The following compounds have similar molecular weights. Which has the highest boiling point?
A. CH3OCH3
B. C2H5OH
C. CH3CH2CH3
D. CH3CH=O

Answer:

-176.0 kJ/mol

Explanation:

Let's consider the following balanced reaction.

NH₃(g) + HCl(g) → NH₄Cl(s)

We can calculate the standard enthalpy change for the reaction (ΔH°rxn) using the following expression.

ΔH°rxn = 1 mol × ΔH°f(NH₄Cl(s)) - 1 mol × ΔH°f(NH₃(g)) - 1 mol × ΔH°f(HCl(g))

ΔH°rxn = 1 mol × (-314.4 kJ/mol) - 1 mol × (-46.1 kJ/mol) - 1 mol × (-92.3 kJ/mol)

ΔH°rxn = -176.0 kJ/mol

Answer:

amount of fertaliser--> the independant variable is the one being changed

Answer:

139/56 Ba

Explanation:

In writing nuclear equations, there must be a balance of the mass and charge on both sides of the reaction equation. That is, the sum of masses on the lefthand side of the nuclear reaction equation must equal the sum of masses on the righthand side of the nuclear reaction equation. Similarly, the charges on the lefthand side of the nuclear reaction equation must equal the sum of the charges on the right hand side of the nuclear reaction equation.

Hence, the isotope of barium formed in the equation mentioned in the question is 139/56 Ba.

Answer:

c. 2 OH⁻(aq) + 2 H⁺(aq) ⇒ 2 H₂O(l)

Explanation:

Step 1: Write the molecular equation

The molecular equation includes all the molecular species.

H₂A(aq) + 2 NaOH(aq) ⇒ Na₂A(aq) + 2 H₂O(l)

Step 2: Write the complete ionic equation

The complete ionic equation includes all the ions and the molecular species.

2 H⁺(aq) + A²⁻(aq) + 2 Na⁺(aq) + 2 OH⁻(aq) ⇒ 2 Na⁺(aq) + A²⁻(aq) + 2 H₂O(l)

Step 3: Write the net ionic equation

The net ionic equation includes only the ions that participate in the reaction and the molecular species.

2 OH⁻(aq) + 2 H⁺(aq) ⇒ 2 H₂O(l)

Answer: 11.2 days

Explanation:

Expression for rate law for first order kinetics is given by:

[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]

where,

k = rate constant

t = age of sample

a = let initial amount of the reactant

a - x = amount left after decay process  

a) for completion of half life:

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

[tex]t_{\frac{1}{2}}=\frac{0.693}{k}[/tex]

[tex]k=\frac{0.693}{5.6days}=0.124days^{-1}[/tex]

b) for completion of 75% of reaction

[tex]t=\frac{2.303}{0.124}\log\frac{100}{100-75}[/tex]

[tex]t=\frac{2.303}{0.124}\log\frac{100}{25}[/tex]

[tex]t=11.2days[/tex]

The time for which she has to perform the experiment is 11.2 days

Answer:

c) CH₃Cl

Explanation:

Due the relative abundance of chlorine and bromine. It is possible to determine which of the halogens is present in a mass spectrum of a organic compound:

The Cl-35, Cl-37 have a relative abundance of 75/25; Br-79 and Br-81 of 50/50.

For that reason, if a compound has a M/M+2 ratio of 75:25 you can be sure the compound has 1 Cl in its structure. Thus, the only possible structure is:

Answer:

V = 5 cm³

ρ = 4 g/cm³

Explanation:

Step 1: Calculate the volume (V)

We have a wooden cuboid of dimensions 5 cm × 1 cm × 1 cm. We can calculate its volume using the following expression.

V = 5 cm × 1 cm × 1 cm

V = 5 cm³

Step 2: Calculate the density (ρ)

The density is equal to the mass divided by the volume.

ρ = m / V

ρ = 20 g / 5 cm³

ρ = 4 g/cm³

Answer:

14.0 g

Explanation:

Step 1: Given data

Volume of solution (%w/v): 255 mL

Weight/volume % of glucose (solute): 5.50% (m/v)

Step 2: Calculate the mass of glucose

We can calculate the mass of glucose using the following expression.

%w/v = mass of glucose / milliters of solution × 100%

mass of glucose = %w/v × milliters of solution / 100%

mass of glucose = 5.50% (m/v) × 255 mL / 100%

mass of glucose = 14.0 g

The correct answer with  the correct number of decimal places and  number of significant figures is 109.302 g.

Significant figures are used for establishment  of a number which is presented in the form of digits. These digits give a meaningful representation  to the numbers.

The significant figures are the significant digits which convey the meaning according to the accuracy. These provide precision to the numbers and hence are called as significant numbers.There are rules for counting significant figures which are as follows:

1)All non-zero digits are significant .

2)All zeroes which occur between non-zero digits are significant.

3)All zeroes to the left and right of  a non-zero digit are not significant.

4) All zeroes on right  of decimal are significant if a non-zero number follows them.

5)All zeroes on right side of non-zero digit are significant.

