Answer:
the number is 7
Explanation:
"Three times" means multiply by 3
"Difference" means subtract
"Sum" means add
3(x - 7) = 23 - (3x + 2)
3x - 21 = 23 - 3x - 2
3x - 21 = 21 - 3x
6x = 42
x = 7
An SN2 reaction is a type of _____________ in which the nucleophile attacks the electrophile.
Answer:
A bimolecular nucleophilic substitution (SN2) reaction is a type of nucleophilic substitution whereby a lone pair of electrons on a nucleophile attacks an electron deficient electrophilic center and bonds to it, resulting in the expulsion of a leaving group.
Indicate the peptides that would result from cleavage by the indicated reagent: a. Gly-Lys-Leu-Ala-Cys-Arg-Ala-Phe by trypsin b. Glu-Ala-Phe-Gly-Ala-Tyr by chymotrypsin
Answer:
a. Gly-Lys + Leu-Ala-Cys-Arg + Ala-Phe
b. Glu-Ala-Phe + Gly-Ala-Tyr
Explanation:
In this case, we have to remember which peptidic bonds can break each protease:
-) Trypsin
It breaks selectively the peptidic bond in the carbonyl group of lysine or arginine.
-) Chymotrypsin
It breaks selectively the peptidic bond in the carbonyl group of phenylalanine, tryptophan, or tyrosine.
With this in mind in "peptide a", the peptidic bonds that would be broken are the ones in the "Lis" and "Arg" (See figure 1).
In "peptide b", the peptidic bond that would be broken is the one in the "Phe" (See figure 2). The second amino acid that can be broken is tyrosine, but this amino acid is placed in the C terminal spot, therefore will not be involved in the hydrolysis.
Which of these species would you expect to have the lowest standard entropy (S°)?
a. CH4(g)
b. H2O(g)
c. NH3(g)
d. HF(g)
Answer:
d. HF(g)
Explanation:
Hello,
In this case, the standard entropy S° could be predicted by looking at the amount of bonds the compound has, thus, the fewer the number bonds, the lower the standard entropy, it means that d. HF(g) has lowest value as it has one bond only whereas methane has four bonds, water two bonds and ammonia three bonds.
Best regards.
What was one important discovery that the Curies made?
O A material's radioactivity cannot be changed by altering the material physically
O A material's radioactivity can be weakened or intensified by changing it chemically.
O Radioactive materials generally contain radium or polonium.
O Radioactive materials are found only in the form of salts.
Answer:
C is the answer to your question
Sean plated an unknown metal onto his silver ring which initially weighed 1.4 g. He constructs an electrolytic cell using his ring as one of the electrodes. After running the cell, 0.022 moles of the unknown metal was plated onto his ring and the mass of the ring increased to 3.137 g. What is the atomic weight of the unknown metal in g/mol
Answer:
79 g/mol
Explanation:
Mass of unknown metal deposited = 3.137 g - 1.4 g = 1.737 g
Number of moles of metal deposited = 0.022 moles
Since;
Number of moles = reacting mass/molar mass
Molar mass = reacting mass/number of moles
Molar mass = 1.737 g/0.022 moles
Molar mass= 79 g/mol
Which of the following buffer systems would be the best choice to create a buffer with pH 9.10?
a) HF/KF (pKa = 3.14)
HNO2/KNO2 (pKa = 3.39)
NH3/NH4Cl (pKa = 9.25)
HClO/KClO (pKa = 7.46)
b) for the best buffer system, calculate the ratio of the molarities of the buffer components required to make the buffer
c) for the best buffer system, calculate the ratio of the masses of the buffer components required to make 1.00 L of the buffer
Answer:
a) NH3/NH4Cl (pKa = 9.25)
b) [tex]\frac{[Base]}{[Acid]} =0.708[/tex]
c)
Explanation:
Hello,
a) In this case, for a buffering capacity, if we want to select the best buffer, we should ensure that the buffer's pKa approaches the desired pH, therefore, since the buffer NH3/NH4Cl has a pKa of 9.25 that is very close to the desired pH of 9.10, we can pick it as the best choice.
