^^^^Changes in state of matter are ALWAYS changes.

Answer:

Physical and psychological dependence is high, and withdrawal symptoms include watery eyes, runny nose, loss of appetite, irritability, tremors, panic, abdominal cramps and diarrhea, nausea, chills, and sweating. Use of contaminated syringes/needles to inject drugs may result in serious blood borne infections such as HIV-AIDS and hepatitis.

Answer:

The right answer is "3 g".

Explanation:

Given:

Initial mass substance,

[tex]M_0=24 \ g[/tex]

By using the relation between half lives and amount of substances will be:

⇒ [tex]M=\frac{M_0}{2^n}[/tex]

        [tex]=\frac{24}{2^3}[/tex]

        [tex]=3 \ g[/tex]

Thus, the above is the correct answer.

Answer:

[tex]d=4.24x10^{-4}\frac{lb}{in^3}[/tex]

Explanation:

Hello there!

In this case, according to the given information, it turns out firstly necessary for us to set the equation for the calculation of density and mass divided by volume:

[tex]d=\frac{m}{V}[/tex]

Thus, we can find the mass of the unknown by subtracting the total mass of the liquid to the mass of the flask and the liquid:

[tex]m=552.4g-464.7g=87.7g[/tex]

So that we are now able to calculate the density in g/mL first:

[tex]d=\frac{87.7g}{27.8mL}=3.15g/mL[/tex]

Now, we proceed to the conversion to lb/in³ by using the following setup:

[tex]d=3.15\frac{g}{mL}*\frac{1lb}{453.6g}*\frac{1in^3}{16.3871mL}\\\\d=4.24x10^{-4}\frac{lb}{in^3}[/tex]

Regards!

Based on the expression given in the question, X is the effective nuclear charge, and it increases down a group.

Effective nuclear charge is the net nuclear charge that an electron in an atom experiences, after subtracting the nuclear charge shielded by other electrons.

The effective nuclear charge is denoted by Zeff and can be calculated by subtracting the number of shielding electrons from the atomic number.

Therefore, based on the expression given in the question, X is the effective nuclear charge, and it increases down a group.

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Answer:

1.27 × 10⁵ L

Explanation:

Step 1: Given data

Step 2: Convert the temperatures to the Kelvin scale

We will use the following expression.

K = °C + 273.15

K = 21 °C + 273.15 = 294 K

K = -48 °C + 273.15 = 225 K

Step 3: Calculate the final volume of the balloon

We will use the combined gas law.

P₁ × V₁ / T₁ = P₂ × V₂ / T₂

V₂ = P₁ × V₁ × T₂/ T₁ × P₂

V₂ = 745 Torr × 1.41 × 10⁴ L × 225 K/ 294 K × 63.1 Torr

V₂ = 1.27 × 10⁵ L

Answer: Mendeleev predicted elements that would later be discovered.

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Answer:

The pH is greater than 7 at the equivalence point.

Explanation:

Equivalence point is the point where the acid reacts with the base as stipulated in the equation of the reaction.

When a weak acid and a strong base are titrated, the pH of the solution at equivalence point is actually found to be around about pH ~ 9.

Hence, for a weak acid and strong base titration, The pH is greater than 7 at the equivalence point.

A titration between a weak acid and a strong base yields a solution whose pH is greater than 7 at the equivalence point.

Weak acids are acids which only ionize partially in aqueous solutions.

When weak acids are dissolved in water, they produce only few hydrogen ions.

A strong base on the other hand ionizes completely to produce hydroxide ions in aqueous solutions.

The titration of a weak acid and a strong base gives a solution whose pH is greater than 7 at equivalence point.

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Molar mass of Acetone

Now

Moles of Acetone:-

Amount of heat:-

Answer:

they are the end results so they are after the yields symbol

Explanation:

Answer:

725.15 L

Explanation:

The balanced chemical equation for the reaction between Na₂O₂ and CO₂ is the following:

Na₂O₂ + CO₂ → Na₂CO₃ + 1/2 O₂

From the stoichiometry of the reaction, 1 mol of Na₂O₂ reacts with 1 mol CO₂. So, the stoichiometric ratio is 1 mol Na₂O₂/1 CO₂.

