Answer:
Na₂CO₃•H₂O
Explanation:
After it is heated, the remaining mass is the mass of sodium carbonate.
30.2 g Na₂CO₃
Mass is conserved, so the difference is the mass of the water:
35.4 g − 30.2 g = 5.2 g H₂O
Convert masses to moles:
30.2 g Na₂CO₃ × (1 mol Na₂CO₃ / 106 g Na₂CO₃) = 0.285 mol Na₂CO₃
5.2 g H₂O × (1 mol H₂O / 18.0 g H₂O) = 0.289 mol H₂O
Normalize by dividing by the smallest:
0.285 / 0.285 = 1.00 mol Na₂CO₃
0.289 / 0.285 = 1.01 mol H₂O
The ratio is approximately 1:1. So the formula of the hydrate is Na₂CO₃•H₂O.
Na₂CO₃•H₂O
Further explanationGiven:
A 35.40 g hydrate of sodium carbonate, Na₂CO₃•nH₂O, is heated to a constant mass.Its final weight is 30.2 g.Question:
What is the formula for the hydrate?
Problem-solving:
We will solve problems related to The Law of Definite Proportion (Proust's Law).
"The ratio of the masses of elements in each compound is always constant. Put differently, a given compound invariably contains a similar proportion of elements by mass."
The heating reaction of the hydrate of sodium carbonate is as follows:
[tex]\boxed{ \ Na_2CO_3.nH_2O \xrightarrow{\text{heat}} Na_2CO_3 + nH_2O \ }[/tex]
Condition:
Before heating: 35.40 g of Na₂CO₃•nH₂O (hydrate)After heating: 30.20 g of Na₂CO₃ (anhydrate)The mass of H₂O that has left the compound is [tex]\boxed{ \ 35.40 - 30.20 = 5.2 \ g \ }[/tex][tex]\boxed{ \ Na_2CO_3.nH_2O \xrightarrow{\text{heat}} Na_2CO_3 + nH_2O \ }[/tex]
35.4 g 30.2 g 5.2 g
We want to determine the amount of water (with the symbol n) so that the formula for the hydrate can be known.
Recall that [tex]\boxed{ \ Moles = \frac{Mass \ (g)}{Mr} \ }[/tex]
Let us prepare the number of moles of Na₂CO₃ and H₂O respectively.
Mr Na₂CO₃ = 106 g/mol ⇒ [tex]\boxed{ \ moles = \frac{30.2}{106} \rightarrow \boxed{ \ 0.285 \ } \ }[/tex] Mr H₂O = 18 g/mol ⇒ [tex]\boxed{ \ moles = \frac{5.2}{18} \rightarrow \boxed{ \ 0.289 \ }\ }[/tex]Finally, we use the mole ratio to write the formula. Find the water-to-anhydrate mole ratio.
[tex]\boxed{ \ Na_2CO_3 \ : \ H_2O = 1 \ : \ n \ }[/tex]
[tex]\boxed{ \ H_2O \ : \ Na_2CO_3 = n \ : \ 1 \ }[/tex]
[tex]\boxed{ \ n \ : \ 1 = 0.289 \ : \ 0.285 \ }[/tex]
[tex]\boxed{ \ n = \frac{0.289}{0.285} \times 1 \ }[/tex]
Thus, the value of n after rounding is [tex]\boxed{ \ n = 1 \ }[/tex]
Substitute n = 1 into Na₂CO₃•nH₂O.
Therefore, the formula for the hydrate is [tex]\boxed{\boxed{ \ Na_2CO_3.H_2O \ }} [/tex]
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A 50°C solution has a pH of 3.30. At this temperature, Kw = 5.48 x 10 9. What is the pOH of the solution?
Answer:
9.93
Explanation:
Your value for Kw is incorrect. The correct value is 5.48 × 10^-14.
pH + pOH = pKw
3.30 + pOH = -log(5.84 × 10^-14) = 13.23
pOH = 13.23 - 3.30 = 9.93
The pOH of the solution is 9.93.
The pOH of the solution is 10 .
Given that, the pH of the solution is 3.30, we also know that;
pH = - log[H^+]
Hence;
[H^+] = Antilog (-3.3)
[H^+] = 5.0 × 10^-4 M
But;
Kw = [H^+] [OH^-]
[OH^-] = Kw/[H^+]
The accurate value of Kw is 5.48 × 10^-14 not 5.48 x 10 9
[OH^-] = 5.48 x 10^-14/ 5.0 × 10^-4
[OH^-] = 1.1 x 10^-10 M
pOH = - log[1.1 x 10^-10 M]
pOH = 10
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is mercury a solution
Answer:
No.
