Which of the following does not describe elements?

2 answers:

6 0

The statement that does not describe elements would be that they can be separated by a chemical reaction. This is not the case, an element is a pure substance that can't be degraded into any other constituent that would form it. They are building blocks composed by atoms.

shusha [124]2 years ago

3 0

Answer: Option (b) is the correct answer.

Explanation:

Elements are defined as the substance which contain same type of atoms.

An element cannot be divided into simpler substances by any physical or chemical means.

For example, a piece of aluminium will contain only atoms of aluminium.

The periodic table contains all the elements present in nature.

Thus, we can conclude that out of the given options the statement they can be separated by a chemical reaction, does not describe elements.

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A chemical engineer must calculate the maximum safe operating temperature of a high-pressure gas reaction vessel. The vessel is

Inessa05 [86]

Answer:

$T=2.78x10^3 \°C$

Explanation:

Hello,

In this case, considering that the safe temperature may be computed via the ideal gas law as we now the pressure, mass and volume via the dimensions:

$V=\pi r^2 h=\pi *(41.0cm)^2*49.2cm=2.60x10^5cm^3*\frac{1L}{1000cm^3} =260L$

The pressure in atm is:

$P=3.70MPa*\frac{1x10^6Pa}{1MPa} \frac{1atm}{101325Pa} =36.5atm$

And the moles considering the mass and molar mass (66 g/mol) of dinitrogen difluoride (N₂F₂):

$n_{N_2F_2}=2.50kg*\frac{1000g}{1kg}*\frac{1mol}{66g} =37.9mol$

In sich a way, by applying the ideal gas equation, which is not the best assumption but could work as an approximation due to the high temperature, the temperature, with three significant figures, will be:

$T=\frac{PV}{nR}=\frac{36.5Pa*260L}{37.9mol*0.082\frac{atm*L}{mol*K} }\\ \\T=3053.6K-273.15\\\\T=2.78x10^3 \°C$

Best regards.

7 0

1 year ago

Cobalt-60 is produced by a three reaction process involving neutron capture, beta-emission, and neutron capture. The initial rea

Dima020 [189]

Answer : The correct option is, (C) $^{58}\textrm{Fe}$

Explanation :

Neutron capture : In this decay process, an atomic nucleus and one or more number of neutrons collide and combine to form a heavier nucleus. The mass number changes in this process.

The neutron capture equation is represented as,

$_Z^A\textrm{X}+_{0}^1\textrm{n}\rightarrow _{Z}^{A+1}\textrm{X}+\gamma$

(A is the atomic mass number and Z is the atomic number)

Beta emission or beta minus decay : It is a type of decay process, in which a neutrons gets converted to proton, an electron and anti-neutrino. In this the atomic mass number remains same.

The beta minus decay equation is represented as,

$_Z^A\textrm{X}\rightarrow _{Z+1}^A\textrm{Y}+_{-1}^0e$