b) In this case, we use the Henderson-Hasselbach equation in order to compute the molar ratio:
[tex]pH=pKa+log(\frac{[Base]}{[Acid]} )\\\\log(\frac{[Base]}{[Acid]} )=9.10-9.25=-0.15\\\\\frac{[Base]}{[Acid]} =10^{-0.15}\\\\\frac{[Base]}{[Acid]} =0.708[/tex]
c) Finally, for the ratio of masses, we use the molar mass of both ammonia as the base (17 g/mol) and ammonium chloride as the acid (53.45 g/mol) to compute it, assuming 1.00 L as the volume of the solution:
[tex]\frac{m_{Base}}{m_{Acid}} =0.708\frac{molBase}{molAcid}*\frac{17gBase}{1molBase} *\frac{1molAcid}{53.45gAcid}\\ \\\frac{m_{Base}}{m_{Acid}} =0.225[/tex]
Regards.
The best choice to create a buffer with pH 9.10 is NH₃/NH₄Cl (pKa=9.25), ratio of molarities and masses for NH₃/NH₄Cl are 0.708 & 0.225 respectively.
How do we calculate the pH of buffer solution?pH of buffer solution will be calculated by using the Henderson Hasselbalch equation as:
pH = pKa + log([base]/[acid])
From the above reaction it is clear that valu of pH is directly proportional to the value of pKa. So, the pKa value for NH₃/NH₄Cl is comparatively high which will close to the 9.10 pH.Ratio of the molarities for the NH₃/NH₄Cl buffer solution will be calculated by using the Henderson Hasselbalch equation as:log([NH₃]/[NH₄Cl]) = 9.10 - 9.25 =
log([NH₃]/[NH₄Cl]) = -0.15
[NH₃]/[NH₄Cl] = [tex]10^{-0.15}[/tex] = 0.708
Ratio of masses for the NH₃/NH₄Cl buffer solution will be calculated by using the below equation as:M = n/V, where
M = molarity
V = volume = 1L
n = moles = W(mass) / M(molar mass)
Mass(NH₃)/Mass(NH₄Cl) = 0.708 {(mol of NH₃×17g of NH₃NH₃) /
(mol of NH₄Cl×53.45g of NH₄Cl)
Mass(NH₃)/Mass(NH₄Cl) = 0.225
Hence required values are calculated above.
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A skydiver slows down from 65 m/s to 5 m/s by opening the parachute. If this
takes 0.75 seconds, what is the skydiver's acceleration?
A. 45 m/s2 up
B. 80 m/s2 up
C. 45 m/s2 down
D. 80 m/s2 down
Answer:
D. -80m/s^2
Explanation:
V = u + at
5 = 65 + a (0.75)
0.75a = -60
a = -60/0.75
a = -80m/s^2
Therefore, is decelerating at 80m/s^2
Answer:
[tex]\boxed {\boxed {\sf D. \ 80 \ m/s^2 \ down}}[/tex]
Explanation:
We are asked to find the acceleration of a skydiver. Acceleration is the change in velocity over the change in time, so the formula for calculating acceleration is:
[tex]a= \frac{v_f-v_i}{t}[/tex]
The skydiver was initially traveling 65 meters per second, then he slowed down to a final velocity of 5 meters per second. He slowed down in 0.75 seconds.
[tex]\bullet \ v_f = 5 \ m/s \\\bullet \ v_i= 65 \ m/s \\\bullet \ t= 0.75 \ s[/tex]
Substitute the values into the formula.
[tex]a= \frac{ 5 \ m/s - 65 \ m/s}{0.75 \ s}[/tex]
Solve the numerator.
[tex]a= \frac{-60 \ m/s}{0.75 \ s}[/tex]
Divide.
[tex]a= -80 \ m/s^2[/tex]
The acceleration of the skydiver is -80 meters per second squared or 80 meters per second squared down. The skydiver is slowing down or decelerating, so the acceleration is negative or down.
When 0.100 M NaOH is titrated with 25.00 mL 0.0500 M HBr, which of the following is correct for this titration?
A. Initially the pH will be less than 1.00.
B. The pH at the equivalence point will be 7.00.
C. It will require 12.50 mL of NaOH to reach the equivalence point.
When 0.100 M NaOH is titrated with 25.00 mL 0.0500 M HBr, which of the following is correct for this titration?