Explanation:
Mercury is not a solution. It is a detonator.
Assume you add 5 g of Nacl to a beaker and add water until the volume of the solution reaches 4 L. Calculate the concentration of salt in water in g/L and mol/L.
Answer:
1.25 g/L.
0.0214 mol/L.
Explanation:
Concentration in g/L = 5/4
= 1.25 g/L (answer).
As for mol / L we need to know the molar mass of salt.
It is 22.99 + 35.45 = 58.44.
So in mol/L it is 1.25 / 58.44
= 0.0214 mol/L.
How many grams of CaCl2
are needed to make 344.9
g of a solution that is 32.0
% (m/m) CaCl2
in water? Note that mass is not technically the same thing as weight, but % (m/m) has the same meaning as % (w/w).
grams CaCl2=
g
How many grams of water are needed to make this solution?
grams H2O=
Answer:
[tex]\boxed{\text{110.4 g of CaCl$_{2 }$ and 234.5 g of water}}[/tex]
Explanation:
1. Mass of CaCl₂
[tex]\text{Let m = mass of CaCl}_{2}\\\\\begin{array}{rcl}\text{Mass percent} & = & \dfrac{\text{Mass of CaCl}_{2}}{\text{Total mass}} \times 100 \%\\\\32.0 \% & = & \dfrac{m}{\text{344.9 g}} \times 100 \% \\\\\text{32.0 $\times$ 344.9 g} & = & 100 m\\\\m & = &\dfrac{\text{32.0 $\times$ 344.9 g}}{100}\\\\ & = &\textbf{110.4 g}\\\end{array}\\\text{You need $\boxed{\textbf{110.4 g}}$ of calcium chloride}[/tex]
2. Mass of water
[tex]\text{Let m = mass of water}\\\begin{array}{rcl}\\\text{Mass of water + mass of CaCl}_{2} & = & \text{Mass of solution}\\m + 110.4 & = & 344.9\\m & = &\mathbf{234.5}\\\end{array}\\\text{The mass of water needed is $\boxed{\textbf{234.5 g}}$}[/tex]
Consider the chemical reaction below.
Zn(s)+ 2H*(aq) → Zn2+ (aq) + H2(g)
Which half reaction correctly represents reduction for this equation?
Zn(s) → Zn2+ (aq)+2e
2H* (aq)+2e → H2(g)
Zn(s) → Zn?- (aq)+e"
2H* (aq)+e™ → H2(g)
Answer: [tex]2H^++2e^-\rightarrow H_2(g)[/tex]
Explanation:
Oxidation-reduction reaction or redox reaction is defined as the reaction in which oxidation and reduction reactions occur simultaneously.
Oxidation reaction is defined as the reaction in which a substance looses its electrons. The oxidation state of the substance increases.
Reduction reaction is defined as the reaction in which a substance gains electrons. The oxidation state of the substance gets reduced.
For the given reactio:
[tex]Zn(s)+2H^+\rightarrow Zn^{2+}+H_2[/tex]
On reactant side:
Oxidation state of zinc= 0
Oxidation state of hydrogen = +21
On product side:
Oxidation state of zinc = +2
Oxidation state of hydrogen = 0
The oxidation state of hydrogen reduces from +1 to 0, it is getting reduced. Thus, it is getting reduced and it undergoes reduction reaction
Hence, the correct answer is [tex]2H^++2e^-\rightarrow H_2(g)[/tex]
Answer:
2H+(aq) + 2e– → H2(g) or B.)
on edge 2023
why does matter change from one phase to another
Answer:
the state of matter depends on its temperature and pressure. example, at constant pressure of 1atm (atmospheric pressure), water at 100 degrees Celsius is vapor, and at different phases at different temperature. Note that's at pressure other than 1atm, water will not boil (be vaporized) at 100 degrees Celsius, it could be lesser or higher(depending on whether pressure is increased or decreased).
Therefore, the state of mater changes with respect to temperature and pressure action on it.
Which describes the fourth state of matter known as plasma?
A It is a liquid containing nuclei and electrons.
B It is a gas containing nuclei and electrons.
C It is a liquid containing electrons created by fusion.
