Answer:
0.168mL of the 1.0M KI solution must be added
Explanation:
The PbI₂ is in equilibrium with water as follows:
PbI₂ ⇄ Pb²⁺ + 2I⁻
Where Ksp is:
Ksp = 1.4x10⁻⁸ = [Pb²⁺] / [I⁻]²
As molarity of Pb²⁺ is 0.11M:
1.4x10⁻⁸ = [0.11M] / [I⁻]²
1.27x10⁻⁷ = [I⁻]²
3.57x10⁻⁴M = [I⁻]
Thus, to precipitate all Pb²⁺ you need to add 3,57x10⁻⁴M of I⁻. As volume of the solution is 470.0mL = 0.47L, you need to add:
0.47L * (3,57x10⁻⁴moles / L) = 1.68x10⁻⁴ moles of I⁻ = Moles of KI.
That comes from the 1.0M KI. You need to add:
1.68x10⁻⁴ moles of KI * (L / 1.0 mol) = 1.68x10⁻⁴L =
0.168mL of the 1.0M KI solution must be addedProspectors are considering searching for gold on a plot of land that contains 2.45 g of gold per bucket of soil. If the volume of the bucket is 5.25L, how many grams of gold are there likely to be in 1.0 cubic feet of soil
Answer:
13.2 g of gold
Explanation:
We'll begin by converting 5.25 L to ft³.
This can be obtained as follow:
Recall:
1 L = 0.0353 ft³
Therefore,
5.25 L = 5.25 × 0.0353
5.25 L = 1.85×10¯¹ ft³
From the question given above,
2.45 g of gold is present in 5.25 L ( i.e 1.85×10¯¹ ft³) of soil.
Therefore, Xg of gold will be present in 1 ft³ of soil i.e
Xg of gold = 2.45/1.85×10¯¹
Xg of gold = 13.2 g
Therefore, 13.2 g of gold is present in 1 ft³ of the soil.
why is the concentration of a solid left out of the equilibrium expression for the solubility of a salt
Answer:
Its concentration remains constant
Explanation:
The concentration of a pure solid is left out of the expression for the equilibrium solubility of a salt because the concentration of a pure solid remains constant. Therefore, the activity of a pure solid is 1.
Being of a constant concentration, the pure solid is not included in equilibrium expression for the solubility of a salt.
Which of the following factors has no effect on the rate of SN1 reactions?a. the nature of the alkyl halide. b. the nature of the leaving group c. the concentration of the alkyl halide d. the concentration of the nucleophile e. the value of the rate constant
Answer:
the concentration of the nucleophile
Explanation:
In an SN1 mechanism, the rate determining step is the formation of the carbocation. The nucleophile does not appear in the rate equation because the rate determining step is unimolecular and entirely depends on the concentration of the alkyl halide.
Hence, the concentration of the nucleophile has no effect on the rate of an SN1 reaction because the rate determining step involves only the alkyl halide.
The factor which has no effect on the rate of SN¹ reaction is the concentration of the nucleophile.
What is SN¹ reaction?SN¹ reaction is known as unimolecular nucleophilic reaction, which is completed in two steps.
First step in the SN¹ reaction is the rate determining step i.e. that step determines the rate of reaction. And in this step formation of carbocation takes place because of the loss of leaving group from the reactant. So, rate of reaction is not depends on the concentration of attacking nucleophile.
Hence, option (d) is correct.
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It is safest to heat the contents of test tubes in a flame while seated.
a) true
b) false
Answer:
False because the contaminents will get on your lap while having less time to react
Explanation:
Answer:
False
I hope this helps!
The atomic number of an atom is always equal to the total number of
neutrons in the nucleus
neutrons plus protons in the atom
protons in the nucleus
protons plus electrons in the atom
The amount of protons in the nucleus multiplied by the atomic number of an atom results in a constant value.