A. Initially the pH will be less than 1.00.
B. The pH at the equivalence point will be 7.00.
C. It will require 12.50 mL of NaOH to reach the equivalence point.
a)A, C
b) A, B
c) B, C
d) B
Answer:
c) B, C
Explanation:
NaOH(aq) + HBr(aq) -----> NaBr(aq) +H2O(l)
1) concentration of acid CA= 0.05 M
Concentration of base CB= 0.1 M
Volume of acid VA= 25.00ml
Volume of base VB= unknown
Number of moles of acid NA= 1
Number of moles of base NB= 1
CAVA/CBVB = NA/NB
CAVANB =CBVBNA
VB= CAVANB/CB NB
VB= 0.05 × 25 × 1/ 0.1 ×1
VB= 12.5 ML
2.
How many atoms of oxygen are in one molecule of water (H2O)? one two four three
Answer:
there is one atom of oxygen and two atoms of hydrogen
Explanation:
An unknown compound has the following chemical formula:
Co(OH),
where x stands for a whole number.
Measurements also show that a certain sample of the unknown compound contains 5.1 mol of oxygen and 2.59 mol of cobalt.
Write the complete chemical formula for the unknown compound.
since we are given the moles for Co and O, we'll divide both of those moles by the lowest mole quantity, which is, in this case, 2.59. After dividing, we see that the ratio of O to Co is 2:1. So, for every 1 Co atom, there has to be 2 O atoms. we can then insert the 2 in for OH to satisfy this ratio.
g Solution of barium hydroxide reacts with phosphoric acid to produce barium phosphate precipitate and water. How many mL of 6.50 M calcium hydroxide solution are required to react with a phosphoric acid solution of 45.00 mL that has a concentration of 8.70 M protons (hydrogen ions)
Answer:
30.12 mL.
Explanation:
We'll begin by calculating the molarity of the phosphoric acid. This can be obtained as follow:
Phosphoric acid H3PO4 will dissociate in water as follow:
H3PO4(aq) <==> 3H^2+(aq) + PO4^3-(aq)
From the balanced equation above,
1 mole of H3PO4 produces 3 moles of H+.
Therefore, XM H3PO4 will produce 8.70 M H+ i.e
XM H3PO4 = 8.70/3
XM H3PO4 = 2.9 M.
Therefore, the molarity of the acid solution, H3PO4 is 2.9 M.
Next, we shall write the balanced equation for the reaction. This is illustrated below:
2H3PO4 + 3Ba(OH)2 —> Ba3(PO4)2 + 6H2O
From the balanced equation above, we obtained the following:
Mole ratio of the acid, H3PO4 (nA) = 2
Mole ratio of the base, Ba(OH)2 (nB) = 3
Data obtained from the question include the following:
Molarity of base, Ba(OH)2 (Mb) = 6.50 M
Volume of base, Ba(OH)2 (Vb) =.?
Molarity of acid, H3PO4 (Ma) = 2.9 M
Volume of acid, H3PO4 (Va) = 45 mL
The volume of the base, Ba(OH)2 Needed for the reaction can be obtained as follow:
MaVa /MbVb = nA/nB
2.9 x 45 / 6.5 x Vb = 2/3
Cross multiply
2 x 6.5 x Vb = 2.9 x 45 x 3
Divide both side by 2 x 6.5
Vb = (2.9 x 45 x 3) /(2 x 6.5)
Vb = 30.12 mL
Therefore, the volume of the base, Ba(OH)2 needed for the reaction is 30.12 mL
What is the rate constant of a reaction if rate = 1 x 10-2 (mol/L)/s, [A] is 2 M,
[B] is 3 M, m = 2, and n = 1?
Answer:
[tex]0.10 \text{ L$^2$mol$^{-2}$s$^{-1}$}[/tex]
Explanation:
The general formula for a rate law is
[tex]\text{rate} = k\text{[A]}^m \text{[B]}^{n}[/tex]
With your numbers, the rate law becomes
1.2 mol·L⁻¹s⁻¹ = k(2 mol·L⁻¹)²(3 mol·L⁻¹)¹ = k × 4 mol²L⁻² × 3 mol·L⁻¹
= 12k mol³L⁻³
[tex]\\ k = \dfrac{\text{1.2 mol $\cdot$ L$^{-1}$s$^{-1}$} }{12\text{ mol$^{3}$L}^{-3}} = \mathbf{0.10} \textbf{ L$\mathbf{^2}$mol$^{\mathbf{-2}}$s$^{\mathbf{-1}}$}[/tex]
1. What happens to global temperature averages that start an ice age?
Answer:
Around 46° F (7.8° C)
Explanation:
"Scientists have predicted that the global average temperature during the ice age was around 46 degrees Farenheit (7.8 degrees Celsius.) However, the polar regions were far colder, around 25 degrees Fahrenheit (14 degrees Celsius) colder than the global average."
