Answer:
a) - 0.2 M
b) - 0.2 M
c)- 0
Explanation:
The chemical formula of copper (II) bromide is CuBr₂. Its molar mass (MM) is calculated as follows:
MM(CuBr₂)= MM(Cu) + (2 x MM(Br) = 63.5 g/mol + (2 x 80 g/mol)= 223.5 g/mol
a). Molarity = moles CuBr₂/1 L solution
moles CuBr₂ = mass/MM = 18.7 g x 1 mol/223.5 g = 0.084 mol
Volume in L = 375 mL x 1 L/1000 mL = 0.375 L
M = 0.084 mol/(0.375 L) = 0.223 M ≅ 0.2 M
b). When is added to water, CuBr₂ dissociates into ions as follows:
CuBr₂ ⇒ Cu²⁺ + 2 Br⁻
We have 1 mol Cu²⁺ (copper (II) cation) per mol of CuBr₂. Thus, the concentration of copper (II) cation is:
0.2 mol CuBr₂ x 1 mol Cu²⁺/mol CuBr₂ = 0.2 M
c). The concentration of acetate anion is 0. There is no acetate anion in the solution (the anion from CuBr₂ is bromide Br⁻).
How does an anion form?
A. An anion forms when a stable atom loses one or more neutrons.
B. An anion forms when a stable atom loses one or more protons.
C. An anion forms when a stable atom gains one or more electrons.
D. An anion forms when a stable atom loses one or more electrons.
How many milliliters of 0.500 M HBr would be required to react with 40.0 mL of 0.300 M Ca(OH)2?
Answer:
48dm³
Explanation:
Given reaction:
Ca(OH)₂ + 2HBr → CaBr₂ + 2H₂O
Parameters:
Concentration of HBr = 0.5M
Volume of Ca(OH)₂ = 40mL
Concentration of Ca(OH)₂ = 0.3M
Solution:
To solve this problem, we are going to use the mole concept. We solve from the known specie to the unknown.
We first find the number of moles of the known specie which is the Ca(OH)₂ ;
number of moles = concentration x volume
number of moles = 0.3 x 40 x 10⁻³ = 0.012moles
From the reaction equation;
1 mole of Ca(OH)₂ requires 2 moles HBr
0.012 moles of Ca(OH)₂ will require 0.012 x 2 = 0.024moles of HBr
Now,
To find the volume of HBr;
Volume = [tex]\frac{number of moles }{concentration}[/tex]
Volume = [tex]\frac{0.024}{0.5}[/tex] = 0.048dm³
In mL;
Volume 0.048 x 1000 = 48dm³
Which pair of elements will form a covalent bond?
A 500. mL gas sample is collected over water at a pressure of 740 mmHg and 25.0 °C. What is the volume of the dry gas at STP?
Answer:
Volume of dry gas at STP = 0.432 liters or 432 ml
Explanation:
Given:
Pressure (P) = 740 mmHg - 24 mmHg = 716 mmHg
Temperature (t) = 25 degrees C + 273 K = 298 K
500 ml = 0.5 l
Find:
Volume of dry gas at STP
Computation:
[P1][V1] / T1 = [P2][V2] / T2
[716][0.5] / 298 K = [760][ x Liters] / 273 K
x = 0.432 Liters
Volume of dry gas at STP = 0.432 liters or 432 ml
For something to be considered
dead, it used to do what?
Answer:
breathe,eat, and drink i guess
Which of the following elements has the largest atomic radius? Bromine, Barium, Magnsium, Zinc
Answer:
Atomic radii vary in a predictable way across the periodic table. As can be seen in the figures below, the atomic radius increases from top to bottom in a group, and decreases from left to right across a period. Thus, helium is the smallest element, and francium is the largest.
Explanation:
27.8 mL solution of 0.797 M HCHO2 with 0.928 M NaOH. What is the pH for the solution at the equivalence point in the titration?
Answer:
8.69 is the pH at the equivalence point
Explanation:
Formic acid, HCHO₂, reacts with NaOH as follows:
HCHO₂ + NaOH → NaCHO₂ + H₂O.