D It is a gas containing nuclei created by fusion.
Answer:
the answer is letter B. it is a gas containing nuclei and electrons.
B. It is a gas containing nuclei and electrons.
What is the fourth state of matter?Plasma is called the fourth state of matter. It is a state of matter in which an ionized substance turns into distinctly electrically conductive to the point that long-range electric and magnetic fields dominate its behavior.
A plasma is an ionized gas.a gas into which sufficient energy is provided to free electrons from atoms or molecules to allow both species, ions, and electrons, to coexist. Plasma is the fourth state of matter.Learn more about Plasma here
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Which of the following types of energy does an object have because of its motion?
Chemical energy
Gravitational energy
Kinetic energy
Potential energy
Answer: Kinetic energy
Explanation:
Chemical energy is the energy stored in the bonds of molecules.
Gravitational energy is the potential energy held by an object because of its higher position compared to a lower position.
Kinetic energy is the energy possessed by a body by virtue of its motion.
Potential energy is the energy possessed by a body by virtue of its position.
Thus kinetic energy is the energy associated with an object because of its motion.
What does this equation, 2 C(s) + O 2(g) ® 2 CO(g), tell us?
A) the number of atoms of each kind in reactants and products is the same
B) carbon monoxide (CO) is a product
C) two atoms of carbon undergo reaction
D) all of these
Answer:
D. All of these.
Explanation:
For an equation to be balanced the number of atoms of each kind in the reactants and the products should be the same.
Then from this equation, CO is a product.
Last, two carbon atoms undergo reaction with the oxygen molecule for complete reaction to occur. Each atom combines with one oxygen atom.
Answer:
D) All of these
Explanation:
[tex]2 C(s) + O_2 (g) > 2 CO(g)[/tex]
Reactant side (Left side) Element Product side (Right side)
2 C 2
2 O 2
Balanced!!!
Balancing is making the number of atoms of each element same on both the sides (reactant and product side).
To find the number of atoms of each element we multiply coefficient × subscript
For example [tex]5 Ca_1 Cl_2[/tex] contains
5 × 1 = 5 ,Ca atoms and
5 × 2 = 10, Cl atoms
If there is a bracket in the chemical formula
For example [tex]3Ca_3 (P_1 O_4 )_2[/tex] we multiply coefficient × subscript × number outside the bracket.......... to find the number of atoms (Please note: 3 is the coefficient, and if there is no number given then 1 will be the coefficient )
So
3 × 3 = 9 , Ca atoms
3 × 1 × 2 = 6, P atoms
3 × 4 × 2 = 24, O atoms are present.
Which element has an atomic number of 16?
Answer:
Sulfur
Explanation:
the atomic number is the number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table
Sulfur has 16 protons in its nucleus
The element with an atomic number of 16 is sulfur.
How do we explain?Sulfur is a chemical element that has an atomic number of 16. It is represented by the symbol "S" on the periodic table.
Sulfur is a nonmetal and belongs to Group 16, also known as the chalcogens, on the periodic table. It is located in the third period. It is classified as a multivalent element, meaning it can form compounds with various oxidation states.
In its pure form, sulfur is a yellow, brittle solid. It is known for its distinctive odor, often described as being similar to rotten eggs. Sulfur is found in various minerals and is also a component of many natural resources such as coal, petroleum, and natural gas.
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Determine the number of moles. 2.4x10^24 atoms of Fe
Which cohesive forces are the strongest in water?
A.) London dispersion forces
B.) dipole interactions
C.) hydrogen bonding interactions.
D.) All intermolecular forces in water are equally strong.
Please help me! I think the answer to this is C because gas produced from liquid has the greatest release in entropy, right? And C is the only option producing gas. Please help me out! Is C the right answer or which one is?
The systems that shows the greatest increase in entropy is -
a.2H2 + O2®2H2O
b.NaCl ®Na+1 + Cl-1
c.2H2O ®2H2 + O2
d.AgCl3®Ag+3 + 3Cl-1
Answer:
c. 2H₂O → 2H₂ + O₂
Explanation:
Entropy is the state of randomness or disorderliness of the particles of a system. The more random and disorderly a system is, the more its entropy. When the physical state of matter changes, there is a considerable change in the entropy of such a system.
The increasing order of entropy is as listed below:
Solid < liquid < gas
Gases have the highest randomness in all states of matter.