Why do protons exist?a fundamental unit of matter that shares the same structure as the hydrogen atom's nucleus, makes up all other atomic nuclei together with the neutron, has a mass of 1.673 1027 kilograms, and carries a positive charge that is numerically equal to the charge of an electron.
What materials make up protons?Two up quarks as well as a down quark combine to form protons. One up quark with two down quarks make up neutrons. The nucleus is kept together by one of the four basic forces known as the "strong nuclear force."
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Convert 0.00000000045 to scientific notation.
Answer:
4.5 multiplied by 10, to the -10th power.
[tex](4.5 \times 10 { - }^{10} )[/tex]
A sample of ammonia gas was allowed to come to equilibrium at 400 K. 2NH3(g) <---> N2(g) 3H2(g) At equilibrium, it was found that the concentration of H2 was 0.0551 M, the concentration of N2 was 0.0183 M, and the concentration of NH3 was 0.383 M. What is Kc for this equilibrium
Answer:
Kc for this equilibrium is 2.30*10⁻⁶
Explanation:
Equilibrium occurs when the rate of the forward reaction equals the rate of the reverse reaction and the concentrations of reactants and products are held constant.
Being:
aA + bB ⇔ cC + dD
the equilibrium constant Kc is defined as:
[tex]Kc=\frac{[C]^{c}*[D]^{d} }{[A]^{a} *[B]^{b} }[/tex]
In other words, the constant Kc is equal to the multiplication of the concentrations of the products raised to their stoichiometric coefficients by the multiplication of the concentrations of the reactants also raised to their stoichiometric coefficients. Kc is constant for a given temperature, that is to say that as the reaction temperature varies, its value varies.
In this case, being:
2 NH₃(g) ⇔ N₂(g) + 3 H₂(g)
the equilibrium constant Kc is:
[tex]Kc=\frac{[N_{2} ]*[H_{2} ]^{3} }{[NH_{3} ]^{2} }[/tex]
Being:
[N₂]= 0.0551 M[H₂]= 0.0183 M[NH₃]= 0.383 Mand replacing:
[tex]Kc=\frac{0.0551*0.0183^{3} }{0.383^{2} }[/tex]
you get:
Kc= 2.30*10⁻⁶
Kc for this equilibrium is 2.30*10⁻⁶
Consider a lithium nucleus, of charge +3q. Calculate the first three electron energies for an electron in a Li++ ion, using the Bohr model.
Answer:
[tex]\mathbf{E_1 = -40.8 \ eV}[/tex]
[tex]\mathbf{E_2= -10.2 \ eV}[/tex]
[tex]\mathbf{E_3=-4.533 \e V}[/tex]
Explanation:
In an hydrogen like atoms, the formula related to the energy of an nth quantum number is:
[tex]E_n =\dfrac{ -13.6 \times Z}{n^2}[/tex]
where;
lithium Z = 3
therefore, the energy levels for Li²⁺ are
n=1 , n=2, n= 3
[tex]E_1 =\dfrac{ -13.6 \times 3}{1^2}[/tex]
[tex]E_1 = -13.6 \times 3[/tex]
[tex]\mathbf{E_1 = -40.8 \ eV}[/tex]
[tex]E_2=\dfrac{ -13.6 \times 3}{2^2}[/tex]
[tex]E_2=\dfrac{ -13.6 \times 3}{4}[/tex]
[tex]\mathbf{E_2= -10.2 \ eV}[/tex]
[tex]E_3=\dfrac{ -13.6 \times 3}{3^2}[/tex]
[tex]E_3=\dfrac{ -13.6 \times 3}{9}[/tex]
[tex]\mathbf{E_3=-4.533 \e V}[/tex]
What is milk made of?
Answer:
Protein
Explanation:
Answer:
Water, fat, proteins, lactose, and minerals. Milk also contains trace amounts of other substances such as pigments, enzymes, vitamins, phospholipids, and gases.
What is the pH of a 0.1 M solution of acetic acid (pKa = 4.75)?
