The question is incomplete, the complete question is;
Which aqueous solution has the highest vapor pressure at 25ºC?
15.0g of glucose (C6H12O6) in 100.0mL of water
25.0g of glucose (C6H12O6) in 100.0mL of water
15.0g of sucrose (C12H22O11) in 100.0mL of water
25.0g of sucrose (C12H22O11) in 100.0mL of water
Answer:
15.0g of sucrose (C12H22O11) in 100.0mL of water
Explanation:
The vapor pressure of a substance is a colligative property. Colligative properties are the properties of a substance that depend on the amount of solute present.
Since vapour pressure is a colligative property, we have to look out for the solution that has the lowest number of moles because as more solute is dissolved in the solvent, the vapor pressure of the solvent decreases.
Hence, 15.0g of sucrose (C12H22O11) in 100.0mL of water has the lowest number of moles in solution thus it is expected to exhibit the highest vapour pressure.
6. Calculate the percent yield when 0.631 g of precipitate is collected from the reaction of 35.0 mL of 0.100 M silver nitrate and 45.0 mL of 0.0800 M sodium bromide. Use the solubility rules to determine the identity of the precipitate.
Answer:
[tex]Y=96.0\%[/tex]
Explanation:
Hello there!
In this case, considering the reaction between silver nitrate and sodium bromide, whereby sodium nitrate and silver bromide are produced:
[tex]NaBr+AgNO_3\rightarrow NaNO_3+AgBr[/tex]
By bearing to mind the solubility rules, we infer the precipitate is silver bromide, whose moles are computed by using the molarity and volume of each reactant and then decide the correct value according to the limiting reactant:
[tex]n_{AgBr}=0.0350L*0.100molAgNO_3*\frac{1molAgBr}{1molAgNO_3}=0.00350mol AgBr\\\\n_{AgBr}=0.0450L*0.080molNaBr*\frac{1molAgBr}{1molNaBr}=0.0036molAgBr[/tex]
Thus, since sodium nitrate produces the smallest theoretical yield, we calculate the grams of silver nitrate precipitate by using the 0.00350 moles and its molar mass (187.77g/mol):
[tex]m=0.00350molAgBr*\frac{187.77gAgBr}{1molAgBr}=0.657g[/tex]
And finally the percent yield:
[tex]Y=\frac{0.631g}{0.657g}*100\%\\\\Y=96.0\%[/tex]
Regards!
What is a successful outcome for using a scientific method?
develop a theory. develop a hypothesis. support a hypothesis
You want to test how the mass of a reactant affect the speed of a reaction which of the following is an example of a controlled experiment to test this
Answer:A
Explanation:
The chemical equation of the reaction between Hydrogen and Oxygen is given below
H2 + O2 → H2O
(a) Write down the reactants and product of this reaction
(b) This chemical equation is not balanced . Why?
(c) Balance the given equation
9. Consider the given unbalanced reaction
Na + O2 → Na2O
(a) Find out the mono atomic and diatomic molecules in this equation
(b) What is the chemical compound present in this equation
(c) Balance the given equation
Answer:
1. a. The reactants are H₂ and O₂; The product is H₂O
b. The equation is not balanced because the number of atoms of the elements reacting is not equal to the number of atoms produced. 2 atoms of oxygen reacted but only one atom of oxygen is produced.
c. 2 H₂ + O₂ ---> 2 H₂O
2. a. The monotonic molecule is the sodium molecule, Na, since itnis made up of only one atom in its molecule.
The diatomic molecule is oxygen molecule, O₂, since it is made up of two atoms in its molecule.
b. The chemical compound present is sodium oxide, Na₂O
c. 4 Na + O₂ ---> 2 Na₂O
Explanation:
In a chemical reaction, the reactants are the elements or compounds which are converted to a new substance whichnis known as the product. The products are the new substances formed from the reactants.
In the given equation of reaction below;
H₂ + O₂ ---> H₂O
a. The reactants are H₂ and O₂; The product is H₂O
b. The equation is not balanced because the number of atoms of the elements reacting is not equal to the number of atoms produced. 2 atoms of oxygen reacted but only one atom of oxygen is produced.
c. 2 H₂ + O₂ ---> 2 H₂O
2. Given the reaction equation below:
Na + O₂ ---> Na₂O
a. The monotonic molecule is the sodium molecule, Na, since it is made up of only one atom in its molecule.