From the equation of the reaction in option C, we see that water is going into the gaseous phase. The products of the reaction are hydrogen and oxygen gases. This is an increase in entropy.
Reaction B and D produced ions which are in aqeous solutions. They move from originally solid sate to a liquid phase.
Reaction A takes gases and turns them into water. This is a decrease in entropy.
An atom of boron has an atomic number of 5 and an atomic mass of 11. The atom contains
5 protons, 6 electrons, and 5 neutrons.
11 protons, 11 electrons, and 5 neutrons.
5 protons, 5 electrons, and 6 neutrons.
11 protons, 6 electrons, and 6 neutrons.
Answer:
5 protons, 5 electrons, and 6 neutrons
An atom of boron has 5 protons, 5 electrons, and 6 neutrons. This composition aligns with its atomic number of 5 and an atomic mass of 11. Therefore, the correct option is the one with 5 protons, 5 electrons, and 6 neutrons.
To determine the composition of a boron atom, we need to understand the concepts of atomic number and atomic mass. Boron has an atomic number of 5, which means it has 5 protons. The atomic mass of boron is approximately 11, which is the sum of the number of protons and neutrons.
Given these details, the correct configuration of a boron atom with an atomic number of 5 and an atomic mass of 11 is:
5 protons5 electrons6 neutronsThus, an atom of boron has 5 protons, 5 electrons, and 6 neutrons. This corresponds to the configuration that meets both the atomic number and atomic mass criteria as mentioned earlier.
How many grams of PbBr2 will precipitate when excess CrBr; solution is added to 60.0 mL of 0.551 M Pb(NO3)2 solution?
3Pb(NO3)2(aq) + 2CrBr3(aq) –>3PbBrz(s) + 2Cr(NO3)(aq)
Answer:
5.48 g
Explanation:
M: 367.01
3Pb(NO3)2(aq) + 2CrBr3(aq) → 3PbBr2(s) + 2Cr(NO3)3(aq)
1. Moles of Pb(NO3)2
n = 30.0 mL × (0.551 mmol/1 mL) = 16.53 mmol Pb(NO3)2
2. Moles of PbBr2
n = 16.53 mmol Pb(NO3)2 × (3 mmol PbBr/3 mol Pb(NO3)2)
= 16.53 mmol PbBr2
(3) Mass of PbBr2 formed
m = 16.53 mmol × (367.01 mg/1 mol) = 6067 mg
(4) Mass of PbBr2 in solution
PbBr2 is slightly soluble, so a significant amount will remain in solution.
Its solubility is 973 mg/100 mL.
Mass of dissolved PbBr2 = 60.0 mL × 973 mg/100 mL = 584 mg
(5) Mass of precipitate
Mass of precipitate = mass of PbBr2 formed - mass of PbBr2 in solution
m = 6067 mg - 584 mg = 5480 mg = 5.48 g
The mass of precipitate is 5.48 g.
The mass of PbBr2 precipitate produced is 12.1 g.
The equation of the reaction is;
3Pb(NO3)2(aq) + 2CrBr3(aq) –>3PbBr2(s) + 2Cr(NO3)3(aq)
Number of moles of Pb(NO3)2 = 60.0/1000 L × 0.551 M = 0.0331 moles
From the information in the question, we already know that Pb(NO3)2 is the limiting reactant and CrBr3 is the reactant in excess.
From the equation of the reaction;
3 moles of Pb(NO3) yields 3 moles of PbBr2
0.0331 moles of Pb(NO3) yields 0.0331 moles × 3 moles/3 moles
= 0.0331 moles of PbBr2
Mass of PbBr2 = number of moles × molar mass
Mass of PbBr2 = 0.0331 moles × 367 g/mol= 12.1 g
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Imagine you are a detective examining a crime scene. You are trying to
identify the person who committed the crime, so you collect many samples at
the crime scene. Which sample would be most useful in identifying the
person who committed the crime?
O
A. A newspaper left at the crime scene
O
B. An ant found crawling across the crime scene
O
C. Pieces of hair found at the crime scene
O
D. Gravel and dirt on the ground at the crime scene
SUBMIT
Answer:
C. pieces of hair found at the crime scene.
Explanation:
using the pieces of hair, you can get the DNA of the person. This will give u a better lead in solving the crime.
Hope it helps u ....