Answer:
[tex]pH=2.88[/tex]
Explanation:
Hello,
In this case, since dissociation of acetic acid is:
[tex]CH_3COOH\rightleftharpoons CH_3COO^-+H^+[/tex]
The equilibrium expression in terms of the acid dissociation constant is:
[tex]Ka=\frac{[CH_3COO^-][H^+]}{[CH_3COOH]}[/tex]
In such a way, in terms of the reaction extent, we write:
[tex]Ka=\frac{x*x}{0.1-x}[/tex]
And Ka is computed from the pKa:
[tex]Ka=10^{-pKa}=10^{-4.75}=1.78x10^{-5}[/tex]
[tex]1.78x10^{-5}=\frac{x*x}{0.1-x}[/tex]
Thus, solving for [tex]x[/tex] we obtain:
[tex]x=0.001325M[/tex]
Which is also equal to the concentration of H⁺ so the pH is:
[tex]pH=-log(0.001325)\\\\pH=2.88[/tex]
Regards.
What is the amount of matter in an object? O Kilograms O Mass O Volume O Weight
Answer:
Mass
Explanation:
Mass measures the amount of matter in a substance or an object. The basic SI unit for mass is the kilogram (kg). Volume measures the amount of space that a substance or an object takes up.
The amount of matter in an object is given in terms of it's mass.
What is the relation between mass and weight?
Mass is defined as the combination of physical properties of an object and the resistance which object undergoes when force is applied to it.It contains total number of protons,electrons and neutrons present in the atom of an object.
Mass does not change according to location but weight does change according to location as the amount of gravity varies from one location to another.Mass can be measured using any kind of balance but weight is measured by using spring balance only.
The SI unit of mass is kilograms.Weight is defined as force exerted on an object due to the gravitational force.Weight and mass are directly proportional to each other.Their relation is based on Newton's second law of motion .Formula of weight is
w=m×g
where, w=weight of object
m=mass of an object
g=gravity acting on the object
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4.0 g Mg and 4.0 g O2 are placed in a container and magnesium oxide, MgO, forms. The Mg is totally consumed but 1.4 g O2 remains. How much magnesium oxide formed
Answer:
The correct answer is: 6.6 g MgO
Explanation:
First we have to write and balance the chemical reaction as follows:
2Mg(s) + O₂(g) → 2MgO(s)
That means that 2 moles of Mg(s) react with 1 mol of O₂(g) to give 2 moles of MgO(s). If Mg is totally consumed and a mass of O₂ remains unaltered after reaction, the limiting reactant is Mg. We use the limiting reactant to calculate the mass of product.
According to the balanced chemical equation, 2 moles of Mg(s) produce 2 moles of MgO(s).
2 moles Mg = 2 mol x molar mas Mg= 2 mol x 24.3 g/mol = 48.6 g Mg
2 moles MgO= 2 mol x (molar mass Mg + molar mass O) = 2 mol x (24.3 g/mol + 16 g/mol) = 80.6 g MgO
The stoichiometric ratio is 80.6 g MgO/48.6 g Mg. So, we multiply this ratio by the mass of consumed Mg (4.0 g) in order to obtain the produced mass of MgO:
4.0 g Mg x 80.6 g MgO/48.6 g Mg = 6.63 g MgO
6.6 grams of magnesium oxide are formed.
In the reaction: CH 3COOH(aq) + NH 2 – (aq) CH 3COO – (aq) + NH 3(aq), the conjugate acid-base pairs are:
Answer: CH3COO- & CH3COOH are conjugate
NH2- & NH3 are conjugate
Explanation:
Which of the following equilibria would not be affected by pressure changes at constant temperature?
A) CO(g) + 1/2O2(g) CO2(g).
B) CaCO3(s) CaO(s) + CO2(g).
C) 2H2(g) + O2(g) 2H2O(l).