Now, we convert the mass of reactants to moles by using the molecular weight (Mw) of each compound:

Mw (Na₂O₂) = (23 g/mol x 2) + (16 g/mol x 2) = 78 g/mol

moles Na₂O₂ = 96.7 g/(78 g/mol) = 1.24 mol Na₂O₂

Mw (CO₂) = 12 g/mol + (16 g/mol x 2) = 44 g/mol

moles CO₂ = 0.0755 g/(44 g/mol) = 1.71 x 10⁻³ mol CO₂

Now, we calculate the number of moles of CO₂ we need to completely react with the mass of Na₂O₂ we have:

1.24 mol Na₂O₂ x 1 mol CO₂/1 mol Na₂O₂ = 1.24 mol CO₂

In 1 L of respired air we have 1.71 x 10⁻³ mol CO₂ (0.0755 g), so we need the following number of liters to have 1.24 mol of CO₂:

1.24 mol CO₂ x 1 L/1.71 x 10⁻³ mol CO₂ = 725.15 L

Explanation:

Chemical reactions can exhibit different rate constants at differing:

i)initial concentrations

ii)volumes of container

iii) temperatures

iv)none of the above.

The rate constant of a reaction is constant at a particular temperature.

It is not depending on the initial concentration of the reactants. It varies with temperature.

Thus, among the given options the correct answer is Temperatures.

Chemical reactions can exhibit different rate constant at different temperatures. Hence, the correct option is temperature.

The rate constant is the proportionality constant in the equation that expresses the relationship between the rate of a chemical reaction and the concentrations of the reacting substances.

Chemical reactions proceed at vastly different speeds depending on the nature of the reacting substances, the type of chemical transformation, the temperature, etc.

For a given reaction, the speed of the reaction will vary with the temperature, the pressure, and the amounts of reactants present.

The rate constant goes on increasing as the temperature goes up, but the rate of increase falls off quite rapidly at higher temperatures.

On the other hand, the volume of the container, initial concentration does not affect the rate constant.

Therefore, Chemical reactions can exhibit different rate constant at different temperatures. Hence, the correct option is temperature.

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Answer:

[tex]\Delta G=-541.4kJ/mol[/tex]

Explanation:

Hello there!

In this case, according to the given information, it turns out firstly necessary to write out the described chemical reaction as shown below:

[tex]H_2+F_2\rightarrow 2HF[/tex]

Now, we set up the expression for the calculation of the standard free energy change, considering the free energy of formation of each species, specially those of H2 and F2 which are both 0 because they are pure elements:

[tex]\Delta G=2\Delta G_f^{HF}-(\Delta G_f^{H_2}+\Delta G_f^{F_2})\\\\\Delta G=2*-270.70kJ/mol-(0kJ/mol+0kJ/mol)\\\\\Delta G=-541.4kJ/mol[/tex]

Regards!

Answer:

Four common types of reactions involving carbonyl reactions: 1) nucleophilic addition; 2) nucleophilic acyl substitution; 3) alpha substitution; 4) carbonyl condensations. The first two were previously discussed and the second two involve the properties of the carbon directly adjacent to the carbonyls, α carbons.

Alpha-substitution reactions results in the replacement of an H attached to the alpha carbon with an electrophile.  

The nucleophile in these reactions are new and called enols and enolates.

Explanation:

The carbon in the carbonyl is the reference point and the alpha carbon is adjacent to the carbonyl carbon.  

Hydrogen atoms attached the these carbons denoted with Greek letters will have the same designation, so an alpha hydrogen is attached to an alpha carbon.  

Aldehyde hydrogens not given Greek leters.  

α hydrogens display unusual acidity, due to the resonance stabilization of the carbanion conjugate base, called an enolate.  

Tautomers are readily interconverted constitutional isomers, usually distinguished by a different location for an atom or a group, which is different than resonance.  

The tautomerization in this chapter focuses on the carbonyl group with alpha hydrogen, which undergo keto-enol tautomerism.  

Keto refers to the tautomer containing the carbonyl while enol implies a double bond and a hydroxyl group present in the tautomer.  

The keto-enol tautomerization equilibrium is dependent on stabilization factors of both the keto tautomer and the enol tautomer, though the keto form is typically favored for simple carbonyl compounds.  