At the equivalence point you will have in the reaction just NaCHO₂ and H₂O. The concentration of NaCHO₂ will be:
Moles: 0.0278L * 0.797mol/L = 0.02216moles
To reach the equivalence point it is necessary to add:
0.02216mol * (1L / 0.928mol) = 0.0239L
Total volume in the equivalence point:
0.0278L + 0.0239L = 0.0517L
Concentration: 0.02216moles / 0.0517L = 0.429M
The equilibrium of NaCHO₂, CHO₂⁻, in water is:
CHO₂⁻(aq) + H₂O(l) ⇄ OH⁻(aq) + HCHO₂(aq)
Where Kb, 5.56x10⁻¹¹ is defined as:
5.56x10⁻¹¹ = [OH⁻] [HCHO₂] / [CHO₂⁻]
In the equilibrium, it is produced X OH⁻ and HCHO₂, and as concentration of NaCHO₂ is 0.429M:
5.56x10⁻¹¹ = [X] [X] / [0.429M]
2.383x10⁻¹¹ = X²
4.88x10⁻⁶ = X = [OH⁻]
As pOH = -log [OH⁻]
pOH = 5.31
And pH = 14 - pH
pH = 8.69 is the pH at the equivalence point
Is nuclear fission exothermic or endothermic? Explain your answer.
Answer:
Exothermic
Explanation:
Nuclear fission means splitting, so there is a lot of energy being released.
Pls, Help ASAP with 30 points!!!
Describe the similarities and differences between the eruptions of
less gassy and more gassy magma.
Answer:
the difference is tyat eruptions of less gassy and more gassy is that the less gassy doesnt retain as much gas as the more gassy one and thus the eruption of the less gassy is less damage to the more gassy
27. A compound has a mass of 2.6632 10 2 g/mol. The number of significant figures in this mass
is —
A. 2
B. 4
C. 5
D. 7
Answer:
its b
B. 4
Explanation:
A plant uses carbon dioxide and water to form food and oxygen. Why is this a chemical change?
Answer:
The plant uses carbon dioxide and water to make an entirely new chemical hence chemical change.
Explanation:
Plants create their own 'food', they turn carbon dioxide water and sunlight to create starch and glucose..
Answer:
The properties of carbon dioxide and oxygen are different.
Explanation:
im taking the exam right now and Im pretty sure it's D The properties of carbon dioxide and oxygen are different.
which of the following determines an object’s ability to float in water?
a. how much the object weighs
b. what the mass of the object is
c. how dense the object is
d. the volume of the object
Two elements in the same period have the same number of _____ _____ in their electron clouds.
Answer:
outer electrons
Explanation:
Answer:
Energy levels
Explanation:
If a central atom of a molecule only has two electron domains, what is the bond angle associated with the molecule?
120o
180o
90o
109.5o
Answer:
I think it's C.90º
Explanation:
Answer:
180o
Explanation:
It is 180 degrees because the central atom is the atom in the middle of two electrons. Think about it like a straight line, a straight line is equal to 180 degrees. One electron connected to the central atom will be 90 degrees and if there's another electron, it will be 180 degrees.
Hope this helps:)
A block of lead weighs 11.3 grams. How many atoms of lead are in this sample?
• Use 6.022 x 1023 mol
for Avogadro's number.
Answer:
To get the number of atoms in this sample, we first need the number of moles of lead in 11.3 grams
Number of moles of Lead:
Molar mass of lead = 207 grams / mol
Number of moles = given mass / molar mass
Number of moles = 11.3 / 207
Number of moles = 0.05 moles
Number of atoms of lead in 11.3 gram sample:
Number of atoms = Number of moles * avogadro's number
Number of atoms = 0.05 * 6.022 * 10²³
Number of atoms = 5 * 10⁻² * 10²³ * 6.022
Number of atoms = 30.11 * 10²¹
11.3 g block of lead contains 3.29×10²² atoms
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.022×10²³ atoms. Thus,
1 mole of lead = 6.022×10²³ atoms
Recall:
1 mole of lead = 207 g
Thus,
207 g of lead = 6.022×10²³ atomsWith the above information in mind, we can obtain the number of atoms in 11.3 g block of lead as illustrated below:
207 g of lead = 6.022×10²³ atoms
Therefore,
11.3 g of lead = (11.3 × 6.022×10²³) / 207
11.3 g of lead = 3.29×10²² atomsThus, 11.3 g block of lead contains 3.29×10²² atoms
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Give the spectator ions for the reaction that occurs when aqueous solutions of H2SO4 and KOH are mixed.
a. OH- and K+
b. H+ and SO4-2
c. K+ and SO4-2
d. H+ and OH-
e. No spectator ions are present.
