope? An isotope is one of two or C (b) Write its electron arrangement. Mass number=34 Number of neutrons=18 Number of Protons = 34-15-16 (c) To which period and group does Q belong? Protors - Electons - Atomic number Period - Group (d) How does Q form its ion?
An isotope is an element with the same atomic number but different mass number due to differences in number of neutrons.
electron configuration is 2,8,6.
Belongs to group 6 and period group 3.
It forms an ion by accepting 2 electrons
A graph of gas pressure versus the number of particles in a container is a straight line. Which other relationship will have a similar graph?
Answer:
volume versus temperature, because they are also directly proportional.
Explanation:
Just took the test!
Please help fast
All four referenced Greek thinkers: Democritus, Aristotle, Archimedes, and Anaxagoras, observed Nature and argued for his theory of
the composition of matter and natural laws. Only one of them tested his hypothesis and proposed a natural laws based on reproducible
observations, controlled experiments, and mathematical reasoning. All others used logic and thought experiments, as philosophers do,
to support their theories. Who is the experimental scientist in this group?
O Democritus
O Aristotle
O Archimedes
O Anaxagoras
Answer:
Anaxagoras was perhaps the first literate person to attempt to explain physical phenomena rationally, basing his ideas upon careful observations and simple experiments. This is fundamental to modern science and is the sine qua non of environmental study.
Based on the standard EMF series and your knowledge of half-reactions, determine the cell potential and spontanei ty of a cell that consists of a pure cobalt electrode in a solution of Co^2+ ions; the other half is a lead electrode immersed in a Pb^2+ solution.
Pb +2e- Pb Sn +2e Sn Ni 2e Ni Co 2e -0.126 -0.136 -0.250 -0.277 Co
a. +0.403, spontaneous
b. -0.403, nonspontaneous
c. +0.151, spontaneous
d. -0.151, nonspontaneous
Answer:
+0.151, spontaneous
Explanation:
Given that;
Co^2+(aq) + 2e ---->Co(s) -0.28 V
Pb^2+(aq) + 2e ---->Pb(s). -0.13 V
Hence Co is the anode and Pb is the cathode
E°cell = E°cathode - E°anode
So;
E°cell = -0.13 V - (-0.28 V)
E°cell = 0.15 V
The cell reaction is spontaneous since E°cell is positive.
What Volume of silver metal will weigh exactly 2500.0g. The density of silver
Answer:
cm3 = 2500.0 g / 10.5 g/cm3 = 238 cm3
Write a balanced chemical equation for the reaction that occurs
when:
(a) titanium metal reacts with O21g2;
(b) silver(I) oxide decomposes into silver metal and oxygen gas when heated;
(c) propanol, C3H7OH1l2 burns in air;
(d) methyl tert-butyl ether, C5H12O1l2, burns in air.
Answer:
Explanation:
A balanced chemical equation refers to the reaction taking place whereby the number of atoms associated in the reactants side is equivalent to the number of atoms on the products side.
From the given information, the balanced equations are as follows:
[tex]\mathbf{(a) \ \ \ Ti(s) + O_{2(g)} \to TiO_{2(s)}}[/tex]
[tex]\mathbf{(b) \ \ \ 2Ag_{2}O \to 4Ag_{(s)} + O_{2(g)}}[/tex]
[tex]\mathbf{(c) \ \ \ 2C_3H_7OH + 9O_2 \to 6CO_2+8H_2O}[/tex]
[tex]\mathbf{(d) \ \ \ 2C_5 H_{12}O \to 10 CO_2 + 12 H_2O}[/tex]
What volume of each solution contains 0.14 mol of KCl? Express your answer using two significant figures.
1.8 M KCl
Answer:
Solution given:
1 mole of KCl[tex]\rightarrow [/tex]22.4l
1 mole of KCl[tex]\rightarrow [/tex]74.55g
we have
0.14 mole of KCl[tex]\rightarrow [/tex]74.55*0.14=10.347g
74.55g of KCl[tex]\rightarrow [/tex]22.4l
10.347 g of KCl[tex]\rightarrow [/tex]22.4/74.55*10.347=3.11litre
volume of each solution contains 0.14 mol of KCl contain 3.11litre.
[tex]\:[/tex]
1 mole of KCl → 22.4l
1 mole of KCl → 74.55g
we have
0.14 mole of KCl → 74.55*0.14=10.347g
74.55g of KCl → 22.4l
10.347 g of KCl → 22.4/74.55*10.347=3.11litre
volume of each solution contains 0.14 mol of KCl contain 3.11litre.
What is the basic unit of chemistry?