The diatomic molecule is oxygen molecule, O₂, since it is made up of two atoms in its molecule.
b. The chemical compound present is sodium oxide, Na₂O since itconsists of two chemically combined elements, sodium and oxygen.
c. 4 Na + O₂ ---> 2 Na₂O
Who at the top of the food web
Answer and Explanation:
Humans are one of the organisms at the top of a food web. Other animals are Orcas, Lions, Raptors, and others. These animals are called Ape.x Predators, because they are at the top of the food web.
#teamtrees #PAW (Plant And Water)
This is a quiz not a question from cambridge!
What is 2NaOH + Cl2→NaCl + NaOCl + H2O???
Answer::::
As products sodium chloride, sodium chlorate(I) and water are given. Hot concentrated Chlorine reacts with hot and concentrated sodium hydroxide solution to form sodium chloride and sodium chlorate.
Answer:
the answer is it's a balance chemical equation.
Explanation:
hope this helps u!!
What is the name of this compound?
Answer:
THERE IS NOTHING MENTION HERE HOW CAN ANYONE KNOW ABOUT IT?]
Explanation:
What is the mass of Na2CO3 required to make a
500 mL standard solution of 0.400 mol/L Na2CO3?
a. 212 g
b. 23.4 g
c. 25.8 g
d. 27.39
Answer:
21.2 g
Explanation:
Step 1: Given data
Molar concentration of the solution (C): 0.400 mol/LVolume of solution (V): 500 mL (0.500 L)Step 2: Calculate the moles of Na₂CO₃ (solute) in the solution
We will use the definition of molarity.
C = moles of solute / liters of solution
moles of solute = C × liters of solution
moles of solute = 0.400 mol/L × 0.500 L = 0.200 mol
Step 3: Calculate the mass corresponding to 0.200 moles of Na₂CO₃
The molar mass of Na₂CO₃ is 105.99 g/mol.
0.200 mol × 105.99 g/mol = 21.2 g
20. What is an irreversible change?
Answer:
A change is called irreversible if it cannot be changed back again. For example you cannot change a cake back into its ingredients again. Irreversible changes are permanent.
Explanation:
Hope this helps!! :))
When the following aqueous solutions are mixed together, a precipitate forms. Balance the net ionic equation in standard form for the reaction that occurs and determine the sum of the coefficients.
Sodium sulfide and silver nitrate - 3 or 4
Lead(II) nitrate and sodium chloride -3 or 4
Calcium nitrate and potassium carbonate - 3or 4
Barium nitrate and sodium hydroxide -3 or 4
Silver nitrate and sodium chloride -3 or 4
Answer:
For (a): The balanced net ionic equation is [tex]2Ag^{+}(aq)+S^{2-}(aq)\rightarrow Ag_2S(s)[/tex] and the sum of coefficients is 4
For (b): The balanced net ionic equation is [tex]Pb^{2+}(aq)+2Cl^{-}(aq)\rightarrow PbCl_2(s)[/tex] and the sum of coefficients is 4
For (c): The balanced net ionic equation is [tex]Ca^{2+}(aq)+CO_3^{2-}(aq)\rightarrow CaCO_3(s)[/tex] and the sum of coefficients is
For (d): The balanced net ionic equation is [tex]Ba^{2+}(aq)+2OH^{-}(aq)\rightarrow Ba(OH)_2(s)[/tex] and the sum of coefficients is 4
For (e): The balanced net ionic equation is [tex]Ag^{+}(aq)+Cl^{-}(aq)\rightarrow AgCl(s)[/tex] and the sum of coefficients is 3
Explanation:
Net ionic equation is defined as the equations in which spectator ions are not included.
Spectator ions are the ones that are present equally on the reactant and product sides. They do not participate in the reaction.
For (a): Sodium sulfide and silver nitrateThe balanced molecular equation is:
[tex]Na_2S(aq)+2AgNO_3(aq)\rightarrow 2NaNO_3(aq)+Ag_2S(s)[/tex]
The complete ionic equation follows:
[tex]2Na^{+}(aq)+S^{2-}(aq)+2Ag^+(aq)+2NO_3^{-}(aq)\rightarrow 2Na^+(aq)+2NO_3^-(aq)+Ag_2S(s)[/tex]
As sodium and nitrate ions are present on both sides of the reaction. Thus, they are considered spectator ions.