Answer:
Option C. K⁺(aq) and SO₄²¯(aq)
Explanation:
We'll begin by writing the ionic equation between H₂SO₄ and KOH.
This is illustrated below:
In solution, H₂SO₄ and KOH will dissociate as follow
H₂SO₄ (aq) —> 2H⁺ (aq) + SO₄²¯ (aq)
KOH (aq) —> K⁺ (aq) + OH¯ (aq)
Thus, aqueous H₂SO₄ and KOH will react as follow:
H₂SO₄ (aq) + 2KOH (aq) —> K₂SO₄ (aq) + 2H₂O (l)
Ionically:
2H⁺(aq) + SO₄²¯(aq) + 2K⁺(aq) + 2OH¯(aq) —> 2K⁺(aq) + SO₄²¯(aq) + 2H₂O (l)
The spectator ions are those ions that appear on both sides of the equation.
From the above ionic equation, the spectator ions are:
K⁺(aq) and SO₄²¯(aq)
PRACTICE PROBLEM Two compounds, A and B, have the same molecular formula, C6H8. Both A and B react with two molar equivalents of hydrogen in the presence of platinum to yield cyclohexane. Compound A shows three signals in its broadband decoupled NMR spectrum. Compound B shows only two NMR signals. Compound A shows an absorption maximum at 256 nm, whereas B shows no absorption maximum at wavelengths longer than 200 nm. What are the structures of A and B
Answer:
See explanation
Explanation:
One basic thing that we must keep in mind is that A and B are both dienes.
The NMR spectrum and absorption maxima of A and B indicates that A may be a conjugated diene while B may be an isolated diene.
Remember that conjugated dienes shift the absorption maxima to longer wavelengths due to π - π* transition.
The two structures attached may suffice for compounds A and B
Calculate the equilibrium concentration of H3O in the solution if the initial concentration of C6H5COOH is 0.056 M . Express your answer using two significant figures.
Answer:
1.9 × 10⁻³ M
Explanation:
Step 1: Write the acid ionization of benzoic acid
C₆H₅COOH(aq) + H₂O(l) ⇄ C₆H₅COO⁻(aq) + H₃O⁺(aq)
Step 2: Calculate the acid ionization constant (Ka) of benzoic acid
The pKa of benzoic acid is 4.20
pKa = -log Ka
Ka = antilog -pKa = antilog -4.20 = 6.31 × 10⁻⁵
Step 3: Calculate the equilibrium concentration of the hydronium ion
Considering that the initial concentration of the benzoic acid is Ca = 0.056 M, we can calculate the equilibrium concentration of the hydronium ion using the following expression.
[H₃O⁺] = √(Ca × Ka) = √(0.056 × 6.31 × 10⁻⁵) = 1.9 × 10⁻³ M
A dolphin can travel 30 miles in 2 hours. What is the dolphin's speed (Remembers = d+t)
Answer:
The dolphin's fast cruising speed (a travelling speed they can maintain for quite a while) is about 3-3.5 m/s (6-7 knots, 11-12.5 km/hr)
Explanation:
so 37 kilometers
A bomb calorimeter with a heat capacity of 837 J∘C contains 745 g of water. It burns 2.50 g C8H18 resulting in the temperature going from 15.0∘C to 33.8∘C. What is the value of the heat transferred (in kilojoules) by the reaction from the perspective of the system?
Answer:
74.3kJ are transeferred
Explanation:
In the bomb calorimeter, the burning of C₈H₁₈ is producing heat that is been absorbed for the calorimeter and the water.