O A. The bond
O B. The atom
O C. The sun
O D. The cell
Answer:
B. The atom
Explanation:
Cells are the most basic unit of structure and the smallest unit of matter is the atom.
Answer:
B. The atom
Explanation:
yeee it was right
The density of toluene (C7H8) is 0.867 and that of thiophene (C4H4S) is 1.065 g/ml. A solution is made by dissolving 10.00g thiophene in 250.00ml of toluene. a)Calculate the molarity of the solution
b)Assuming the volume are addictive ,calculate the molarity of the solution
Answer:
Calcular la molaridad de una solución que se preparó disolviendo 14 g de KOH en suficiente
agua para obtener 250 mL de solución. (masa molar del KOH = 56 g/mol).
Resolución: de acuerdo a la definición de “molaridad” debemos calcular primero, el número de mol de soluto (KOH) que
se han disuelto en el volumen dado, es decir, “se transforma g de soluto a mol de soluto” por medio de la masa molar,
así:
56 g de KOH 14 g de KOH
----------------- = ------------------- X = 0,25 mol de KOH
1 mol X
Ahora, de acuerdo con la definición de molaridad, el número de mol debe estar contenido en 1000 mL (o 1 L) de
solución, que es el volumen estándar para esta unidad de concentración, lo que se determina con el siguiente planteamiento:
0,25 mol X
----------------------- = ------------------------- X = 1 mol de KOH
250 mL de solución 1000 mL de solución
Explanation:
Where do reactions in a solid generally take place?
A. At the center of the solid.
B. All throughout the solid
C. Only on opposite sides of the solid due to repelling forces.
D. On the surface of the solid.
Answer:
It's D. On the surface of the solid.
Explanation:
If the reactant is a solid, the surface area of the solid will impact how fast the reaction goes. This is because the two types of molecule can only bump into each other at the liquid solid interface, i.e. on the surface of the solid. So the larger the surface area of the solid, the faster the reaction will be.
An ice cube, measured at 260 Kelvin, is dropped into a cup of tea that is 350 Kelvin. The temperature of the tea is recorded every 30 seconds and shows the temperature dropping for 4 minutes. After 4 minutes the temperature stays steady at 300 Kelvin. What is this called?
A. Thermal equilibrium
B. Specific heat capacity
C. Latent heat
D. Temperature transfer
Answer:
Specific Heat Capacity
What must happen to uranium before it can be used as a fuel source?
Answer: Uranium enrichment. Uranium is used to fuel nuclear reactors; however, uranium must be enriched before it can be used as fuel. Enriching uranium increases the amount of uranium-235 (U235) that can sustain the nuclear reaction needed to release energy and produce electricity at a nuclear power plant.
convert 100kcals to kilojoules
Answer:
Explanation:
418.4kj is the correct answer
A solution is made by dissolving 0.565 g of potassium nitrate in enough water to make up 250. mL of solution. What is the molarity of this solution?
Please explain and show work.
[tex]\\ \large\sf\longmapsto KNO_3[/tex]
[tex]\\ \large\sf\longmapsto 39u+14u+3(16u)[/tex]
[tex]\\ \large\sf\longmapsto 53u+48u[/tex]
[tex]\\ \large\sf\longmapsto 101u[/tex]
[tex]\\ \large\sf\longmapsto 101g/mol[/tex]
Now
[tex]\boxed{\sf No\:of\:moles=\dfrac{Given\:mass}{Molar\:mass}}[/tex]
[tex]\\ \large\sf\longmapsto No\:of\:moles=\dfrac{0.565}{101}[/tex]
[tex]\\ \large\sf\longmapsto No\:of\:moles=0.005mol[/tex]
We know
[tex]\boxed{\sf Molarity=\dfrac{Moles\:of\:solute}{Vol\:of\:Solution\:in\:L}}[/tex]
[tex]\\ \large\sf\longmapsto Molarity=\dfrac{0.005}{\dfrac{250}{1000}L}[/tex]
[tex]\\ \large\sf\longmapsto Molarity=\dfrac{0.005}{0.250}[/tex]
[tex]\\ \large\sf\longmapsto Molarity=0.02M[/tex]
[tex] \: \: \: \: \: \: \: \: \: [/tex]
15.27
The following equilibria were attained at 823 K:
COO(s) + H2() Co(s) + H2O(g) K = 67
COO(s) + CO(8) = Co(s) + CO2(8) K = 490
Based on these equilibria, calculate the equilibrium con-
stant for
H2(g) + CO2(g) = CO(g) + H2O(g) at 823 K.
