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Which is evidence that a chemical reaction has likely occurred?
a liquid slowly losing volume
the formation of a precipitate
boiling water releasing steam
a change in the shape of a solid

Answer:

La respuesta correcta es la opción A.

Explicación:

La densidad del corcho es 0.95g / cm3 por lo que se hundirá en la solución de acetona porque el corcho es más denso que la solución de acetona mientras que por otro lado, el corcho flotará en otros dos líquidos porque la densidad del corcho es menor que en otros dos líquidos o, en otras palabras, los dos líquidos son más densos que el corcho, por eso el corcho flotará en estos dos líquidos.

Answer:

See explanation

Explanation:

Let the equation of dissolution be;

AB2(s) ⇄A(aq) + 2S

Hence;

Ksp = [A] [2s]^2

Let the concentration of the species be s

Ksp= s × (2s)^2

Ksp= 4s^3

Since s= 5mol/dm^3

Ksp = 4(5mol/dm^3)^3

Ksp = 500 mol^2dm^-6

Answer:

4000mL

Explanation:

Using the combined gas law equation;

P1V1/T1 = P2V2/T2

Where;

P1 = initial pressure (atm)

P2 = final pressure (atm)

V1 = initial volume (mL)

V2 = final volume (mL)

T1 = initial temperature (K)

T2 = final temperature (K)

According to the information given in this question:

V1 = 1000mL

T1 = 20K

P1 = 1.0atm

V2 = ?

P2 = 0.5atm

T2 = 40K

Using P1V1/T1 = P2V2/T2

1 × 1000/20 = 0.5 × V2/40

1000/20 = 0.5V2/40

50 = 0.5V2/40

50 × 40 = 0.5V2

2000 = 0.5V2

V2 = 2000/0.5

V2 = 4000mL

Answer:

mass (g) needed = 710.2 grams Na₂SO₄(s)

Explanation:

Needed is 2.5 Liters of 2.0M Na₂SO₄; formula wt Na₂SO₄ = 142.04g/mol.

mass (grams) of Na₂SO₄(s) = Molarity needed x Volume needed in Liters x Formula Wt of solute

mass (grams) of Na₂SO₄(s) = (2.5L)(2.0M)(142.04g/mol) = 710.2 grams Na₂SO₄(s)

Mixing: Transfer 710.4 grams Na₂SO₄ into mixing vessel and add water-solvent up to but not to exceed 2.5 Liters total volume. Mix until dissolved.

Gives 2.5 Liters of 2.0M Na₂SO₄(aq) solution.

Answer:

Hydroxyl

Explanation:

A P E X

The type of fingerprint found at the crime scene in this scenario is referred to as plastic.

This is the of fingerprint which is three dimensional and can be easily seen with the human eye.

Plastic fingerprint can be made by pressing the finger on substances such as wax, paint etc.

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Answer:

the answer would be molded I believe.

choices are Latent,patent, inadmissible molded,trace.

Answer:

This question is incomplete, the gravitational potential energy is 2.65 x 10^5 J

mass of the boulder = 866.7g

Explanation:

Potential energy (P.E) refers to the energy due to the position of a body. It can be calculated as follows:

P.E = m × g × h

Where;

m = mass of substance (g)

g = acceleration due to gravity (m/s²)

h = height (m)

According to the information provided in this question,

h = 31.2 m

g = 9.8m/s²

m = ?

P.E = 2.65 x 10^5 J

Using P.E = m × g × h

2.65 x 10^5 = m × 9.8 × 31.2

2.65 x 10^5 = 305.76m

265000 = 305.76m

m = 265000 ÷ 305.76

m = 866.69

mass of the boulder = 866.7g

Answer: The given compounds are arranged in order of increasing entropy (S) as [tex]CH_{3}OH(s) < CH_{3}OH(l) < CH_{3}CH_{2}OH < CH_{3}OH(g)[/tex]

Explanation:

The degree of randomness present in a substance is called entropy.

This means that more is the number of molecules weakly held together and rapidly moving from one place to another more will be its entropy.

In solids, the molecules are held together strongly with each other. So, they will have least entropy.