D) 2Hg(l) + O2(g) 2HgO(s).
E) CO2(g) + H2(g) CO(g) + H2O(g).
Answer:
Option A) CO(g) + 1/2O2(g) <=> CO2(g).
Explanation:
A background knowledge of reaction rates shows that pressure will only affect gaseous reactant.
Further more, we understood that for pressure to effectively affect gaseous molecules, the total volume of the gaseous reactant must be different from the total volume of the gaseous products.
Now, let us consider the equation given in the question:
A) CO(g) + 1/2O2(g) <=> CO2(g).
B) CaCO3(s) <=> CaO(s) + CO2(g).
C) 2H2(g) + O2(g) <=> 2H2O(l).
D) 2Hg(l) + O2(g) <=> 2HgO(s).
E) CO2(g) + H2(g) <=> CO(g) + H2O(g).
From the above, only option A and E has gaseous reactant and product.
For option A:
CO(g) + 1/2O2(g) <=> CO2(g).
Total volume of reactant = 1 + 1/2 = 3/2 L
Total volume of product = 1 L
Since the volume of the reactant and that of the product are different, therefore, a change in pressure will affect the reaction.
For option E:
CO2(g) + H2(g) <=> CO(g) + H2O(g).
Total volume of reactant = 1 + 1 = 2 L
Total volume of product = 1 + 1 = 2 L
Since the volume of the reactant and that of the product are the same, therefore, a change in pressure will have no effect in the reaction.
The equilibrium equation, CO2(g) + H2(g) ⇄ CO(g) + H2O(g), is not affected by pressure changes at constant temperature because there are equal volumes of reactants and products on both sides of reaction equation.
For a gas phase reaction, changes in pressure would affect the direction in which the reaction moves. When the pressure is increased, the reaction moves in the direction of lesser volumes. When the pressure is decreased, the reaction moves in the direction of greater volumes.
For the reaction; CO2(g) + H2(g) ⇄ CO(g) + H2O(g), there are equal volumes of reactants and products on either side of the reaction equation. Therefore, the equilibria would not be affected by pressure changes at constant temperature.
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What is the stoichiometric coefficient for oxygen when the following equation is balanced using the lowest whole-number coefficients? C3H6O2(l) + O2(g) → CO2(g) + H2O(l)A) 5 B) 7 C) 1 D) 3
Answer:
Option (B) 7
Explanation:
C3H6O2(l) + O2(g) → CO2(g) + H2O(l)
To know the coefficient of O2 in the above equation, let us balance the equation.
The above equation can be balance as follow:
C3H6O2(l) + O2(g) → CO2(g) + H2O(l)
There are 3 atoms of C on the left side and 1 atom on the right side. It can be balance by putting 3 in front of CO2 as shown below:
C3H6O2(l) + O2(g) → 3CO2(g) + H2O(l)
There are 6 atoms of H on the left side and 2 atoms on the right side. It can be balance by putting 3 in front of H2O as shown below:
C3H6O2(l) + O2(g) → 3CO2(g) + 3H2O(l)
There are a total of 4 atoms of O on the left side and a total of 9 atoms on the right side. It can be balance by putting 7/2 in front of O2 as show below:
C3H6O2(l) + 7/2O2(g) → 3CO2(g) + 3H2O(l)
Multiply through by 2
2C3H6O2(l) + 7O2(g) → 6CO2(g) + 6H2O(l)
Now, the equation is balanced.
From the balanced equation above, the coefficient of O2 is 7.
The normal boiling point of acetic acid is 118.1°C. If a sample of the acetic acid is at 125.2°C, predict the signs of ΔH, ΔS, and ΔG for the boiling process at this temperature
The question is incomplete, the complete question is;
The normal boiling point of acetic acid is 118.1°C. If a sample of the acetic acid is at 125.2°C, predict the signs of ∆H, ∆S, and ∆G for the boiling process at this temperature.