The equilibrium constant for the reaction is K = 0.137
We obtain the equilibrium constant considering the following equilibria and their constants:
COO(s) + H₂(g) → Co(s) + H₂O(g) K₁ = 67
COO(s) + CO(g) → Co(s) + CO₂(g) K₂ = 490
We write the first reaction in the forward direction because we need H₂(g) in the reactants side:
(1) COO(s) + H₂(g) → Co(s) + H₂O(g) K₁ = 67
Then, we write the second reaction in the reverse direction because we need CO₂(g) in the reactants side. Thus, the equilibrium constant for the reaction in the reverse direction is the reciprocal of the constant for the reaction in the forward direction (K₂):
(2) Co(s) + CO₂(g) → COO(s) + CO(g) K₂ = 1/490
From the addition of (1) and (2), we obtain:
COO(s) + H₂(g) → Co(s) + H₂O(g) K₁ = 67
+
Co(s) + CO₂(g) → COO(s) + CO(g) K₂ = 1/490
-------------------------------------------------
H₂(g) + CO₂(g) → CO(g) + H₂O(g)
Notice that Co(s) and COO(s) are removed that appear in the same amount at both sides of the chemical equation.
Now, the equilibrium constant K for the reaction that is the sum of other two reactions is calculated as the product of the equilibrium constants, as follows:
K = K₁ x K₂ = 67 x 1/490 = 67/490 = 0.137
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It is advised that the bromobenzene solution be added slowly to the magnesium-ether solution so that it isn't present in a high concentration, thus reducing the amount of by-product formed. What is the by-product
Answer:
Biphenyl
Explanation:
The reaction of bromo benzene with magnesium-ether solution yields a Grignard reagent.
The byproduct of this reaction is biphenyl. It is formed when two unreacted bromobenzene molecules are coupled together.
Hence, It is advised that the bromobenzene solution be added slowly to the magnesium-ether solution so that it isn't present in a high concentration, thus reducing the amount of biphenyl by-product formed.
HBr can be added to an alkene in the presence of peroxides (ROOR). What function does the peroxide serve in this reaction
Answer:
Radical chain initiator
Explanation:
The peroxide here serves as a radical chain initiator. In the field of chemistry the radical initiatives are those substances that are used in industrial processes like polymer synthesis. These initiatives have weak bonds generally and they're mostly used to create free radicals. These radicals are atoms that have odd numbers of electrons. Peroxide is an example of such.
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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Determine what product will be produced at the negative electrode for the following reaction:
2KCl(aq) + 2H20(1) -> H2(g) + Cl2(g) + 2KOH(aq)
A. H2
B. Cl2
с. КОН
D. K
Answer:
Choice A. [tex]\rm H_{2}[/tex] would be produced at the negative electrode.
Explanation:
Ionic equation for this reaction:
[tex]2\, {\rm K^{+}} + 2\, {\rm Cl^{-}} + {2\, \rm H_{2} O} \to {\rm H_{2}} + {\rm Cl_{2}} + 2\, {\rm K^{+}} + {\rm 2\, OH^{-}}[/tex].
Net ionic equation:
[tex]2\, {\rm Cl^{-}} + 2\, \rm H_{2} O} \to {\rm H_{2}} + {\rm Cl_{2}} + 2\, {\rm OH^{-}}[/tex].
Half-equations:
[tex]2\, {\rm Cl^{-}} \to {\rm Cl_{2}} + 2\, {e^{-}}[/tex].
(Electrons travel from the solution to an electrode.)
[tex]2\, {\rm \overset{+1}{H}_{2} O} + 2\, {e^{-}} \to \overset{0}{\rm H}_{2} + 2\, {\rm O\overset{+1}{H}\!^{-}}[/tex].
(An electrode supply electrons to the solution to reduce some of the [tex]\rm H[/tex] atoms from [tex]\rm H_{2}O[/tex].)
In a DC circuit, electrons always enter the circuit from the negative terminal of the power supply and return to the power supply at the positive terminal.
The negative electrode is connected to the negative terminal of the power supply. Electrons from the power supply would flow into the solution through this electrode.
This continuous supply of electrons at the negative electrode would drive a reduction half-reaction. In this question, that corresponds to the reduction of water: [tex]2\, {\rm \overset{+1}{H}_{2} O} + 2\, {\rm e^{-}} \to \overset{0}{\rm H}_{2} + 2\, {\rm O\overset{+1}{H}\!^{-}}[/tex]. Hence, [tex]\rm H_{2}[/tex] would be produced at the negative electrode.
