Cho muối X vào dd NaOH, đun nóng, thu được một chất khí làm xanh giấy quỳ ẩm. Chất nào sau đây thỏa mãn tính chất của X?

What is the charge on an ion that has an atomic number of 16 and contains 14e-?

lora16 [44]

The answer would be 2+ since the atomic number represents how many protons are in the element. In this case, there are 16 protons, but only 14 electrons, which means there are an additional 2 protons, hence the 2+ charge on the ion.

3 0

2 years ago

Which of the following reactions have a positive ΔSrxn? Check all that apply.

PolarNik [594]

Answer:

The reactions that have a positive ΔS rxn are the first and the fourth choices:

2A(g) + B(s) → 3C(g)

2A(g) + 2B(g) → 5C(g)

Explanation:

ΔS rxn is the change of entropy of the chemical reaction.

ΔS rxn = S after reaction - S before reaction.

Therefore, a positive ΔS rxn means that the entropy after the reaction is greater than the entropy before the reaction.

You may use some assumptions to predict whether a reaction will lead an increase or decrease of the entropy.

First, assume that all the non-shown conditions, such as temperature and pressure, are constant.

Under that assumption, and from the meaning of entropy as a measure of the disorder or randomness of a system you can predict the sign of the change of entropy.

2A(g) + B(s) → 3C(g)

1) The solid compounds, B(s) in this case, are very ordered and so they have low entropy.

2) Gas molecules are highly disordered (scattered), and the greater the number of molecules of the gas the larger the entropy, S).

Hence, since the product side shows 3 gas molecules and the reactant side shows 2 gas molecules and 1 solid molecule, you predict that the products have a larger entropy than the reactants, meaning an increase in entropy: ΔS rxn is positive.

2A(g) + B(g) → C(g)

Using the same reasoning, 3 gas molecules in the reactant side have more entropy than 1 molecule in the product side, and so the reaction leads to a decrease in the entropy: ΔS rxn is negative

A(g) + B(g) → C(g)

Again, 2 gas molecules in the reactant side have more entropy than 1 molecule in the product side, and so the reaction leads to a decrease in the entropy: ΔS rxn is negative

2A(g) + 2B(g) → 5C(g)

With the same reasoing, 5 molecules in the product side, lets you predict that will have more entropy than 4 molecules in the reactant side, and, the entropy will increase: ΔS rxn is positive.

6 0

3 years ago

What would be the best indicator for titrating the weak base sodium bicarbonate using hcl titrant?

BabaBlast [244]

The methyl orange would be the best indicator for titrating the weak base sodium bicarbonate using HCl titrant

When weak base is titrated with strong acid then , then solution is slightly acidic at end point . If weak acid is titrated with strong base then , the solution is slightly basic because salt formed will hydrolyzed to a certain extent .

In acid base titration at the end point the amount of the acid becomes chemically equivalent to the amount of the base present .The methyl orange would be the best indicator for titrating the weak base with strong acid .

To learn more about weak base please click here ,

brainly.com/question/19340043

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6 0

1 year ago

Nitrogen dioxide (NO2) cannot be obtained in a pure form in the gas phase because it exists as a mixture of NO2 and N2O4. At 16°

Pavel [41]

Answer:

PNO₂ = 0.49 atm

PN₂O₄ = 0.45 atm

Explanation:

Let's begin with the equation of ideal gas, and derivate from it an equation that involves the density (ρ = m/V).

PV = nRT

n = m/M (m is the mass, and M the molar mass)

$PV = \frac{m}{M}RT$

$PxM = \frac{m}{V}RT$

PxM = ρRT

ρ = PxM/RT

With the density of the gas mixture, we can calculate the average of molar mass (Mavg), with the constant of the gases R = 0.082 atm.L/mol.K, and T = 16 + 273 = 289 K

$2.7 = \frac{0.94xMavg}{0.082x289}$