Answer:
C. Pieces of hair found at the crime scene.
Explanation:
Pieces of hair found at the crime scene is more useful to find the criminal who committed the crime, because it helps in indetifying criminal's DNA through the process of DNA fingerprinting. The hair is analyzed by the chemical makeup of the hair and extracting DNA from the hair follicle, pieces of hair must have hair follicle attached to find DNA of the criminal.
Nuclear DNA can be successfully extracted from the hair root. Cut hair samples are useless without hair follicle attached. Its DNA will be useful only few months for testing. The DNA last in hairs about 1,000 to 10,000 years.
what is the equilibrium expression for the reatcion bellow
2SO3(g)<=>O2(g)+2SO2(g)
The equilibrium expression for the given reaction 2SO3(g) <=> O2(g) + 2SO2(g) is Ke = [SO₃]² / ([SO₂]² [O₂]).
Explanation:The equilibrium expression for the given reaction is Ke = [SO₃]² / ([SO₂]² [O₂]).
Ke represents the equilibrium constant, which is a measure of the extent to which a reaction reaches equilibrium. In this case, the equilibrium constant is calculated by taking the square of the concentration of SO₃ and dividing it by the product of the squares of the concentrations of SO₂ and O₂.
For example, if the concentrations at equilibrium are [SO₂] = 0.90 M, [O₂] = 0.35 M, and [SO₃] = 1.1 M, the value of the equilibrium constant, Ke, can be calculated as Ke = (1.1)² / ((0.90)² (0.35)).
Determine what is missing from this neutralization reaction: −−−−+KCl→AgCl+KNO3
A. Ag2KN
B. AgNO3
C. KN2O
D. NHO3
Answer:
B. AgNO₃
Explanation:
If the products contain Ag, Cl, K, and NO₃, then this means that these were also the reactants. Remember that matter cannot be created nor destroyed in a chemical reaction, so whatever elements in the reactants were used, would be found in the products. In other words, an element does not change into another.
AgNO₃ + KCl → AgCl + KNO₃
Consider the proportionality below.
PV ont
What does this best represent?
Dalton's law
Charles's law
ideal gas law
combined gas law
Answer:
Ideal gas law
Explanation:
The expression is the ideal gas law when properly written;
PV = nRT
where P is the pressure of the gas
V is the volume of the gas
n is the number of moles of the gas
R is the gas constant
T is the temperature
The ideal gas law is derieved from the three major gas laws;
--- Boyle's law, Charles's law and Avogadro's law
Which statement is the best description of a chemical bond?
A. A chemical bond connects 2 different molecules.
B. A chemical bond holds atoms together.
c. A chemical bond turns molecules into atoms.
D. A chemical bond identifies atoms in a molecule.
Answer:
B. is the correct answer
A chemical bond holds atoms together,is the statement that description of a chemical bond.
What is meant by chemical bond?A chemical bond is what holds atoms together in molecules. Bonds arise from the electrostatic forces between positively charged atomic nuclei and negatively charged electrons (the positions of which in space are determined by quantum mechanics).A chemical bond holds atoms together,is the statement that description of a chemical bond.
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Which molecular solid would have the highest melting point?
O
A. One with induced dipole attractions
O
B. One that has hydrogen bonding
O
C. One made of nonpolar molecules
O
D. One with dipole-dipole attractions
Answer:
Choice B. The solid with hydrogen bonding.
Assumption: the molecules in the four choices are of similar sizes.
Explanation:
Molecules in a molecular solid are held intact with intermolecular forces. To melt the solid, it is necessary to overcome these forces. The stronger the intermolecular forces, the more energy will be required to overcome these attractions and melt the solid. That corresponds to a high melting point.
For molecules of similar sizes,
The strength of hydrogen bonding will be stronger than the strength of dipole-dipole attractions.The strength of dipole-dipole attractions (also known as permanent dipole) will be stronger than the strength of the induced dipole attractions (also known as London Dispersion Forces.)That is:
Strength of Hydrogen bond > Strength of Dipole-dipole attractions > Strength of Induced dipole attractions.
Accordingly,
Melting point due to Hydrogen bond > Melting point due to Dipole-dipole attractions > Melting point due to Induced Dipole attractions.
Induced dipole is possible between all molecules.Dipole-dipole force is possible only between polar molecules.Hydrogen bonds are possible only in molecules that contain [tex]\rm H[/tex] atoms that are bonded directly to atoms of [tex]\rm F[/tex], [tex]\rm O[/tex], or [tex]\rm N[/tex].As a result, induced dipoles are the only force possible between molecules of the solid in choice C. Assume that the molecules are of similar sizes, such that the strengths of induced dipole are similar for these molecules.