Conversion Problem (show all work):
1. A patient required 3.0 pints of blood during surgery. How many liters does this correspond
to? Show all work. Use conversion factors available in the text or the exam packet. (4)
1.42liters, which is equivalent to 3pints, of blood is required for the surgery
Pints is a unit of measurement for volume in the United States. However, it can be converted to litres using the following equation:1 US pint = 0.473 liters
Hence, according to this question which states that a patient required 3.0 pints of blood during surgery. This means that the patient required:3 × 0.473
= 1.419 liters of blood for the surgery
1.42liters, which is equivalent to 3pints, of blood is required for the surgeryLearn more at: https://brainly.com/question/24168664
Convert the concentration of 0.700 M Na2SO4 to g/mol
To convert from mass concentration to molar concentration we use the formula;
Mass concentration = molar concentration * molar mass
Molar concentration of Na2SO4 = 0.700 M
Molar mass of Na2SO4 = 2(23) + 32 + 4(16) = 142 gmol-1
Hence;
Mass concentration = 0.700 M * 142 gmol-1
Mass concentration = 99.4 g/mol
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Arrange the following compounds in order of increasing reactivity (least reactive first.) to electrophilic aromatic substitution:.
Bromobenzene Nitrobenzene Benzene Phenol
a. Bromobenzene < Nitrobenzene < Benzene < Phenol
b. Nitrobenzene < Bromobenzene < Benzene < Phenol
c. Phenol < Benzene < Bromobenzene < Nitrobenzene
d. Nitrobenzene < Benzene < Bromobenzene < Phenol
Answer:
Nitrobenzene < Bromobenzene < Benzene < Phenol
Explanation:
Aromatic compounds undergo electrophilic aromatic substitution reaction in the presence of relevant electrophiles. Certain substituents tend to increase or decrease the tendency of an aromatic compound towards electrophilic aromatic substitution reaction.
Substituents that increase the electron density around the ring such as in phenol tends to make the ring more reactive towards electrophilic substitution. Halogens such as bromine has a -I inductive effect as well as a +M mesomeric effect.
However the -I(electron withdrawing effect) of the halogens supersedes the +M electron donation due to mesomeric effect.
Putting all these together, the order of increasing reactivity of the compounds towards electrophilic aromatic substitution is;
Nitrobenzene < Bromobenzene < Benzene < Phenol
What type of bond is present in NBr?
Answer:
Covalent bonding and non-covalent bonding
A Grignard reagent is prepared by reacting trans-1-bromo-1-butene with magnesium. What are the products of the reaction when this reagent is reacted with: a. Ethanol
Solution :
A Grignard compound or a Grignard reagent is defined as a chemical compound having a generic formula of R−Mg−X.
Here, X = halogen
R = organic group
The Grignard reagents are obtained by treating the organic halide with a magnesium metal.
In the context, when trans-1-bromo-1-butene is reacted with magnesium, a Grignard reagent is produced.
When this Grignard reagent is reacted with an ethanol, the following product is obtained in the attachment :
A substance is tested and has a pH of 7.0. How would you classify it?
Four atoms and/or ions are sketched below in accordance with their relative atomic and/or ionic radii. Which of the following sets of species are compatible with the sketch?
Explain. (a) C,Ca2+,Cl−,Br−;
(b) Sr4, Cl,Br−,Na+
(d) Al,Ra2+,Zr2+
(c) Y,K,Ca,Na+, Mg2+;
e) Fe,Rb,Co,Cs
Answer:
Hence the correct option is an option (b) Sr4, Cl,Br−,Na+.
Explanation:
Bromine and chlorine belong to an equivalent group. As we go down the group the dimensions increases which too there's a charge on the bromine atom. therefore the size of the Br- is going to be larger in comparison to the chlorine atom.
Sr atom is within the second group, and also it's below the above-mentioned atoms.so Sr is going to be the larger one among all the atoms.
Sodium and chlorine belong to an equivalent period .size decrease from left to right. but due to the charge on sodium its size decreases and there's an opportunity that Na+ size could be adequate for Cl.
Here we finally assume that two atoms are of an equivalent size (Na+ and Cl) which are less in size compared to the opposite two(Sr and Br-) during which one is greater (Sr)and the opposite is smaller(Br-).
HELP ASAP 15 POINTS
Why was Dalton's theory of the atom incorrect?
A. Dalton theorized that atoms were indivisible but they are actually made of smaller parts.
B. Dalton theorized that had negative charges spread throughout them but they are actually in electron shells.
C. Dalton' theory was correct.
D. Dalton theorized that atoms were too small to see but they are not.
Answer:
Answer is A.
Explanation:
The indivisibility of an atom was proved wrong: an atom can be further subdivided into protons, neutrons and electrons. According to Dalton, the atoms of same element are similar in all respects. However, atoms of some elements vary in their masses and densities. These atoms of different masses are called isotopes. :)