The 1,3 arrangement of two carbonyl groups can work synergistically to stabilize the enol tautomer, increasing the amount present at equilibrium.

The positioning of the carbonyl groups in the 1,3 arrangement allows for the formation of a stabilizing intramolecular hydrogen bond between the hydroxyl group of the enol and the carbonyl oxygen as well as the alkene group of the enol tautomer is also conjugated with the carbonyl double bond which provides additional stabilization.

Aromaticity can also stabilize the enol tautomer over the keto tautomer.

Under neutral conditions, the tautomerization is slow, but both acid and base catalysts can be utilized to speed the reaction up.  

Biological enol forming reactions use isomerase enzymes to catalyze the shifting of a carbonyl group in sugar molecules, often converting between a ketose and an aldose in a process called carbonyl isomerization.

Answer:

Cu+(aq)--->Cu2+(aq) + e- : oxidation

reason: there is loss of electrons.

I2(s) + 2e--->2I-(aq) : reduction

reason: There is reduction of electrons.

Answer:

no

Explanation:

Fluoride is not nucleophilic (having the tendency to donate electrons) enough to allow for the use of HF to cleave ethers in protic media(protic solvents are polar liquid compounds that have dissociable hydrogen atoms). The rate of reaction is comparably low, so that heating of the reaction mixture is required.

Answer:

a

Explanation:

Beer-Lambert Law shows the relationship between the factors affecting the absorbance of a sample in relation to the concentration. These factors are:

the concentration c, path length (l), and the molar absorptivity (ε).

As a result, more radiation is assimilated as the concentration rises, and the absorbance rises as well. However, the longer the path length, the increase in the number of molecules and the higher the absorbance.

Thus, the straight-line equation for Beer-Lambert's law is:

A = εcl

From the above explanation, the option that doesn't relate to the deviations from linearity of Beer's law plot is in Option (a).

Answer:

the weakest base will have a higher Kb value since it will be closer to an acid than a base

7 kb values represents the weakest base.

Kb is the base dissociation constant which is a measure of how completely a base dissociates into its component ions in water. pKb is define as the negative base-10 logarithm of the base dissociation constant (Kb) of a solution.

Ka is define as the acid dissociation constant while pKa is the -log of this constant. Kb is define as the base dissociation constant, while pKb is the -log of the constant.

The acid and base dissociation constants are usually expressed in terms of moles per liter (mol/L).

Thus, 7 kb values represents the weakest base.

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Answer:

Explanation:

The reaction between 2 chloro- 2 methyl pentane and sodium iodide takes place through SN2 mechanism . iodide ion is the nucleophile which attacks the substrate . The rate of such reaction depends upon concentration of both the nucleophile and the substrate .

Hence rate of reaction will be increased by 2 x 2 = 4 times.

option D ) is correct.

Explanation:

The given reaction represents the reaction between a tertiary alkyl halide that is 2-chloro-2-methylpentane and a nucleophile that is NaI.

This reaction favors SN1 mechanism which has order one.

So, the given reaction follows first-order kinetics.

For a first-order reaction, the rate law is:

rate =k [A]

That means the rate of the reaction is dependent on the concentration of reactants.

So, when the concentration of the reactant is doubled then, the rate of the reaction is also doubled.

Among the given options the correct answer is option B) It would double the rate.

Answer:

[tex]V_2= 736mL[/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 combined gas law:

[tex]\frac{P_2V_2}{T_2}= \frac{P_1V_1}{T_1}[/tex]

Thus, we solve for the final volume by solving for V2 as follows:

[tex]V_2= \frac{P_1V_1T_2}{T_1P_2}[/tex]

Now, we plug in the variables to obtain the result in milliliters and making sure we have both temperatures in Kelvins:

[tex]V_2= \frac{1.20atm*735mL*279K}{(112+273)K*660/760atm}\\\\V_2= \frac{1.20atm*735mL*279K}{(112+273)K*660/760atm}=736mL[/tex]

Regards!

Answer:

Its atomic number is 14 and its atomic mass is 28. The most common isotope of uranium has 92 protons and 146 neutrons. Its atomic number is 92 and its atomic mass is 238 (92 + 146).