The net ionic equation follows:
[tex]2Ag^{+}(aq)+S^{2-}(aq)\rightarrow Ag_2S(s)[/tex]
Sum of the coefficients = [2 + 1 + 1] = 4
For (b): Lead(II) nitrate and sodium chlorideThe balanced molecular equation is:
[tex]2NaCl(aq)+Pb(NO_3)_2(aq)\rightarrow 2NaNO_3(aq)+PbCl_2(s)[/tex]
The complete ionic equation follows:
[tex]2Na^{+}(aq)+2Cl^{-}(aq)+Pb^{2+}(aq)+2NO_3^{-}(aq)\rightarrow 2Na^+(aq)+2NO_3^-(aq)+PbCl_2(s)[/tex]
As sodium and nitrate ions are present on both sides of the reaction. Thus, they are considered spectator ions.
The net ionic equation follows:
[tex]Pb^{2+}(aq)+2Cl^{-}(aq)\rightarrow PbCl_2(s)[/tex]
Sum of the coefficients = [2 + 1 + 1] = 4
For (c): Calcium nitrate and potassium carbonateThe balanced molecular equation is:
[tex]K_2CO_3(aq)+Ca(NO_3)_2(aq)\rightarrow 2KNO_3(aq)+CaCO_3(s)[/tex]
The complete ionic equation follows:
[tex]2K^{+}(aq)+CO_3^{2-}(aq)+Ca^{2+}(aq)+2NO_3^{-}(aq)\rightarrow 2K^+(aq)+2NO_3^-(aq)+CaCO_3(s)[/tex]
As potassium and nitrate ions are present on both sides of the reaction. Thus, they are considered spectator ions.
The net ionic equation follows:
[tex]Ca^{2+}(aq)+CO_3^{2-}(aq)\rightarrow CaCO_3(s)[/tex]
Sum of the coefficients = [1 + 1 + 1] = 3
For (d): Barium nitrate and sodium hydroxideThe balanced molecular equation is:
[tex]2NaOH(aq)+Ba(NO_3)_2(aq)\rightarrow 2NaNO_3(aq)+Ba(OH)_2(s)[/tex]
The complete ionic equation follows:
[tex]2Na^{+}(aq)+2OH^{-}(aq)+Ba^{2+}(aq)+2NO_3^{-}(aq)\rightarrow 2Na^+(aq)+2NO_3^-(aq)+Ba(OH)_2(s)[/tex]
As sodium and nitrate ions are present on both sides of the reaction. Thus, they are considered spectator ions
The net ionic equation follows:
[tex]Ba^{2+}(aq)+2OH^{-}(aq)\rightarrow Ba(OH)_2(s)[/tex]
Sum of the coefficients = [2 + 1 + 1] = 4
For (e): Silver nitrate and sodium chlorideThe balanced molecular equation is:
[tex]NaCl(aq)+AgNO_3(aq)\rightarrow NaNO_3(aq)+AgCl(s)[/tex]
The complete ionic equation follows:
[tex]Na^{+}(aq)+Cl^{-}(aq)+Ag^{+}(aq)+NO_3^{-}(aq)\rightarrow Na^+(aq)+NO_3^-(aq)+AgCl(s)[/tex]
As sodium and nitrate ions are present on both sides of the reaction. Thus, they are considered spectator ions.
The net ionic equation follows:
[tex]Ag^{+}(aq)+Cl^{-}(aq)\rightarrow AgCl(s)[/tex]
Sum of the coefficients = [1 + 1 + 1] = 3
How many moles of KCl are in
28g of KCl?
Answer:
0.38 moles KCl
Explanation:
(28 g KCl) / (74.55 g/mol KCl) = 0.38 moles KCl
Answer:
There are 0.38 moles of KCI in
28g of KCI.
Explanation:
This maybe correct.
as the temperature of a chemical in this gas phase is increased, the rate of the reaction increases because
Answer:
An increase in temperature typically increases the rate of reaction. An increase in temperature will raise the average kinetic energy of the reactant molecules. Therefore, a greater proportion of molecules will have the minimum energy necessary for an effective collision
Identify each of the following as endothermic or exothermic.
a. Water in a pond evaporates.
b. Methane gas burns on a stove top.
c. Water freezes to form ice.
d. Energy flows from the system to the surroundings.
e. Energy flows from the surroundings to the system.