Source: http://www.weforum.org
What is the concentration of A after 50.7 minutes for the second order reaction A → Products when the initial concentration of A is 0.250 M? (k = 0.117 M⁻¹min⁻¹)
Answer:
0.101 M
Explanation:
Step 1: Given data
Initial concentration of A ([A]₀): 0.250 MFinal concentration of A ([A]): ?Time (t): 50.7 minRate constant (k): 0.117 M⁻¹.min⁻¹Step 2: Calculate [A]
For a second-order reaction, we can calculate [A] using the following expression.
1/[A] = 1/[A]₀ + k × t
1/[A] = 1/0.250 M + 0.117 M⁻¹.min⁻¹ × 50.7 min
[A] = 0.101 M
Atoms are indivisible spheres. 1.plum pudding model 2.Dalton model 3.Bohr model
Answer: 2. Dalton Model
Explanation:
John Dalton proposed that atoms are indivisible spheres. Although his model of an atom was not entirely new to the scientific world since the ancient Greeks has made a similar statement in the past ( all matter are made up of small indivisible particle called atom).
As of when Dalton proposed his model of an atom, electrons and nucleus where yet to be discovered.
Describe the factors influencing chemical bonds and the
characteristics of an ionic and a covalent bond.
Explanation:
factors affecting chemical bonds
a. electronegativity difference
b. size
c. charges
characteristics of Ionic bond
a. high melting point
b. they are soluble in polar solvents
c. they don't conduct electricity in solid state
characteristics of covalent bonds
a. they are insoluble in polar solvents
b. they don't conduct electricity
c. low melting point
A compound is found to contain 31.42 % sulfur, 31.35 % oxygen, and 37.23 % fluorine by weight. To answer the questions, enter the elements in the order presented above. 1. What is the empirical formula for this compound? 2. The molecular weight for this compound is 102.1 g/mol. What is the molecular formula for this compound?
Explanation:
To obtain the empirical and molecular formula of this compound from the percent composition of the elements, we follow the steps below;
Step 1: Divide the percentage composition by the atomic mass
Sulphur = 31.42 / 32 = 0.9819
Oxygen = 31.35 / 16 = 1.9594
Flourine = 37.23 / 19 = 1.9595
Step 2: Divide by the lowest number
Sulphur = 0.9819 / 0.9819 = 1
Oxygen = 1.9594 / 0.9819 ≈ 2
Flourine = 1.9595 / 0.9819 ≈ 2
This means the ratio of the elements is 1 : 2: 2
The empirical formular (simplest formular of a compound) of the compound is;
SO₂F₂
To obtain the molecular formular (Actual formular of a compound);
(SO₂F₂)n = 102.1
Inserting the atomic masses and solving for n;
(102)n = 102.1
n ≈ 1
The molecular formular is; (SO₂F₂)₁ = SO₂F₂
clacium hydroxide is slightly soluable in water about 1 gram will dissolve in 1 liter what are the spectator ions in the reaction ions in the reaction of such a dilute solution of calcium hydroxide with hydrochloric acid
Answer:
Ca²⁺ and Cl⁻
Explanation:
In a chemical reaction, spectator ions are ions that are not involved in the reaction, that means are the same before and after the reaction.
In water, calcium hydroxide, Ca(OH)₂ is dissociated in Ca²⁺ and OH⁻. Also, hydrochloric acid, HCl, dissociates in H⁺ and Cl⁻. The reaction is:
Ca²⁺ + 2OH⁻ + 2H⁺ + 2Cl⁻ → 2H₂O + Ca²⁺ + 2Cl⁻
The ions that react are H⁺ and OH⁻ (Acid and base producing water)
And the ions that are not reacting, spectator ions, are:
Ca²⁺ and Cl⁻Im really confused and select all that apply questions scare me.