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#SPJ5

They use something called Mullerian mimic so they will be protected from predators  

Explanation:

Answer:

Yes

Explanation:

All living things do have cells

Answer:

yes they all have to have cells for every living thing

Explanation:

if their was no cells in existence all the living will soon to be dead.

Answer: C. Cold air is more dense than hot air.

Explanation: Took the test on edmentum

If you mean cubic cm, then it will be about 10 grams

Answer:

One.

Explanation:

Hello,

In this case, the equilibrium condition is characterized by the equality of the rates at which a process happen and the contrary process happen, so its ratio is 1. For instance, a chemical reaction at equilibrium will have a contant ratio of the velocity at which the products are formed and the reactants consumed

However, for the described insoluble solid that is allowed the reach equilibrium, the ratio of the rate at which ions join the solution and the rate at which ions join the lattice will be one since it reaches an equilibrium state.

Best regards.

Answer:

I would suggest wearing safety glasses as it minimizes the chance of harmful chemicals entering the eyes

Explanation:

Answer: use you imagination

Explanation:

if you don’t know and will never know, just guess

Answer:

Shake it, imagine whats in it, or leave it alone.

Answer:

a. Tadpoles possess the tendency to grow more rapidly close to the cooling water released from the power plant as the temperature is greater in these waters, permitting them to acquire more nutrients. Thus, in the given case, the factor is the temperature of the system.  

b. In the given case, the factor is the catalyst, and in the given case enzymes are the biological catalyst. An enzyme increases the rate of the reaction as they lower the activation energy.  

c. In the given case, the factor is the enzyme, as the blood comprises an enzyme, peroxidase, which catalyzes the decomposition of hydrogen peroxide.  

Answer:

Have only single bonds.

Explanation:

Hello,

In this case, we need to remember that saturation is a state at which a carbon chain contains no insaturations, that is neither double nor triple bonds such case are alkenes and alkynes, but saturations only which are characterized by the presence of single bonds between adjacent carbon atoms. Such is the case of ethane (CH₃-CH₃), propane (CH₃-CH₂-CH₃), butane (CH₃-CH₂-CH₂-CH₃) and so on.

Best regards.

Answer:

[tex]pH=3.97[/tex]

Explanation:

Hello,

In this case, for the calculation of the pH of the given buffer we need to use the Henderson-Hasselbach equation:

[tex]pH=pKa+log(\frac{[base]}{[acid]} )[/tex]

Whereas the pKa for benzoic acid is 4.19, the concentration of the base is 0.15 M (sodium benzoate) and the concentration of the acid is 0.25 M (benzoic acid), therefore, the pH turns out:

[tex]pH=4.19+log(\frac{0.15M}{0.25M} )\\\\pH=3.97[/tex]

Regards.

Answer:

mass (gram), volume (litre) and length (metre)

Explanation:

Matter is usually defined as anything that has mass and can occupy space. Matter exists primarily in three forms; solid, liquid or as a gas. Some of the properties of matter and there corresponding metric units are listed below

Properties ⇒ Metric unit

Mass         ⇒ gram

Volume    ⇒ litre

length       ⇒ metre

Answer:

[tex]M=0.0256M[/tex]

Explanation:

Hello,

In this case, the undergoing chemical reaction is:

[tex]PbSO_4(aq)+2KCl(aq)\rightarrow PbCl_2(s)+K_2SO_4(aq)[/tex]

In such a way, since all the lead (II) is converted due to the excess of potassium chloride, the moles of lead (II) in the sample are computed from the mass of lead (II) sulfate:

[tex]n_{Pb^{2+}}=12.8gPbSO_4*\frac{1molPbSO_4}{303.3gPbSO_4} *\frac{1molPb^{2+}}{1molPbSO_4} \\\\n_{Pb^{2+}}=0.0422molPb^{2+}[/tex]

Thus, since volume of the solution is 1.65 due to the fact that the addition of the reactants is not enough to significantly modify the reaction's volume, the resulting molar concentration of the lead (II) ions is:

[tex]M=\frac{n_{Pb^{2+}}}{V}=\frac{0.0422molPb^{2+}}{1.65L}\\ \\M=0.0256M[/tex]

Regards.

Answer:

Benzene must be kept away from flames.

Explanation:

Edguenuity 2020

The most accurate statement about Benzene is :  Keep Benzene away from flames.

Although your question is incomplete a general answer is provided based on the MSDS provided in the question

Benzene is a colorless gas that exhibits a high level of flammability, it also has a sweet odor just like gasoline, it is a cancer-causing agent when humans are exposed to it for too long. based on its flammability it is advisable to keep flammable materials and flammable sources ( flames ) away from Benzene. and to also reduce the rate of human exposure to benzene as well.

Therefore we can conclude that based on the MSDS provided in the question the most accurate statement about benzene is Benzene should be kept away from flames.