Answer:
Identify each of the following as endothermic or exothermic.
a. Water in a pond evaporates.
b. Methane gas burns on a stovetop.
c. Water freezes to form ice.
d. Energy flows from the system to the surroundings.
e. Energy flows from the surroundings to the system.
Explanation:
An exothermic reaction is the one in which heat energy is released.
An endothermic reaction is one in which heat energy is absorbed.
a. Water in a pond evaporates.
This process absorbs heat energy.
Hence, this is an example of an endothermic process.
b. Methane gas burns on a stovetop and release heat energy and hence this is an example of an exothermic reaction.
c. Water freezes to form ice.
In this process heat energy is released.So this is an example of exothermic reaction.
d. Energy flows from the system to the surroundings.
That means heat energy is released into the surroundings.
So, this is an example of exothermic process.
e. Energy flows from the surroundings to the system.
That means energy is absorbed by the system.
So, it is an endothermic process.
PLEASE SOMEONE HELP ASAP: why does alcohol dissolve permanent marker
Explanation:
Isopropyl alcohol is the solvent used in whiteboard markers. When it comes into contact with the permanent marker, the solvent breaks the cohesive force between the ink molecules and the whiteboard by solubilising them (i.e. returning them to solution).
What is the direction and magnitude of the net dipole of CCl2F2
Answer:
Given molecule is CCl2F2.
What is the direction and magnitude of the net dipole of CCl2F2?
Explanation:
Dipole moment is a vector quantity.
The arrow end starts from a less electronegative atom and directs towards the more electronegative atom.
In the given molecule,
CCl2F2,
the central atom is carbon with sp3 hybridsation and there are no lone pairs on the central atom.
The molecule is tetrahedral but it is asymmetrical.
Because all the four bonded atoms are not same and there exists an electronegativity difference between F and Cl.
Hence, there exists a net dipole moment for the given molecule and the molecule is polar.
Choose the atom that has the largest atomic radius.
a. Cl
b. S
c. Na
d. Si
Answer:
the correct answer is option C. Na
For the balanced chemical reaction
>
C4H2OH + 602 > 4CO2 + 5H20
if you want to make 100 molecules of CO2, how many molecules of O2 will you need? Answer with a number only.
ITS
Answer:
150
Explanation:
C₄H₂OH + 6O2 → 4CO2 + 5H₂OWe can find the equivalent number of O₂ molecules for 100 molecules of CO₂ using a conversion factor containing the stoichiometric coefficients of the balanced reaction, as follows:
100 molecules CO₂ * [tex]\frac{6moleculesO_2}{4moleculesCO_2}[/tex] = 150 molecules O₂150 molecules of O₂ would produce 100 molecules of CO₂.
Intramolecular forces of attraction are important in holding large molecules together.
a. True
b. False
Answer:
False. Intermolecular forces of attraction are important in holding large molecules together.
Explanation:
Within a molecule, atoms are held together by intramolecular forces. That is, intramolecular forces are the attractive forces that hold the atoms or ions that make up chemical substances (elements and compounds) together, forming a chemical bond.
On the other hand, intermolecular forces are those that act on different molecules or ions and that make them attract or repel each other. In other words, intermolecular forces are those that occur between the different molecules of a compound, and cause these molecules or ions to attract or repel each other.
So, intermolecular forces of attraction are important in holding large molecules together.
which of the following elements are more reactive than the others.
A. calcium (Ca)
B. Magnesium (Mg)
C. potassium (K)
D. Sodium (Na)
Answer: c potassium.
Explanation:
potassium is the most reactive metal among the given options.
D is absolutely wrong.
Star
Planet
*
As the planet makes one completer revolution around the star, starting at the position shown the gravitational attraction between the star
and the planet will
A Continually decrease
3 Decrease, then increase
increase then decrease
Romain the same
RI
12.20 AM
618/2001
Answer:
according to the path shown in the figure it will start decreasing then again it will start increasing when the path will be nearer to the star.
Reason is gravitation force is indirectly proportional to the distance.
So, option B. decrease then increase is correct
The Kc for the following is 5.0 at 100 degrees Celsius.
If an equilibrium mixture contains 0.53 M NO2 what is the molar concentration of N2O4?