In liquids, the molecules are a little loosely held together. So, they have more entropy than a solid substance.

In gases, the molecules are held by weak forces due to which they move rapidly from one place to another. Hence, gases have high entropy as compared to solids and liquids.

Also, more is the molecular mass of a gas less will be its rate of effusion. Hence, less will be its entropy.

[tex]Rate of effusion \propto \frac{1}{\sqrt{M}}[/tex]

where,

M = molecular mass

Thus, we can conclude that given compounds are arranged in order of increasing entropy (S) as [tex]CH_{3}OH(s) < CH_{3}OH(l) < CH_{3}CH_{2}OH < CH_{3}OH(g)[/tex]

gao yin sheng, zhong yin sheng and the other shengs

Answer:

protons because they have the most positive charge

Answer:

Here's your answer

Explanation:

When we insert a burning matchstick near the mouth of gas jar the matchstick burns with a pop sound and produces a blue flame. This proves that the gas collected is hydrogen.

hope it helps

Answer:

[tex]{ \tt{let \: the \: oxidation \: state \: be \: x}} \\ { \bf{x + sulphate \: ion+ water = overall \: charge}} \\ \\ \\ { \tt{x + ( - 2) + 0 = 0}} \\ \\ { \tt{x = + 2}} \\ { \tt{oxidation \: state = + 2}}[/tex]

Answer:

PIEASE E first write question

Answer:

45673

Explanation:

Answer:

Answer is A... Melting and freezing

Answer:

e) 5

Explanation:

Because it's H

Answer:

???what metal????????????

Answer:

It is alkyne

Explanation:

Answer:

3.85 × 10²³ molecules CO

General Formulas and Concepts:

Atomic Structure

Stoichiometry

Explanation:

Step 1: Define

Identify

[Given] 17.9 g CO

[Solve] molecules CO

Step 2: Identify Conversions

Avogadro's Number

[PT] Molar Mass of C: 12.01 g/mol

[PT] Molar Mass of O: 16.00 g/mol

Molar Mass of CO: 12.01 + 16.00 = 28.01 g/mol

Step 3: Convert

Step 4: Check

Follow sig fig rules and round. We are given 3 sig figs.

3.8484 × 10²³ molecules CO ≈ 3.85 × 10²³ molecules CO

Answer:

JWBVH

Explanation:

NWSBWHSBHS

Answer:

Answer:

Don't plagiarize here.

Explanation:

Your online teacher knows that you are looking here for the answer!!!!

Answer:

Give an example of each of the following chemical changes.

(a) A photochemical reaction involving

(i) silver salt

(ii) water

(b) A reaction involving

(i) blue solution

(ii) formation of dirty green precipitate

(c) Two gases combine to form white solid.

(d) A reaction where colour change is noticed.​

Explanation:

a) A photochemical reaction involving  silver salt is used in black and white photography.

AgCl breaks down and converts into Ag during this photochemical reaction.

(ii) Photochemicalreaction involving water takes place in plants during the photosynthesis process.

Plants prepare food(carbohydrate) by using sunlight water and CO2 gas.

(b) A reaction involving

(i) blue solution:

For example reaction of copper sulfate solution with an iron nail.

When an iron nail is placed in CuSO4 blue color solution, then it changes to green color and reddish-brown solid deposits at the bottom of the container.

(ii) Reaction of ferrous sulfate with NaOH forms a dirty green precipitate of ferrous hydroxide.

(C) Two gases combine and form a white solid:

For example when HCl gas reacts with ammonia gas, then a white solid of ammonium chloride will be formed.

(d)  A reaction where the color change is noticed.:

When an iron nail is placed in CuSO4 blue color solution, then it changes to green color and reddish-brown solid deposits at the bottom of the container.

Answer:

Enthalpy and entropy. ... What would happen to the entropy in the reaction 2O3(g) 3O2(g)? It increases

What would happen to the entropy in the reaction 2O3(g) --> 3O2(g)?

It increases.

Answer: NH3 (g) would be considered a base because it is a proton acceptor.