Melting point in choice B > Melting point in choice D > Melting point in choice A and C.
Answer:
B. One that has hydrogen bonding
Which of these statements best describes the formula unit for a compound made from Mg and Cl?
It is MgCl2 because the total negative charge on Cl is one.
It is Mg2Cl because the total negative charge on Mg is one.
It is MgCl2 because the total positive charge on Mg is two.
It is Mg2Cl because the total positive charge on Mg is two.
WILL MARK BRAINLIEST
Answer:
It is MgCl₂ because the total positive charge on Mg is two
Explanation:
The bond between the atoms that makes up the formula unit of the compound is an ionic bond. This bond involves the transfer of electrons between atoms.
Mg is in the second group on the period on the periodic table. It has two valence electrons and would readily lose it to have a stable atomic configuration like those of noble gases. This leaves magnesium with a net positive charge of 2. Each chlorine atom gains one electron to achieve their own octet.
The formula unit of a substance composed of magnesium (Mg) and chlorine (Cl) is [tex]MgCl_2.[/tex] Therefore, the correct option are C and D.
This is due to the fact that while chlorine has a negative charge of -1, magnesium has a positive charge of +2. Two chloride ions combine with one magnesium ion to equalize the charges and provide electrical neutrality.
The two chlorine ions combine to provide a total negative charge of -2 because each chlorine ion adds a charge of -1. The negative charge of the chlorine ions is balanced by the +2 charge of the magnesium ions. As a result, the molecule formed by the combination of one magnesium ion and two chlorine ions is represented by the formula unit [tex]MgCl_2[/tex].
Therefore, the correct option are C and D.
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what name did wegener give to the single large landmass composed of all continents
Answer:
The large landmass was named Pangea
Answer:
The names of all continents is Pangaea given by Alfred Wegener in 1912
Explanation:
The name Pangaea or Pangea is derived from the Greek pan that in english means Whole and Gaia that in english means Land. The idea was not new because before Wegener, other scientist have proposed the idea of a huge landmass and then the separation by continents. but Wegener was the first to use the term continental drift.
The continental drift means that the continents are moving form each other since millions of years due to the mantle convection. This theory has been replaced by tectonic plate theory.
Which is a fossil fuel?
A.nuclear
B.Biomass
C.geothermal
D.coal
Answer:
Coal
Explanation:
Coal is composed of the remains of dead animals and plants, being pressed down over the course of thousands of years.
(Also can I please have Brainliest? I need it to level up)
Answer:
coal
Explanation:
a fossil fuel is a general term for buried combustible geologic deposits of organic materials formed from decayed plants and animals. hope this helps i took physical science.
why is concentrated sulphuric acid is weak acid
Answer:
Sulfuric acid is a strong acid in any state
Explanation:
You may be thinking if the definition that a weak acid produces relatively few ions in aqueous solution,
If you have 100 % sulfuric acid, there is no water, so the definition does not apply.
Commercial sulfuric acid contains about 2 % water. The sulfuric acid in that small amount of water consists of about 99 % HSO₄⁻ and 1 % SO₄²⁻. The acid is almost completely ionized.
Sulfuric acid is a strong acid.
Rate or Reaction Past Exam Questions 2
10 Fatimah investigates the reaction between sodium hydrogencar
acid.
reaction between sodium hydrogencarbonate and dilute hydrocrc
She always adds 0.5g of sodium hydrogencarbonate to 20 cm of dilute hydrochia
She measures the time it takes for the reaction mixture to stop bubbling.
This is called the reaction time.
She does five different experiments.
She keeps the temperature the same.
Each experiment uses a different concentration of acid.
Look at a graph of her results.
1004
60F
reaction time
in seconds
0.5
1.5
2
.0
2.5
1.0
concentration in mol/dms
Fatimah concludes that as the concentration of acid increases, the rate of reaction increases.
Explain, with a reason, whether the results support Fatimah's conclusion.
Use the reacting particle model to explain Fatimah's results.
The quality of written communication will be assessed in your answer to this question.
The experiment results support Fatimah's conclusion that higher acid concentration increases the reaction rate, based on the reacting particle model and the kinetic molecular theory.