Answer:
1.40M = [N2O4]
Explanation:
Based on the reaction:
2NO2(g) ⇄ N2O4(g)
Kc is defined as:
Kc = 5.0 = [N2O4] / [NO2]²
Where [] are the concentrations in equilibrium of each gas
As the equilibrium concentration of NO2 is 0.53M:
5.0 = [N2O4] / [0.53]²
5.0 = [N2O4] / [0.2809]
5.0*0.2809 = [N2O4]
1.40M = [N2O4]How many significant figures are in a measurement of 28.050 km?
Answer:
has 5, ans 3 decimals.
thats as simple as i can put it.
Arrange the following molecules in order of decreasing polarity of their bonds.
a. PBr3
b. SF2
c. H2O
d. NCl3
Answer:
SF2 > H2O > PBr3 > NCl3
Explanation:
Compare the electronegativity values for the atoms and classify the nature of the bonding based on the electronegativity difference.
P has an electronegativity of 2.1, while Br has an electronegativity of 2.96. The difference is 0.86, indicating that these atoms will form covalent bonds.
S has an electronegativity of 2.58 while F has an electronegativity of 4.0. The difference is 1.42, indicating that these atoms will form polar covalent bonds.
O has an electronegativity of 3.5 while H has an electronegativity of 2.1. The difference is 1.4, indicating that these atoms will form polar covalent bonds.
N has an electronegativity of 3.04, whereas Cl has an electronegativity of 3.5. This difference of 0.46 indicates that these atoms will form covalent bonds.
We know that the greater the electronegativity, the higher the polarity. In decreasing order of polarity, we have:
SF2 > H2O > PBr3 > NCl3
Classify each phrase according to whether it applies to photophosphorylation, oxidative phosphorylation, or both
Photophosphorylation Oxidative phosphorylation Both
1. occurs in plants produces ATP
2. occurs in chloroplasts
3. occurs in mitochondria
4. involves a larger electrical component
5. involves a smaller electrical component
6. involves a proton gradient
Answer:
1. Both
2. Phosphorylation
3. Both
4. Phosphorylation
5. Oxidative.
6. Both
Explanation:
Phosphorylation only occurs in chloroplast and it involves larger electrical component. Both Phosphorylation and oxidative occurs in mitochondria and it involves proton gradient. They occur in plants to produce ATP. Oxidative involves in smaller electrical component.
Photophosphorylation is a process that captures the solar energy from the sun to transform it into chemical energy. It occurs in the chloroplast of a plant cell.
What are photophosphorylation and oxidative phosphorylation?Photophosphorylation is a process of converting solar energy from the sun to ATP needed by plants and other organisms for cellular function and activity. This process takes place in the chloroplast of the plant cell and requires electrical components.
Oxidative Phosphorylation is the process of producing ATP with the help of oxygen and enzymes hence, occurs in aerobic cells. It does not need a larger electrical component.
Both phosphorylation and oxidative phosphorylation occurs in the mitochondria of plants cells and involves a proton gradient for the formation of ATP.
Therefore, oxidative phosphorylation option 5. involves a smaller electrical component, phosphorylation option 2. occurs in the chloroplast, and option 4. needs a larger electrical component.
Learn more about phosphorylation here:
https://brainly.com/question/1870229
At a constant temperature of 30 °C, an ideal gas occupies 2.78 Liters at a pressure of 1.27 atm. What will be the volume (L) at a pressure of 3.95 atm?
Answer:
[tex]V_2=0.894L[/tex]
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to solve this problem by using the Boyle's law for an inversely proportional relationship between pressure and volume at constant temperature, as described in the problem statement:
[tex]P_2V_2=P_1V_1[/tex]
Thus, we solve for V2, final volume, to obtain the following result:
[tex]V_2=\frac{P_1V_1}{P_2} \\\\V_2=\frac{1.27atm*2.78L}{3.95atm}\\\\V_2=0.894L[/tex]
Regards!
Alkanes react with nitric acid to give what?
Answer:
The polyoxometalates initially abstract the hydrogen of the alkane to form the alkyl radical and the reduced polyoxometalates. The reduced polyoxometalates subsequently react with nitric acid to produce the oxidized form and nitrogen dioxide.