Answer:
The 3rd one
Explanation:
A critical reaction in the production of energy to do work or drive chemical reactions in biological systems is the hydrolysis of adenosine triphosphate, ATP, to adenosine diphosphate, ADP, as described by the reaction
ATP(aq)+H2O(l)→ADP(aq)+HPO2−4(aq) for which ΔGrxn=30.5 kJ/mol at 37.0∘C and pH 7.0.
Required:
Calculate the value of ΔGrxn in a biological cell in which [ATP]=5.0 mM, [ADP]=0.60 mM, and [HPO2−4]=5.0 mM
Answer:
ΔG = -49.64 KJ/mol
Explanation:
The actual free energy change of the reaction under the given conditions, ΔG is given by the formula below;
ΔG = ΔG'° + RT ln([ADP][HPO₂⁴⁻] / [ATP])
where ΔG'° = -30.5 KJ/mol; R = 8.315 J/mol.K; T = 37°C = 310 K; [ADP] = 5.0 mM = 0.005 M; [HPO₂⁴⁻] = 0.60 mM = 0.0006 M; [ATP] = 5.0 mM = 0.005 M
ΔG = -30.5 KJ/mol + (8.315 J/mol.K)(310 K) ln {(0.005)(0.0006)/(0.005)}
ΔG = -30.5 KJ/mol + (2.58 KJ/mol * -7.4186)
ΔG = -30.5 KJ/mol - 19.14 KJ/mol
ΔG = -49.64 KJ/mol
The valves in the heart open and close to move blood in between heart chambers. O a) three directions O b) two directions O c) four directions d) one direction
Answer:
im not sure but i think its four directions
Hi,
The valves in the heart open and close to move blood in between heart chambers.
Answer:
d) one direction
Identify a homogeneous catalyst. Identify a homogeneous catalyst. Pd in H2 gas N2 and H2 catalyzed by Fe SO2 over vanadium (V) oxide Pt with methane H2SO4 with concentrated HCl
Answer:
H2SO4 with concentrated HCl
3. Write the following isotope in hyphenated form (e.g., "carbon-14”): Kr
a. Krypton-109
b. Krypton -37
c. Krypton -36
d. Krypton -73
Answer:
Krypton -73
Explanation:
There are 33 known isotopes of krypton (36Kr) with atomic mass numbers from 69 through 101.
Good luck!
Answer:
D. Krypton-73
Explanation:
An isotope of an element has the same atomic number and the same number of protons but a different number of neutrons and a different atomic weight. Krypton is the 36th element on the periodic table. It has 36 protons and 48 neutrons. Krypton-73 is one of 33 known isotopes of Krypton and is the only one that actually exists from the list of choices.
Hope that helps.
Calculate the molarity of bromide ions in 250. mL of a solution containing 25.9 g NaBr and 0.155 moles of HBr.
Answer:
[tex]1.628 M[/tex]
Explanation:
From the question we were given 0.155 moles of HBr, but Br and H are in ratio 1:1, then there are 0.155 moles of Br- ions.
We were also told that the solution contain NaBr, of 25.9 g. Then it must be converted to moles.
molar mass of NaBr =(22.99g + 79.90 )
= 102.89 g per mol.
the moles of NaBr can be calculated as 25.9 / 102.89
=0.252 moles
But Na and Br are in a ratio 1:1 , then there are 0.252 moles of Br-.
Then to get two Br- mol , we will add the first and second mol of Br- together
= 0.155 + 0.252
=0.407 moles.
The given solution has volume of 250 mL, but we know that there are 1000 ml in a liter, then if we convert to L for unit consistency we have
= 250/1000
= 0.25 L
molarity=0.407 moles/0.25 L
= 1.628 M.
Therefore, Br ion molarity is 1.628 M.
The molarity of the Br ions in the 250 ml solution has been 1.628 M.
Moles can be defined as the mass per unit molecular mass. Moles can be expressed as:
Moles = [tex]\rm \dfrac{weight}{molecular\;weight}[/tex]
Moles of NaBr = [tex]\rm \dfrac{25.9}{102.89}[/tex]
Moles of NaBr = 0.252 mol
Moles of HBr = 0.155 mol.
Since both the compounds have 1:1 ratio of atom: Br, the Br produced has been equal to the concentration of the compound.
Br from NaBr = 0.252 mol
Br from HBr = 0.155 mol.
Total Br ions = 0.407 mol.