Answer:

R=k[D]^2

Explanation:

Given that it is a decomposition reaction;

D--->product

Hence;

The rate law is;

R= k[D]^x ----(1)

When we triple the concentration of D we have;

[D]' = [3D]^x

Therefore;

R'= 3R

R'= k[D]'----(2)

Hence dividing (1) by (2);

R/R' = k[D]^x/k[D]'

R/9R = k[D]^x/k[3D]^x

1/9 = 1/3^x (take inverse of both sides)

9 = 3^x

3^2 = 3^x

x= 2

Hence the rate law;

R=k[D]^2

Answer:

Following are the response to the given question:

Explanation:

The number of shells

n = 4

Calculating the spectral line:

[tex]= \frac{n(n-1)}{2}\\\\ = \frac{4(4-1)}{2} \\\\= \frac{4\times 3}{2}\\\\ = \frac{12}{2}\\\\ = 6[/tex]

Answer:

See explanation

Explanation:

Isomers are molecules which have the same molecular formula but different structural formulas. Sometimes, isomers may even contain different functional groups.

The formula C2H6O may refer to an ether or an alcohol. The compound could be CH3CH2OH(ethanol) or CH3OCH3(methoxymethane).

Hence, the functional isomers of the formula C2H6O are ethanol and methoxymethane.

Noble gas elements are almost always found as a single atom in nature.

An inert gas is a gas that does not undergo chemical reactions under a set of given conditions. The noble gases often do not react with many substances and were historically referred to as inert gases.

All noble gases have the maximum number of electrons in their outer shell; i.e. 2 electrons for helium and 8 for the other five.

Noble gases are monoatomic, which means they exist as single atoms. This is because of their electronic stability.

Thus, noble gas elements are almost always found as a single atom in nature. Hence, option C is correct.

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Answer:

hydrogen ions (H⁺) and chloride ions (Cl⁻)

Explanation:

Hydrochloric acid (HCl) is a strong acid. That means that the compound dissociates completely into ions when is dissolved in water, as follows:

HCl → H⁺ + Cl⁻

The equilibrium is completely shifted to the right side (products). Thus, it is considered that the concentration of the non-dissociated compound (HCl) is negligible, and the major specials present in the solution are the hydrogen ions (H⁺) and chloride ions (Cl⁻).

Answer:

The correct approach is "12.25°C".

Explanation:

Given:

Mass of lead,

mc = 245 g

Initial temperature,

tc = 300°C

Mass of Aluminum,

ma = 150 g

Initial temperature,

ta = 12.0°C

Mass of water,

mw = 820 g

Initial temperature,

tw = 12.0°C

Now,

The heat received in equivalent to heat given by copper.

The quantity of heat = [tex]m\times s\times t \ J[/tex]

then,

⇒ [tex]245\times .013\times (300-T) = 150\times .9\times (T-12.0) + 820\times 4.2\times (T-12.0)[/tex]

⇒             [tex]3.185(300-T) = 135(T-12.0) + 3444(T-12.0)[/tex]

⇒             [tex]955.5-3.185T=135T-1620+3444T-41328[/tex]

⇒                         [tex]43903.5 = 3582.185 T[/tex]

⇒                                  [tex]T = 12.25^{\circ} C[/tex]

Answer:

See explanation

Explanation:

Sugar is a polar crystalline substance. The sugar crystal is capable of dissolving in water since it is polar.

When sugar dissolves in water, a sugar solution is formed. If I want to separate the sugar from the water in the solution, I have to boil the solution to a very high temperature.

When I do that, the water in the sugar solution is driven off and the pure sugar crystal is left behind.

Answer:

False

Explanation:

Because Elaidic acid is an isomer of oleic acid. I really hope this helps you.

Answer:

Explanation:

The reaction between dimethyl malonate which is an active methylene group with an (∝, β-unsaturated carbonyl compound) i.e methyl vinyl ketone is known as a Micheal Addition reaction. The reaction mechanism starts with the base attack on the β-carbon to remove the acidic ∝-hydrogens and form a carbanion. The carbanion formed(enolate ion) attacks the methyl vinyl ketone(i.e. a nucleophilic attack at the β-carbon) to give a Micheal addition product, this is followed by the protonation to give the neutral product.