Heat absorbed calorimeter:
837J/°C * (33.8°C-15.0°C) = 15735.6J
Heat absorbed water:
C*m*ΔT
C specific heat of water (4.184J/g°C), m is mass of water (745g), and ΔT change in temperature (33.8°C - 15°C = 18.8°C)
4.184J/g°C*745g*18.8°C = 58601.1J
Heat released by the reaction:
15735.6J + 58601.1J = 74336.7J
74.3kJ are transeferred
An aqueous solution of Pb(NO3)2 is made by placing 275 g of solid Pb(NO3)2 into a volumetric flask and adding water to the 1.00 L mark (assume that 775g of water has been added to achieve this total solution volume). (Assume MW of Pb(NO3)2 = 331g/mole) A) What is the molarity (M) of this solution? B) What is the molality (m) of this solution? C) What is the mass % of Pb(NO3)2 in this solution? D) What is the mole fraction of Pb(NO3)2 present in this solution?
Answer:
A) 0.831 M
B) 1.07 m
C) 26.2%
D) 0.0189
Explanation:
A) First we convert the mass of Pb(NO₃)₂ to moles:
275 g ÷ 331 g/mol = 0.831 mol Pb(NO₃)₂Then we divide it by the total volume (1.00 L) to calculate the molarity:
0.831 mol / 1.00 L = 0.831 MB) We convert the grams of water to kilograms:
775 g / 1000 = 0.775 kgThen we divide the Pb(NO₃)₂ by the kilograms of water:
0.831 mol / 0.775 kg = 1.07 mC) We divide the mass of Pb(NO₃)₂ by the total mass of the solution:
[tex]\frac{gPb(NO_{3})_{2}}{gPb(NO_{3})_{2}+gH_{2}O}[/tex] *100% [tex]=\frac{275}{275+775}[/tex] * 100% = 26.2%D) We calculate the moles of water:
775 g H₂O ÷ 18g/mol = 43.1 mol H₂OThen we divide the Pb(NO₃)₂ moles by the total number of moles:
[tex]\frac{0.831}{0.831+43.1}[/tex] = 0.0189I NEED HELP ASAP
1.Compare and contrast starch, cellulose, and glycogen. Include the monomers, function, and what type of organism they are found?
2. Describe the relationship between DNA and the structure of proteins. How might a change in the order of nucleotides result in a non-functional protein?
ANYTHING WILL HELP...WILL GIVE A BRAINLY
Answer:
the second on is, Changing the sequence of nucleotides in the DNA molecule can change the amino acids in the final protein, leading to protein malfunction. If insulin does not function correctly, it might be unable to bind to another protein (insulin receptor).
the first one is, These three polysaccharides differ in their glycosidic linkages and their functions too. Starting from the cellulose which is the monomer of beta glucose and is found in plant cell wall only. While Starch and Glycogen act as the carbohydrate reserve in plants and animals respectively. Though their chains have slight differences at the branching point, which is described below.
Explanation:
hope it helps
A sample of sodium bicarbonate is placed in an evacuated container at allowed to reach equilibrium. What will be the total pressure?
Complete Question
Sodium carbonate, Na2CO3(s), can be prepared by heating sodium bicarbonate, NaHCO3(s).
2NaHCO3(s) ------> Na2CO3(s) + CO2(g) + H2O(g) Kp = 0.23 at 100oC
If a sample of NaHCO3 is placed in an evacuated flask and allowed to achieve equilibrium at 100oC, what will the total gas pressure be?
Answer:
The value is [tex]P_T = 0.959 \ atm [/tex]
Explanation:
From the question we are told that
The equation is
[tex]2NaHCO_3_{(s)} \rightarrow Na_2CO_3_{(s)} + CO2_{(g)} + H2O_{(g)}[/tex]
Generally the equilibrium partial pressure is mathematically represented as
[tex]K_p = P_{CO_2} + P_{H_2O}[/tex]
Here
[tex] P_{CO_2} \ and \ P_{H_2O}[/tex] are partial pressures of [tex] CO_2 \ and \ H_2O [/tex] gases
Note: when writing the formula for equilibrium partial pressure we consider only the gas in the reaction
Let assume that
[tex]P_{CO_2} = a[/tex]
Generally [tex]P_{CO_2} = P_{H_2O}[/tex] since they are both products of the reaction
So
[tex]K_p = a^2 [/tex]
From the question we are told that [tex]K_p = 0.23 [/tex]
So
[tex] 0.23= a^2 [/tex]
=> [tex] a = \sqrt{0.23} [/tex]
=> [tex] a = \sqrt{0.23} [/tex]
=> [tex] a = 0.4796 \ atm [/tex]
So
[tex]P_{CO_2} = 0.4796 \ atm[/tex]
and
[tex]P_{H_2O} = 0.4796 \ atm [/tex]
So the total pressure is
[tex]P_T = 0.4796 + 0.4796[/tex]
=> [tex]P_T = 0.959 \ atm [/tex]
Convert 15.5 pounds to kilograms. Please and thank you so much!!
Answer:
7.030682 kg
hope it helps!
Answer:
7.030682
Explanation:
Wht is 30.00 grams of H3PO4
Answer:
0.31 mol
Explanation:
An increase in temperature results in A) a decrease in the required activation energy while the reaction rate remains constant. B) an increase in reaction rate due to a decrease in the kinetic energy of the reactants. C) an increase in the rate of reaction because reactant molecules collide with greater energy. D) an increase in both the reaction rate and activation energy due to increased kinetic energy.
Answer:
C) an increase in rate of reaction because reactant molecules collide with greater energy
Explanation:
Temperature is one of the factors that affect the rate of a reaction. The rate of a reaction increases with an increase in temperature and vice versa. When the temperature of a reaction increases, the kinetic energy of the reactant molecules increases causing them to react at a faster rate.
The reactant molecules respond to an increase in temperature by colliding at a faster rate due to an increased kinetic energy between the reactant molecules.
After heating the solution, you decant the liquid and wash the remaining solid with distilled water. What you are removing by this washing?
Answer:
The solvent
Explanation:
After the solid is recoverd by decanting the liquid, some solvent particles may still adhere to the solid.
In order to remove the solvent that may have adhered to the solid completely , the solid is washed before it is now dried.
In order to remove the remaining liquid present the solid material.
We are washing the solid in order to remove the liquid particles that is attached to the solid material with the help of water. Water is a universal solvent that dissolve large number of solutes in it.
Water removes the liquid from the solid by attaching with that liquid or dissolving in it so that's why we use water for washing a solid in order to remove the impurities from the solid material in which it is placed.
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The osmotic pressure exerted by a solution is equal to the molarity multiplied by the absolute temperature and the gas constant . Suppose the osmotic pressure of a certain solution is measured to be at an absolute temperature of . Write an equation that will let you calculate the molarity of this solution. Your equation should contain only symbols. Be sure you define each symbol other than . Your equation: Definitions of your symbols:
Answer:
c = π / R × T
Explanation:
The osmotic pressure exerted by a solution is equal to the molarity multiplied by the absolute temperature and the gas constant R . Suppose the osmotic pressure of a certain solution is measured to be 22 atm at an absolute temperature of 353 K. Write an equation that will let you calculate the molarity c of this solution. Your equation should contain only symbols. Be sure you define each symbol other than R.
Step 1: Given data and definition of the symbols
Osmotic pressure (π): 2.2 atmMolarity of the solution (c): ?Ideal gas constant (R): 0.08206 atm.L/mol.KAbsolute temperature (T): 353 KStep 2: Write an equation that will let you calculate the molarity of this solution, in terms of symbols
The osmotic pressure is a colligative property that can be calculated using the following expression.
π = c × R × T
We can rearrange this expression to calculate the molarity of the solution.
c = π / R × T
Which of the items below is a colloid?
a.fruit salad b.gelatin c.lacquer
Answer:
b. gelatin
Explanation:
a homogeneous noncrystalline consisting of large molecules or ultramicroscopic particles of one substance.
how light warms up matter
Answer:
Tom Zepf of the physics department at Creighton University in Omaha, Neb., notes that "Sunlight heats a material such as water or a brick primarily because the long wavelength, or infrared, portion of the sun's radiation resonates well with molecules in the material, thereby setting them into motion.
branliest pls?????/
Explanation:
