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3 years ago

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]3 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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Only positive ions have a charge. true or false?

Elis [28]

Answer:

true

Explanation:

5 0

2 years ago

What is the vapor pressure of CS2CS2 in mmHgmmHg at 26.5 ∘C∘C? Carbon disulfide, CS2CS2, has PvapPvap = 100 mmHgmmHg at −−5.1 ∘C

Digiron [165]

Answer: 26.5 mm Hg

Explanation:

The vapor pressure is determined by Clausius Clapeyron equation:

$ln(\frac{P_2}{P_1})=\frac{\Delta H_{vap}}{R}(\frac{1}{T_1}-\frac{1}{T_2})$

where,

$P_1$ = initial pressure at $26.5^oC$ = ?

$P_2$ = final pressure at $-5.1^oC$ = 100 mm Hg

= enthalpy of vaporisation = 28.0 kJ/mol =28000 J/mol

R = gas constant = 8.314 J/mole.K

$T_1$ = initial temperature = $26.5^oC=273+26.5=299.5K$

$T_2$ = final temperature = $-5.1^oC=273+(-5.1)=267.9K$

Now put all the given values in this formula, we get

$\log (\frac{P_1}{100})=\frac{28000}{2.303\times 8.314J/mole.K}[\frac{1}{299.5}-\frac{1}{267.9}]$

$\log (\frac{P_1}{100})=-0.576$

$\frac{P_1}{100}=0.265$

$P_1=26.5mmHg$

Thus the vapor pressure of $CS_2CS_2$ in mmHg at 26.5 ∘C is 26.5

7 0

3 years ago

please help me understand genetic engineering and if it is good or bad! please make it detailed i need help on my essay

Papessa [141]

Thanks for using Brainly. You’re always welcome to ask questions here.

Genetic engineering would be DNA from another organism and combining it with another DNA. It’s also used by scientists to study these types of things.

7 0

2 years ago

5. Which quantities must be conserved in all chemical reactions?

sergey [27]

A force of attraction that holds atom together
<span>When atoms react they form a chemical bond which is defined as a force of attraction that holds atom together. A force of attraction is defined as a kind of force that draws two or more objects together regardless of distance. There are two major categories of forces of attraction, one is intramolecular and intermolecular. Intramolecular forces is the presence of forces in atoms internally. While intermolecular is the force by which the force that is existent in two or more elements. </span>

3 0

2 years ago

Read 2 more answers

A chamber with a fixed volume is shown above. The temperature of the gas inside the chamber before heating is 25.2 C and it’s pr

rusak2 [61]

Answer:

Explanation:

Given parameters:

Initial temperature T₁ = 25.2°C = 25.2 + 273 = 298.2K

Initial pressure = P₁ = 0.6atm

Final temperature = 72.4°C = 72.4 + 273 = 345.4K

Unknown:

Final pressure = ?

Solution:

To solve this problem, we use an adaption of the combined gas law where the volume gas is fixed. This simplification results into:

$\frac{P_{1} }{T_{1} } = \frac{P_{2} }{T_{2} }$

where P and T are temperatures, 1 and 2 are initial and final temperatures.

Input the parameters and solve;

$\frac{0.6}{298.2} = \frac{P_{2} }{345.4}$

P₂ = 0.7atm

3 0

3 years ago