Explanation:Based on the description of the experiment, Fatimah observed that as the concentration of acid increased, the reaction time decreased, indicating that the rate of reaction increased. This can be explained by the reacting particle model, which suggests that with a higher concentration of acid, there are more acid particles in a given volume. This increases the likelihood of effective collisions between acid particles and sodium hydrogencarbonate particles, thereby increasing the rate of reaction.
The relationship between the concentration of reactants and the rate of reaction is explained in kinetic molecular theory. In the case of sodium hydrogencarbonate reacting with hydrochloric acid, producing bubbles of carbon dioxide, we would see a shorter reaction time with higher concentrations of acid. This is due to more frequent and effective collisions, which is consistent with the results as shown in Fatimah's graph. Calculating reaction rate involves the change in concentration of reactants or products over time, which can be reflected in the dynamics of the experiment she conducted.
Give the location of the elements found in the periodic table which have the same number valence electrons.
A. All members in group VIII only
B. All numbers within any group
C. All numbers within any period
D. All the nonmetals
Answer:
B - all numbers within any group (vertical column)
Explanation:
https://en.wikipedia.org/wiki/Valence_electron
Answer:
B - all numbers within any group
Explanation:
Consider the following unbalanced redox reaction:
Cr2O72- (aq) + NO2 (aq) – Cr3+ (aq) + NO3(aq)
What is the oxidizing agent in the reaction?
The oxidizing agent in the reaction Cr2O72- (aq) + NO2 (aq) – Cr3+ (aq) + NO3 (aq) is Cr2O72-, as it is reduced, meaning it accepts electrons, going from a chromium oxidation state of +6 to +3.
Explanation:In a redox reaction, the oxidizing agent is the substance that is reduced, meaning it gains electrons. In the unbalanced reaction: Cr2O72- (aq) + NO2 (aq) – Cr3+ (aq) + NO3(aq), the Cr2O72- ions are reduced to Cr3+ ions.
This is determined through the observation of the oxidation states of the substances before and after the reaction. The oxidation state of chromium in Cr2O72- is +6, while it is +3 in Cr3+. This reduction in oxidation state indicates that Cr2O72- accepted electrons, meaning it is the oxidizing agent in this reaction.
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The salt formed by the reaction of the weak acid hydrocyanic acid, HCN, with the strong base potassium hydroxide is
potassium cyanide, KCN. What is the hydroxide ion concentration of a 0.255 M solution of potassium cyanide at 25 °C
given that the value of for hydrocyanic acid is 4.9 X 10-102
Answer:
2.28 × 10^-3 mol/L
Explanation:
The equation for the equilibrium is
CN^- + H2O ⇌ HCN + OH^-
Ka = 4.9 × 10^-10
KaKb = Kw
4.9 × 10^-10 Kb = 1.00 × 10^-14
Kb = (1.00 × 10^-14)/(4.9 × 10^-10) = 2.05 × 10^-5
Now, we can set up an ICE table
CN^- + H2O ⇌ HCN + OH^-
I/(mol/L) 0.255 0 0
C/(mol/L) -x +x +x
E/(mol/L) 0.255 - x x x
Ka = x^2/(0.255 - x) = 2.05 × 10^-5
Check for negligibility
0.255/(2.05 × 10^-5) = 12 000 > 400. ∴ x ≪ 0.255
x^2 = 0.255(2.05 × 10^-5) = 5.20 × 10^-6
x = sqrt(5.20 × 10^-6) = 2.28 × 10^-3
[OH^-] = x mol/L = 2.28 × 10^-3 mol/L
is when two atoms combine to form a larger atom,
The process of _
releasing energy.
Nuclear fusion is a process where light atomic nuclei merge to form a heavier nucleus, releasing energy due to the mass difference being converted into energy. This reaction powers stars and has potential applications in generating clean energy on Earth.
The process being described is known as nuclear fusion. It occurs when two light atomic nuclei combine to form a larger, heavier nucleus, typically releasing a significant amount of energy. This process explains why fusion is considered a potential source of almost inexhaustible clean energy. In stars, such as our Sun, fusion is the energy-producing process, where hydrogen nuclei fuse under intense pressure and temperature to form helium, outputting immense energy in the process.
In terms of mass, the total mass of the resulting heavier nucleus is slightly less than the sum of the original nuclei. This difference in mass, according to Einstein's equation E = mc2, is converted into energy, which is radiated away. The ability to control nuclear fusion on Earth is a goal of many research programs, as it promises a less hazardous and more abundant alternative to current nuclear fission power plants.