Molarity can be expressed as:
Molarity = [tex]\rm moles\;\times\;\dfrac{1000}{Volume\;(ml)}[/tex]
Molarity of Br ions = 0.407 × [tex]\rm \dfrac{1000}{250\;ml}[/tex]
Molarity of Br ions = 1.628 M.
The molarity of the Br ions in the 250 ml solution has been 1.628 M.
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What is the molarity of 4 g of NaCl dissolved in 100mL of water?
Answer:
[tex]M=0.684M[/tex]
Explanation:
Hello,
In this case, considering that the solution is formed by NaCl as the solute and water as the solvent, we can compute the molarity as shown below:
[tex]M=\frac{mol_{solute}}{V_{solution}}[/tex]
Whereas the volume of the solution must be in liters. In such a way, since the addition of sodium chloride does not significantly changes the volume of the solution we can say it remains in 100 mL (0.100 L) and the moles of sodium chloride are computed by using its molar mass (58.45 g/mol):
[tex]mol_{solute}=4g*\frac{1mol}{58.45g} =0.0684mol[/tex]
Therefore, the molarity is:
[tex]M=\frac{0.0684mol}{0.100L} \\\\M=0.684\frac{mol}{L}=0.684M[/tex]
Regards.
What are the correct half reactions for the following reaction: Cu2+ + Mg -> Cu + Mg2+
Answer:
Cu2 + 2Mg-> 2Cu+ Mg2
Explanation:
Balance the equation and make sure both the reactant and the products are the same
Hope it will be helpful
[tex]Cu^{+2} + 2Mg[/tex] -> [tex]2Cu + Mg^+2[/tex] is the correct half-reactions.
What is a balanced equation?A balanced equation is an equation for a chemical reaction in which the number of atoms for each element in the reaction and the total oxidation numbers is the same for both the reactants and the products.
[tex]Cu^{+2} + 2Mg[/tex] -> [tex]2Cu + Mg^+2[/tex] is the correct half-reactions.
Magnesium is oxidized because its oxidation state increased from 0 to +2 while Cu is reduced because its oxidation state decreased from +2 to 0.
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Nombre de la siguiente estructura de compuesto orgánico
Answer:
Nombre de la siguiente estructura de compuesto orgánico
Explanation:
Calculate the energy required to heat 566.0mg of graphite from 5.2°C to 23.2°C. Assume the specific heat capacity of graphite under these conditions is ·0.710J·g−1K−1 . Be sure your answer has the correct number of significant digits.
Answer:
7.23 J
Explanation:
Step 1: Given data
Mass of graphite (m): 566.0 mgInitial temperature: 5.2 °CFinal temperature: 23.2 °CSpecific heat capacity of graphite (c): 0.710J·g⁻¹K⁻¹Step 2: Calculate the energy required (Q)
We will use the following expression.
Q = c × m × ΔT
Q = 0.710J·g⁻¹K⁻¹ × 0.5660 g × (23.2°C-5.2°C)
Q = 7.23 J
Name the following alkane molecule:
Br
CI
A. 6-bromo-2-chlorodecane
B. 2-chloro-6-bromodecane
C. 5-bromo-9-chlorodecane
Answer:
6- bromo- 2-chlorodecane
The name of molecule is 6- bromo- 2-chlorodecane.
What is 6- bromo- 2-chlorodecane?
It is organic molecule. There are 10 carbon present in this molecule. The bromine atom is attached with C-6 carbon where chlorine is attached with C-2 carbon.
What is molecule?A molecule is a collection of more than one atom bound together by chemical bonds; depending on the context, the phrase may or may not include ions that meet this requirement.
Therefore, the name of the given molecule will be 6- bromo- 2-chlorodecane
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What is the initial temperature (°C) of a system that has the pressure decreased by 10 times while the volume increased by 5 times with a final temperature of -123°C?
Answer:
27°C or 300K
Explanation
We were told that the pressureof the system decreased by 10 times implies that P2= P1/10
Where P2=final pressure
P1= initial pressure
Wew were also told that the volume of the system increased by 5 times this implies that V2= 5×V1
Where T2= final temperature =-123C= 273+(-123C)=150K
T1= initial temperature
But from gas law
PV=nRT
As n and R are constant
P1V1/T1 = P2V2/T2
T1= P1V1T2/P2V2
T1=2×T2
T1=2×150
T1=300K
=300-273
=27°C
the initial temperature (°C) of a system is 27°C