A. ∆H > 0, ∆S > 0, ∆G < 0
B. ∆H > 0, ∆S > 0, ∆G > 0
C. ∆H > 0, ∆S < 0, ∆G < 0
D. ∆H < 0, ∆S > 0, ∆G > 0
E. ∆H < 0, ∆S < 0, ∆G > 0
Answer:
A. ∆H > 0, ∆S > 0, ∆G < 0
Explanation:
During boiling, a liquid is converted to vapour. This is a phase change for which heat is absorbed because energy must be taken in to break the intermolecular bonds in the liquid before it can be converted to a gas. Hence ∆H>0
Secondly, a phase change from liquid to gas leads to an increase in entropy hence ∆S>0.
Thirdly, the process is spontaneous. For every spontaneous process ∆G<0
Water flows over Niagara Falls at the average rate of 2,400,000 kg/s, and the average height of the falls is about 50 m. Knowing that the gravitational potential energy of falling water per second = mass (kg) × height (m) × gravity (9.8 m/s2), what is the power of Niagara Falls? How many 15 W LED light bulbs could it power?
Answer:
Power, [tex]P=1.176\times 10^9\ W[/tex]
No of bulbs = 78400000
Explanation:
We have,
Water flows over Niagara Falls at the average rate of 2,400,000 kg/s, it mean it is mass per unit time i.e. m/t.
It falls from a height of 50 m
The gravitational potential energy of falling water is given by :
P = mgh
Power is equal to the work done divided by time taken. So,
[tex]P=\dfrac{W}{t}\\\\P=\dfrac{mgh}{t}\\\\P=\dfrac{m}{t}\times gh[/tex]
So,
[tex]P=2400000\times 9.8\times 50\\\\P=1.176\times 10^9\ W[/tex]
Let there are n bulbs that could power 15 W LED. It can be calculated by dividing the power by 15. So,
[tex]n=\dfrac{1.176\times 10^9}{15}\\\\n=78400000\ \text{bulbs}[/tex]
It means that the number of bulbs are 78400000.
Write the formulas for: Ca and CI, Na and CI, H and 0, Al and 0, and K and F.
Answer:
Below
Explanation:
Combination of Calcium(Ca) and Chlorine(Cl); Calcium chloride
[tex]Ca+Cl_2 -> CaCl_2[/tex]
Combination of Sodium(Na) and Chlorine(Cl); Sodium chloride(salt)
[tex]Na+Cl_2 -> NaCl[/tex]
Combination of Hydrogen(H) and Oxygen(O);(water)
[tex]H_2 +O_2-> H_2O[/tex]
Combination of Potassium (K) and Fluorine(f) ; Potassium fluoride
[tex]K+F ->KF[/tex]
In which of the following groups of substances would dispersion forces be the only significant factors in determining boiling points? I. Cl2 II. HF III. Ne IV. KNO2 V. CCl4
Answer:
Cl2,Ne, CCl4
Explanation:
Dispersion forces are quite significant as the predominant intermolecular forces in nonpolar substances. For Cl2,Ne and CCl4, dispersion forces are the primary kind of intermolecular interaction present in the compound.
Hence, the boiling point of these substances will be determined solely by the dispersion forces between the molecules.
Cl2, Ne, CCl4 are the group of substances in which dispersion forces would
help determine the boiling point.
Dispersion force is a type of Van der waals force and is also regarded as
London forces. This type of force occur between the atoms and molecules
when electrons are symmetrically distributed in the nucleus.
This force is a weak intermolecular force and is present in non polar
compounds such as Cl2, Ne, CCl4 . KNO2 is polar and hence doesn't
determine its boiling point.
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Using the balanced equation below,
how many grams of carbon dioxide
would be produced from the
complete reaction of 83.7 g carbon
monoxide?
Fe2O3 + 3CO → 2Fe + 3CO2
Answer:131.6 g
Explanation:
131.6 grams of carbon dioxide would be produced from the complete reaction of 83.7 g carbon monoxide.