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Answer:

83 atoms

Explanation:

5*(1 fe + 2 S) + 6(2 C + 4H + 2O) + 2*2(1 Ca + 2 H + 1 P + 4 O) = 15 + 36 + 32 = 83 atoms

Answer:

F.    [tex]\mathsf{\Delta G^0 \simeq -29.4 \ kJ}[/tex]

Explanation:

GIven that:

The chemical equation for the reaction is:

[tex]\mathtt{Fe_2O_{3(s)} + 3CO_{(g)} \to 2Fe _{(s)} + 3CO_{2(g)}}[/tex]

The value of the ΔG° (kJ/mol) at 25 °C

[tex]\Delta G^0 = \begin {pmatrix} 2( \Delta G_f^0 \ Fe_{(s)} )+ 3 ( \Delta G_f^0 \ CO_{2(g)} ) - 1 ( \Delta G_f^0 \ Fe_2CO_3_{(s)} + 3 ( ( \Delta G_f^0 \ CO _{(g)} ) \end {pmatrix}[/tex]

where;

[tex]\Delta G_f^0 \ Fe_{(s)} = 0[/tex]

[tex]\Delta G_f^0 \ CO_{2(g)} = -394.359 \ kJ/mole[/tex]

[tex]\Delta G_f^0 \ Fe_2CO_3_{(s)} = -742.2 \ kJ/mole[/tex]

[tex]\Delta G_f^0 \ CO _{(g)}= -137.168\ kJ/mole[/tex]

Replacing the values ; we have

[tex]\Delta G^0 = \begin {pmatrix} 2(0 )+ 3 ( -394.359 ) ) -( 1 (-742.2) + 3 (-137.168 ) \end {pmatrix}[/tex]

[tex]\Delta G^0 = \begin {pmatrix} 0 -1183.077 ) -(-742.2- 411.504 \end {pmatrix}[/tex]

[tex]\Delta G^0 = \begin {pmatrix} -1183.077 +742.2+ 411.504 \end {pmatrix}[/tex]

[tex]\mathtt{\Delta G^0 = -29.373 \ kJ}[/tex]

[tex]\mathsf{\Delta G^0 \simeq -29.4 \ kJ}[/tex]

Answer:

A - chemical changes

B - Physical changes

C - Chemical changes

D - Chemical changes

Explanation:

First and foremost, a chemical change is an irreversible change in the chemical properties of a substance leading to the formation of a new substance or substances while a physical change is a reversible change to the properties of a substance.

The burning of a match stick is an irreversible process involving the reaction of the various component of the match head (potassium chlorate, sulfur, glass powder) with that of the side of the box holding the match (phosphorus, binder, glass powder). Hence, it is considered a chemical reaction.

Warming of the metal is a reversible process and hence, a physical reaction. Warming involves a rise in temperature due to the heating. Once the heat source is removed and the metal allowed to stay for a while, its temperature will return back to the original temperature.

Water condensation and deposition of soot on the metal can be considered a chemical reaction. A reaction that leads to the formation of, at least, one new product is definitely a chemical reaction.

Answer:

I think a is the best answer. but really I can not confirm that.sorry for that.

The experimental methods which cannot be used to measure the rate of a chemical reaction is: B. measurement of the equilibrium concentration of an acidic product via titration with a strong base.

A chemical reaction can be defined as a chemical process which involves the continuous transformation (rearrangement) of the ionic, atomic or molecular structure of a chemical element by breaking down and forming chemical bonds, so as to produce a new chemical compound.

The rate of a reaction is also known as reaction rate and it refers to the speed at a which the reactants in a chemical reaction are transformed into products. Some of the factors that affect the rate of a reaction are:

In Chemistry, an experimental method which cannot be used to measure the rate of a chemical reaction is the measurement of the equilibrium concentration of an acidic product by titrating it with a strong base because the concentration of product always remain the same.

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Answer:

It has no effect on the metal.

Explanation:

Hello,

In this case, we must remember that metabolic acidosis is related with the presence of an excess of acidic substances in the blood as a result of higher levels carbon dioxide in the lungs or lower levels of bicarbonate in the blood as well. Nevertheless, since titanium is a metal unlikely to be chemically modified by those weak acids such as carbonic acid in the blood, we can infer that it has no effect on the metal when used in an artificial hip replacement.

Regards.

Answer:

The correct option is H₂

Explanation:

An ideal gas is the gas that obeys the gas laws perfectly. There molecules occupy little/negligible space with no interaction. Since they occupy negligible space, it can be said that the smaller the molecule of a gas, the more it behaves like an ideal gas. There size also accounts for there weak intermolecular force between it's molecules.

From the explanation above, H₂ has the smallest molecule and hence will behave the most like an ideal gas.

The gases that one would expect to behave the most ideally even under extreme conditions is H2.

H2 is simply known as a molecule of hydrogen that has two hydrogen atoms which are bonded to each other by covalent bond.

Due to the fact that the hydrogen atom has a smaller size and lesser electronegativity the hydrogen molecule is thus regarded to be the least polar.

N2 is known to have greater polarizability than hydrogen molecule and thus cannot be the answer.

Note that for a gas to behave ideally, the attractive and repulsive intermolecular forces need to be negligible. When looking at the three molecules

H2,N2,CO, the molecule which is most polar will behave least ideally.

Therefore, hydrogen molecule will have the least intermolecular forces and will be most ideal.

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Answer:

Explanation:

as we know that

1g =1000mg

so

10g=10*1000

10g=10000