Explanation:
g .For each of the following disubstituted cyclohexanes, indicate whether the substituents in the two chair conformations would be both equatorial in one chair conformer and both axial in the other, or one equatorial and one axial in each of the two chair conformers. (a) Cis-1,2- (b) Trans-1,2- (c) Cis-1,3- (d) Trans-1,3- (e) Cis-1,4- (f) Trans-1,4-
Answer:
a) Both chairs conformers have one of its substituents in an axial position and the other in an equatorial position
b) One chair conformer has both its substituents in an axial position while the other chair has its substituents in an equatorial position
c) One chair conformer has both its substituents in an axial position while the other chair has its substituents in an equatorial position
d) Both chairs have one of its substituents in an axial position and the other in an equatorial position
e) Both chairs have one of its substituents in an axial position and the other in an equatorial position
(f) One chair conformer has both its substituents in an axial position while the other chair has its substituents in an equatorial position
Explanation:
Determine what the substituents would be
a) Cis-1,2- : Both chairs conformers have one of its substituents in an axial position and the other in an equatorial position
b) Trans-1,2- : One chair conformer has both its substituents in an axial position while the other chair has its substituents in an equatorial position
c) Cis-1,3- : One chair conformer has both its substituents in an axial position while the other chair has its substituents in an equatorial position
d) Trans-1,3- : Both chairs have one of its substituents in an axial position and the other in an equatorial position
e) Cis-1,4- : Both chairs have one of its substituents in an axial position and the other in an equatorial position
(f) Trans-1,4- : One chair conformer has both its substituents in an axial position while the other chair has its substituents in an equatorial position
What’s the answer to the question
Answer: B
Explanation: im pretty sure my teacher mentioned something about N--h bonds are non polar
Answer:
C
Explanation:
After being exposed to fire ant venom, crazy ants that were treated with formic acid has a significantly greater survival rate than those treated with a water-based control. In this experiment, these results suggested that:___________
Answer:
After being exposed to fire ant venom, crazy ants that were treated with formic acid has a significantly greater survival rate than those treated with a water-based control. In this experiment, these results suggested that:
Explanation:
That means formic acid increases its rate of survival.
So, formic acid acts in both ways as offensive and defensive ways to crazy ants.
Explain why each of the following names is incorrect
(a) 2,2-Dimethyl-6-ethylheptane
(b) 4-Ethyl-5,5-dimethylpentane
(c) 3-Ethyl-4,4-dimethylhexane
(d) 5,5,6-Trimethyloctane
(e) 2-Isopropyl-4-methylheptane
Explanation:
Alkanes are the hydrocarbons in which single bonds are present between the carbon atoms
The suffix for alkane hydrocarbons used is '-ane'. The rules to write the nomenclature of alkanes follows:
Select the longest possible continuous carbon chain and it will be the parent chainNumbering is done as such that the alkyl substituents are given the lowest numberIf different alkyl groups are present, they are written in an alphabetical order irrespective of their position in the carbon chainIf two or more similar alkyl groups are present, the words, di, tri, tetra, and so on are used to specify the number of times alkyl groups appearIf two or more alkyl groups are present and the branching occurs, the numbering is done which gives the minimum possible number to all the substituentsFor the given options:
(a) 2,2-Dimethyl-6-ethylheptane
The longest possible carbon chain has 8 carbon atoms (prefix used is 'oct-') and not 7(prefix used is 'hept-').
Thus, the correct IUPAC name will be 2,2,6-trimethyloctane.
(b) 4-Ethyl-5,5-dimethylpentane
The longest possible carbon chain has 6 carbon atoms (prefix used is 'hex-') and not 5(prefix used is 'pent-').
Thus, the correct IUPAC name will be 4-isopropylhexane.
(c) 3-Ethyl-4,4-dimethylhexane
The substituents are not given the minimum possible number. Total sum of the number in original compound = [4 + 4 + 3] = 11
But, if both the methyl groups are placed at 3rd position, then total sum of the number = [3 + 3 + 4] = 10
Thus, the correct IUPAC name will be 4-ethyl-3,3-dimethylhexane
(d) 5,5,6-Trimethyloctane
The substituents are not given the minimum possible number. Total sum of the number in original compound = [5 + 5 + 6] = 16
But, if both the methyl groups are placed at 3rd position and 4th position, then total sum of the number = [3 + 3 + 4] = 10
Thus, the correct IUPAC name will be 3,3,4-trimethyloctane
(e) 2-Isopropyl-4-methylheptane
The longest possible carbon chain has 8 carbon atoms (prefix used is 'oct-') and not 7 (prefix used is 'hept-').
Thus, the correct IUPAC name will be 2,3,5-trimethyloctane
The structures of the compounds are attached below.