Explanation: at the end of the system, NH3 (g) turns into NH4+ (aq) which means it has accepted a hydrogen ion.

According to Bronsted- Lowry concept, bases are proton acceptors. Here, NH₃ is accepting a proton from HSO₄⁻. Hence, NH₃ is a base and option B is correct.

There are various concepts to define acids and bases. According to Bronsted - Lowry concept, acids are proton donors and bases are proton acceptors.

Acids forms their conjugate base by donating a proton and bases form their conjugate acid by accepting the proton from acid. Here, HSO₄⁻ acts as the acid to donate electron to ammonia.

Hence, NH₃ acts as the base to accept the proton from the acid and forms its conjugate acid NH₄⁺ (ammonium ion). Therefore, option B describes the action of NH₃.

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Your complete question is given below:

Answer: The final temperature will be [tex]23^oC[/tex]

Explanation:

Calculating the heat released or absorbed for the process:

[tex]q=m\times C\times (T_2-T_1)[/tex]

In a system, the total amount of heat released is equal to the total amount of heat absorbed.

[tex]q_1=-q_2[/tex]

    OR

[tex]m_1\times C_1\times (T_f-T_1)=-m_2\times C_2\times (T_f-T_2)[/tex]           ......(1)

where,

[tex]C_1[/tex] = specific heat of aluminium = [tex]0.21 Cal/g^oC[/tex]

[tex]C_2[/tex] = heat capacity of water = [tex]1Cal/g^oC[/tex]

[tex]m_1[/tex] = mass of aluminium = 30. g

[tex]m_2[/tex] = mass of water = 50. g

[tex]T_f[/tex] = final temperature of the system = ?

[tex]T_1[/tex] = initial temperature of aluminium = [tex]40.^oC[/tex]

[tex]T_2[/tex] = initial temperature of the water = [tex]21.^oC[/tex]

Putting values in equation 1, we get:

[tex]30\times 0.21\times (T_f-40)=-50\times 1\times (T_f-21)\\\\56.3T_f=1302\\\\T_f=\frac{1302}{56.3}=23.13^oC=23^oC[/tex]

Hence, the final temperature will be [tex]23^oC[/tex]

The question is incomplete, the complete question is:

Consider the reaction:

[tex]2NOCl\rightleftharpoons 2NO+Cl_2[/tex]

At equilibrium, the concentrations are as follows. [NOCl] = 1.4 × 10–2 M [NO] = 1.2 × 10–3 M [Cl2] = 2.2 × 10–3 M What is the value of Keq for the reaction expressed in scientific notation?

A) 1.6 × 10–5

B) 6.2 × 10–4

C) 6.2 × 10+4

D) 1.6 × 10+5

Answer: The correct option is A) [tex]1.6\times 10^{-5}[/tex]

Explanation:

The equilibrium constant is defined as the ratio of the concentration of products to the concentration of reactants raised to the power of the stoichiometric coefficient of each. It is represented by the term [tex]K_{eq}[/tex]

For the given chemical equation:

[tex]2NOCl\rightleftharpoons 2NO+Cl_2[/tex]

The expression for equilibrium constant will be:

[tex]K_{eq}=\frac{[NO]^2}{[Cl_2][NOCl]^2}[/tex]

Given values:

[tex][NO]=1.2\times 10^{-3}M[/tex]

[tex][Cl_2]=2.2\times 10^{-3}M[/tex]

[tex][NOCl]=1.4\times 10^{-2}M[/tex]

Putting values in above expression, we get:

[tex]K_{eq}=\frac{(1.2\times 10^{-3})^2\times (2.2\times 10^{-3})}{(1.4\times 10^{-2})^2}\\\\K_{eq}=1.6\times 10^{-5}[/tex]

Hence, the correct option is A) [tex]1.6\times 10^{-5}[/tex]

Answer: Because this does not dissolve in water - it forms a barrier on the surface of the unreacted CaCO3 which prevents any further reaction. A small volume of CO2 is produced , but this stops after a short time . Conclusion: H2SO4 cannot be used with CaCO3 to produce CO2 gas .

Explanation: