Which are the following exothermic or endothermic

Absorbs Energy

-Hrxn

+Hrxn

Feels Hot

Heat flows from surrounds to Reaction

Not Energetically Favorable

Energetically Favorable

Releases Energy

Feels Cold

Heat flows from the reaction to the surrounds

Answer:

я не знаю ответа :(

Explanation:

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:

5×6.02×1023

Explanation:

there are 5×6.02×1023 molecules of p4010 in 5mole. there are four P atoms in a single molecule of p4010

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.

Answer:

Oxidation half-reaction: 2 Fe (s) ----> 2 Fe³+ (aq) + 6e-

Reduction half-reaction: 3 Pb²+ (aq) + 6 e- ----> 3 Pb (s)

Explanation:

A redox reaction reaction is one in which oxidation and reduction occur simultaneously and to the same extent.

Oxidation involves a loss of electron, hence, a positive increase in the oxidation number of the atom or ion. The oxidation half-reaction is as follows:

2 Fe (s) ----> 2 Fe³+ (aq)

The metallic element iron, Fe , having an oxidation number of zero, loses three electrons to form the Fe³+ ion with a charge of +3. Since each atom loses three electrons each, The number of moles of electrons lost is six.

2 Fe (s) ----> 2 Fe³+ (aq) + 6e-

Reduction involves a gain of electrons, hence, a decrease in the oxidation number of the atom or ion. The reduction half-reaction is given below:

3 Pb²+ (aq) ---> 3 Pb (s)

The lead (ii) ion, Pb²+ having a charge of +2 gains two electrons each to become the neutral metallic lead atom, Pb, with oxidation number of zero. Since 3 moles of Pb²+ are reacting, 6 moles of electrons are gained.

3 Pb²+ (aq) + 6 e- ----> 3 Pb (s)

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:

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:

True

Explanation:

When two atoms are at infinite distance from each other, the both atoms posses high energy.

However, as they begin to approach each other, the distance between them gradually decreases and so does their energy.

A point is eventually reached when the potential energy curve reaches its minimum value. The internuclear distance between the two atoms at this point is called the bond length of the system.

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:

[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:

a. 6mL of ethanol and 35mL of water: the solute is ethanol (smallest volume) and the solvent is water (greater volume).

b. 300 g of water containing 8g of NaHCO3: the solute is NaHCO3 (smallest mass) and the solvent is water (greater mass).

c. 0.005L of CO2 and 2L of O2: the solute is CO2 (smallest volume) and the solvent is O2 (greater volume).

Explanation:

Hello there!

In this case, according to the given problem, it turns out possible for us to solve these questions by bearing to mind the fact that in a solution, we can find two substances, solute and solvent, whereas the former is in a smaller proportion in comparison to the latter; in such a way, we infer the following:

a. 6mL of ethanol and 35mL of water: the solute is ethanol (smallest volume) and the solvent is water (greater volume).

b. 300 g of water containing 8g of NaHCO3: the solute is NaHCO3 (smallest mass) and the solvent is water (greater mass).

c. 0.005L of CO2 and 2L of O2: the solute is CO2 (smallest volume) and the solvent is O2 (greater volume).

Regards!

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

Answer:

4.77mol is the correct answer

Answer:

Explanation:

CCl4 => C + 2Cl2

Answer:

Explanation:

Can you provide a picture? I can outline the reactions though. a) will make a Z double bond from a triple bond and then peroxyacid can do epoxidation. b) will make the Z double bond then ozonolysis to double bond will create to aldehyde compounds. c) is essentially useless unless there is a ketone or aldehyde in the compound already since H2/Pd will fully reduce the alkyne (which I am assuming is present) and so the peroxyacid can't do epoxidation and can only do baeyer villiger oxidation, and d) reduces the alkyne to an E alkene and then do epoxidation to give an epoxide (with trans steroechemistry)

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:

fjskeowkcnekvo Dee five votes come vote for dog even r

Answer:

1. 1.00 gm

2. 50 ml

3. 38.93 ml

4. 11.07 ml

5. 0.01107 L

6. 0.010 moles / L

7. 0.0001107 moles

8. 0.0001107 moles

9. 0.00647042 grams

Explanation:

Silver nitrate can react with various compounds to form different products. The weight of products may be different from the original solution introduced due to combustion reaction, as heat energy is released during the chemical process.

Molar mass of Acetone

Now

Moles of Acetone:-

Amount of heat:-

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.

Answer:

The postabsorptive state (also called the fasting state) occurs when the food is already digested and absorbed, and it usually occurs overnight, when you sleep (if you skip meals for some days, you will enter in this state).

The catabolic state is the metabolic breakdown of molecules into simpler ones, releasing energy (heat) and utilizable resources.

Now, when you are in a postabsorptive state, the glucose levels start to drop, then the body starts to depend on the glycogen stores, which are catabolized into glucose, this is defined as the start of the postabsorptive state.

So yes, as the postabsorptive states, catabolic processes start to happen, so the statement is true.

Answer:

5.25 moles of protons. Option e

Explanation:

Reaction between phosphoric acid and sodium hydroxide is neutralization.

We can also say, we have an acid base equilibrium right here:

H₃PO₄  +  3NaOH →  Na₃PO₄  +  3H₂O

Initially we have 5.25 moles of base.

We have data from the acid, to state its moles:

M = mol/L, so mol = M . L

mol = 1.75 moles of acid

If we think in the acid we know:

H₃PO₄  →  3H⁺  +  PO₄⁻³

We know that 1 mol of acid can give 3 moles of protons (hydrogen ions)

If we have 1.75 moles of acid, we may have

(1.75 . 3) /1 = 5.25 moles of protons

These moles will be neutralized by the 5.25 moles of base

H₃O⁺  +  OH⁻  ⇄  2H₂O     Kw

In a titration of a weak acid and a strong base, we have a basic pH

Answer:

15.0 g

Explanation:

15.0% =0.150

100.0 g × 0.150= 15.0g

Sodium nitrate is "an inorganic compound with the formula of NaNO₃.

Inorganic compound is "a chemical compound that lacks carbon–hydrogen bonds".

15% = 0.15

100.0 g × 0.15= 15g

Hence, 15g of Sodium nitrate are needed to prepare 100 gms of a 15% by mass sodium nitrate.

To learn more about Sodium nitrate here

https://brainly.com/question/24256699

#SPJ2

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:

I do not speak Spanish.

Explanation:

Answer:

Al^3+

Explanation:

Solubility rules tell us what substances are soluble in water. Since NaCl was added and no precipitate was observed, the mercury II ion is absent.

Addition of Na2SO4 does not form a precipitate meaning that Ba^2+ is absent.

If a precipitate is formed when NaOH is added, the the ionic reaction is as follows;

Al^3+(aq) + 3 OH^-(aq) ------> Al(OH)3(s)

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.

To learn more about rate constant, click here:

https://brainly.com/question/24658842

Answer: The pH of 0.10 M [tex]Cu(NO_{3})_{2}(aq)[/tex] is 4.49.

Explanation:

Given: Initial concentration of [tex]Cu(H_{2}O)^{2+}_{6}[/tex] = 0.10 M

[tex]K_{a} = 1.0 \times 10^{-8}[/tex]

Let us assume that amount of [tex]Cu(H_{2}O)^{2+}_{6}[/tex] dissociates is x. So, ICE table for dissociation of  [tex]Cu(H_{2}O)^{2+}_{6}[/tex]  is as follows.

                               [tex]Cu(H_{2}O)^{2+}_{6} \rightleftharpoons [Cu(H_{2}O)_{5}(OH)]^{+} + H_{3}O^{+}[/tex]

Initial:                       0.10 M                       0                       0

Change:                    -x                              +x                      +x

Equilibrium:           (0.10 - x) M                    x                        x

As the value of [tex]K_{a}[/tex] is very small. So, it is assumed that the compound will dissociate very less. Hence, x << 0.10 M.

And, (0.10 - x) will be approximately equal to 0.10 M.

The expression for [tex]K_{a}[/tex] value is as follows.

[tex]K_{a} = \frac{[Cu(H_{2}O)^{2+}_{6}][H_{3}O^{+}]}{[Cu(H_{2}O)^{2+}_{6}]}\\1.0 \times 10^{-8} = \frac{x \times x}{0.10}\\x = 3.2 \times 10^{-5}[/tex]

Hence, [tex][H_{3}O^{+}] = 3.2 \times 10^{-5}[/tex]

Formula to calculate pH is as follows.

[tex]pH = -log [H^{+}][/tex]

Substitute the values into above formula as follows.

[tex]pH = -log [H^{+}]\\= - log (3.2 \times 10^{-5})\\= 4.49[/tex]

Thus, we can conclude that the pH of 0.10 M [tex]Cu(NO_{3})_{2}(aq)[/tex] is 4.49.

Answer:

The partial pressure will be "100 torr".

Explanation:

Given:

[tex]P_{Ar} = 300 \ torr[/tex]

By assuming Ar and Ne having 50 gm each, we get

mol of Ne = [tex]\frac{50}{20}[/tex]

                = [tex]2.5 \ mol[/tex]

mol of Ar = [tex]\frac{50}{40}[/tex]

               = [tex]1.25 \ mol[/tex]

now,

[tex]n_T= mol.A_r+mol.N_e[/tex]

     [tex]=1.25+2.5[/tex]

     [tex]=3.75[/tex]

then,

[tex]X_{Ar}=\frac{n_{Ar}}{n_T}[/tex]

       [tex]=\frac{1.25}{3.75}[/tex]

       [tex]=0.33[/tex]

hence,

The partial pressure of Ar will be:

⇒ [tex]P_{Ar} = P_T\times X_{AT}[/tex]

By substituting the values, we get

           [tex]=300\times 0.33[/tex]

           [tex]=100 \ torr[/tex]

The partial pressure of Ar in the mixture is 99.9 torr

Let the mass of both gas be 10 g

Next, we shall determine mole of each gas.

Mass = 10 g

Molar mass of Ne = 20 g/mol

Mole = mass / molar mass

Mole of Ne = 10 / 20

Mass = 10 g

Molar mass of Ar = 40 g/mol

Mole = mass / molar mass

Mole of Ar = 10 / 40

Next, we shall determine the mole fraction of Ar

Mole of Ne = 0.5 mole

Mole of Ar = 0.25 mole

Total mole = 0.5 + 0.25 = 0.75 mole

[tex]mole \: fraction \: = \frac{mole}{total \: mole} \\ \\ mole \: fraction \: of \:Ar = \frac{0.25}{0.75} \\ \\ mole \: fraction \: of \:Ar = 0.333 \\ \\ [/tex]

Finally, we shall determine the partial pressure of Ar

Mole fraction of Ar = 0.333

Total pressure = 300 torr

Partial pressure = mole fraction × total pressure

Partial pressure of Ar = 0.333 × 300

Learn more on partial pressure: https://brainly.com/question/15577259