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3 years ago

Which of the following is the most likely sign that a chemical change has happened?

Chemistry

1 answer:

Dovator [93]3 years ago

4 0

Answer:

The correct option is B) two liquids are mixed at room temperature and a gas forms.

Explanation:

A chemical change can be described as a change which results in the formation of a new substance by the reactants. In the option B, two liquids react to form a new product which is a gas. Hence, it is an example of chemical change.

Other options,like option D, is not a chemical change as by crushing a solid no new product is formed. Option C is also not correct because as when salt dissolves in water, no new product is made.

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b) Si los ácidos nitroso y fluorhídrico están descritos como electrolitos débiles, ¿significa que en la disolución hay moléculas

viva [34]

Los electrolitos son sustancias que se disocian en agua para dar iones.

Generalmente en química, podemos clasificar sustancias como

Electrolitos

No electrolitos

Los electrolitos pueden disociarse en solución para producir iones, pero un no electrolito no puede hacer eso.

Entre los electrolitos hay dos clases;

Electrolitos fuertes

Electrolitos débiles

Los electrolitos fuertes se disocian completamente en solución, mientras que los electrolitos débiles no se disocian completamente en solución.

El hecho de que los electrolitos débiles no se disocien por completo significa que algunas moléculas de la sustancia no se disocian.

Por lo tanto, si los ácidos nitroso y fluorhídrico se describen como electrolitos débiles, esto significa que hay moléculas en la solución que no están disociadas.

Lea más: brainly.com/question/14566383

5 0

2 years ago

A 0.539 g sample of a metal, M, reacts completely with sulfuric acid according to the reaction M(s)+H2SO4(aq)⟶MSO4(aq)+H2(g) A v

Charra [1.4K]

Answer:

The molar mass of the metal is 54.9 g/mol.

Explanation:

When we work with gases collected over water, the total pressure (atmospheric pressure) is equal to the sum of the vapor pressure of water and the pressure of the gas.

Patm = Pwater + PH₂

PH₂ = Patm - Pwater = 1.0079 bar - 0.03167 bar = 0.9762 bar

The pressure of H₂ is:

$0.9762bar.\frac{1atm}{1.013bar} =0.9637atm$

The absolute temperature is:

K = °C + 273 = 25°C + 273 = 298 K

We can calculate the moles of H₂ using the ideal gas equation.

$P.V=n.R.T\\n=\frac{P.V}{R.T} =\frac{0.9637atm \times 0.249L }{(0.08206atm.L/mol.K)\times298K} =9.81 \times 10^{-3} mol$

Let's consider the following balanced equation.

M(s) + H₂SO₄(aq) ⟶ MSO₄(aq) + H₂(g)

The molar ratio of M:H₂ is 1:1. So, 9.81 × 10⁻³ moles of M reacted. The molar mass of the metal is:

$\frac{0.539g}{9.81 \times 10^{-3} mol} =54.9g/mol$

4 0

3 years ago

The sum of the number of proteins and neutrons in an atoms nucleus is its __________ ___________.

otez555 [7]

Answer:

Mass Number

Explanation:

In nuclear physics, the sum of the numbers of protons and neutrons present in the nucleus of an atom.

Please vote brainliest!

8 0

2 years ago

Read 2 more answers

Why is salt water intrusion a big problem in florida?

Schach [20]

Its leading to contaminated drinking water.

7 0

3 years ago

Read 2 more answers

A sample of oxalic acid (a diprotic acid of the formula H2C2O4) is dissolved in enough water to make 1.00 L of solution. A 100.0

OleMash [197]

Answer: The mass of original oxalic acid sample is 6.75 grams

Explanation:

To calculate the concentration of acid, we use the equation given by neutralization reaction:

$n_1M_1V_1=n_2M_2V_2$

where,

$n_1,M_1\text{ and }V_1$ are the n-factor, molarity and volume of acid which is $H_2C_2O_4$

$n_2,M_2\text{ and }V_2$ are the n-factor, molarity and volume of base which is NaOH.

We are given:

$n_1=2\\M_1=?M\\V_1=100.0mL\\n_2=1\\M_2=0.750M\\V_2=20.0mL$

Putting values in above equation, we get:

$2\times M_1\times 100.0=1\times 0.750\times 20.0\\\\M_1=\frac{1\times 0.750\times 20.0}{2\times 100.0}=0.075M$

To calculate the mass of solute, we use the equation used to calculate the molarity of solution:

$\text{Molarity of the solution}=\frac{\text{Mass of solute}}{\text{Molar mass of solute}\times \text{Volume of solution (in L)}}$

Given mass of oxalic acid = ? g

Molar mass of oxalic acid = 90 g/mol

Molarity of solution = 0.075 M

Volume of solution = 1.00 L

Putting values in above equation, we get:

$0.075M=\frac{\text{Mass of oxalic acid}}{90g/mol\times 1L}\\\\\text{Mass of oxalic acid}=(0.075\times 90\times 1)=6.75g$

Hence, the mass of original oxalic acid sample is 6.75 grams

7 0

2 years ago