The balanced chemical equation is given below.
Fe2O3 + 3CO → 2Fe + 3CO2
Calculation,
Since, 28g of carbon dioxide produces 44g of carbon monoxide.
So, 83.7 g of carbon dioxide produces 44×83.7/28 grams
83.7 g of carbon dioxide produces 131.6 grams
What is chemical equation?The symbolic representation of chemical reaction in which reactant represents in left side and product represents in right side is called chemical equation.
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Which of the following discovery led mankind to observe changes in certain rocks and minerals which further led to the development of ceramics, glass, and metals?
a. Plasma
b. Plastic
c. Fire
d. Neoprene
e. Rubber
Answer:
A
Explanation:
Identify the missing nuclide in the following nuclear equation:
214 Pb → 0 e + ?
82 -1
A. Pb-215.
B. Bi-214.
C. Pb-213.
D. TI-215.
E. TI-214.
Answer:
B. Bi-214.
Explanation:
The equation shows beta particle emission of 214/82 Pb which result into 214/83 Bi, in which the mass remain same but the the atomic number increases by one.
During this emission neutron get split into an electron and a proton which are represented as 0/e/-1.
So, the final nuclear equation becomes : 214/82 Pb => 0 e -1 + 214/83 Bi
Hence, the correct answer is "B. Bi-214."
Identify the predominant intermolecular forces in each of these substances.
1. H2O
2. CaCl2
3. CH3CH(CH3)OH
4. CH4
5. NH3
Answer:
H2O- hydrogen bonding
CaCl2- ion-ion interaction
CH3CH(CH3)OH- hydrogen bonding
CH4- dispersion forces
NH3- hydrogen bonding
Explanation:
Intermolecular forces are secondary bond forces that hold the molecules of a substance together in a given state of matter.
Intermolecular forces account for quite a number of the observed physical properties of a substance such as the boiling and melting point.
If a compound contains hydrogen atom bonded to a highly electronegative element, hydrogen bonding becomes the most dominant intermolecular force, e.g in water and ammonia.
For nonpolar molecules, dispersion forces are the most dominant intermolecular forces. In ionic substance, ion-ion interaction becomes quite prominent.
g the __ of the partial pressures of each gas in a mixture must equal the total pressure of the enntire gas mixture
Answer:
Sum.
Explanation:
Hello,
In this case, the Dalton's law states that the SUM of the partial pressures of each gas in a mixture must equal the total pressure of the entire gas mixture, considering its mathematical definition for a i-containing gas mixture:
[tex]P_t=P_1+P_2+...+P_i[/tex]
Regards.
In 1.00 mol of potassium zirconium sulfate trihydrate, K4Zr(SO4)4.3 H20, there are
A
3 x 6.02 x 10 hydrogen atoms
23
B
6.02 x 1023 sulfur atoms
с
4* 6.02 x 1023 potassium atoms
D
4 moles of oxygen atoms
E
4 moles of zirconium atoms
Answer:
C. 4 × 6.02 × 10²³ potassium atoms.
Explanation:
In 1.00 mol of potassium zirconium sulfate trihydrate, K₄Zr(SO₄)₄.3 H₂O, there are
A . 3 × 6.02 × 10²³ hydrogen atoms. NO. There are 3 × 2 moles of hydrogen atoms = 6 moles of hydrogen atoms = 6 × 6.02 x 10²³ hydrogen atoms
B. 6.02 × 10²³ sulfur atoms. NO. There are 4 moles of sulfur atoms = 4 × 6.02 × 10²³ sulfur atoms
C. 4 × 6.02 × 10²³ potassium atoms. YES. There are 4 moles of potassium atoms = 4 × 6.02 × 10²³ potassium atoms
D . 4 moles of oxygen atoms. NO. There are 4 × 4 moles of oxygen atoms = 16 moles of oxygen atoms
E . 4 moles of zirconium atoms NO. There is 1 mole of zirconium atoms
Question 4 of 10
Which question asks for an opinion?
A. How much electricity does the average nuclear power plant
generate?
B. Should the government invest more money in nuclear energy than
in solar energy?
C. What are the by-products generated by the manufacture of solar
panels?
D. How efficient is the most advanced solar energy technology?
Answer:
Should the government invest more money in nuclear energy than
in solar energy
Explanation:
This is because some people might think government should invest in nuclear energy while others might want the government to invest in solar energy.
Answer:
B. "Should the government..."; the answer to this relies on subjective input (what the audience thinks the government should do).
Explanation:
Think about the differences between statements that are subjective and objective. If you look at A, C, or D, these results of these experiments are all objective:
A) The amount of electricity generated by a power plant isn't "arguable"; it's a definite value that I can't just "make up" or "think" is correct/valid.
C) The byproducts generated by manufacture aren't "arguable" either; if a byproduct is heat, there's no subjective input.
D) Try to use the above reasoning for D!
Draw the structure of a molecule which contains only carbon and hydrogen atoms (only three of which are carbon) and in which two of the carbons are sp2 hybridized and the other is sp hybridized.
Answer:
CH₂ = C = CH₂
Explanation:
Hybridization is the mixing and blending of two or more pure atomic orbitals (s, p and d) to form two or more hybrid atomic orbitals that are identical in shape and energy e.d sp, sp², sp³, sp³d, sp³d² etc.
The structure of the organic molecule that contains only carbon and hydrogen atoms where there exist only three of which are carbon and in which two of the carbons are sp2 hybridized and the other is sp hybridized can be seen below.
CH₂ = C = CH₂ ( where the = sign represent the double bonds)
Here, The two carbons that are sp₂ hybridized are CH₂
the other carbon that is sp hybdrized is C
From this value, and assuming that air contains only molecular nitrogen and molecular oxygen gases, calculate the mass percent of N2 and of O2 in air.
Answer:
60% and 52%
Explanation:
At Standard temperature and volume (STP)
Volume of gas = 22.4L
Density = mass/volume
⇒ 1.186 = [tex]\frac{mass}{22.4}[/tex]
= 26.566g
Molar mass of O2 = 16g/mole
Molar mass of N2 = 14g/mol
% mass of O2 = 16/26.566 × 100
= 60.23 %
% mass of N2 = 14/26.566 × 100
= 52.70 %
(Check: totl composition of gas is 100% i.e 60 + 52 %)
1. Which of the following is a valid piece of scientific evidence?
a. The amount of snow pack in the mountains
b. The way a piece of music makes you feel
C. How many people like brownies more than cake
d. The color blue being called a calming color
Answer: A
Explanation: The other options are opinions and can vary in the way that people respond
The valid piece of scientific evidence among the options provided is:
a. The amount of snow pack in the mountains
Scientific evidence refers to observations or data that can be objectively measured, tested, and analyzed. The amount of snow pack in the mountains can be quantitatively measured and observed, making it a valid piece of scientific evidence. It can be used to study climate patterns, water availability, and various other scientific phenomena related to snow and mountain ecosystems.
The other options, b. The way a piece of music makes you feel, c. How many people like brownies more than cake, and d. The color blue being called a calming color, involve subjective experiences, personal preferences, and cultural associations rather than empirical observations that can be tested and measured in a scientific context.
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When looking at the equilibrium between silver bromide and its aqueous ions, what could be added to solution to promote precipitation of silver bromide?
Answer:
NaBr
Explanation:
When AgBr is dissolved in water, the following equilibrium is set up in solution;
AgBr(s)⇄Ag^+(aq) + Br^- (aq)
If we dissolve NaBr in the water, a common ion (Br^-) is now introduced into the system. This increases the concentration of Br^- and favours the reverse reaction hence more AgBr is precipitated. This is known as common ion effect.