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Rainbow [258]
3 years ago
8

Give two reasons why the flame test is sometimes invalid

Chemistry
2 answers:
Harlamova29_29 [7]3 years ago
7 0

Answer: 1.A false positive and 2.A false negative.

Explanation:

A false positive the classic example is the contamination of almost any sample with sodium ions which gives an intense yellow line even when the sodium is present as only impurity.

A false negative here sodium ions is the culprit that masks other emissions unless the emissions are resolved spectroscopically rather than simply visually.

zlopas [31]3 years ago
6 0
The two reason behind the invalidity of flame test are false positive and false negative.
while performing the flame test you must have to be accurate otherwise you will get false results may be positive for some element or may be negative in case the element is present. The main reason to get the false positive and false negative is the presence and contamination of sodium.
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What is the formula weight (amu) of the molecule H2O? Use atomic masses of H and O as 1.008 amu and 16.00 amu respectively. Repo
vaieri [72.5K]

Answer:

Formula weight of H₂O molecule is  18.02 amu.

Explanation:

Given data:

Formula weight of H₂O = ?

Atomic mass of H = 1.008 amu

Atomic mass of O = 16.00 amu

Solution:

Formula weight:

"It is the sum of all the atomic weight of atoms present in given formula"

Formula weight of H₂O = 2×1.008 amu + 1×16.00 amu

Formula weight of H₂O = 18.02 amu

Thus, formula weight of H₂O molecule is  18.02 amu.

6 0
3 years ago
1. At room temperature, air is usually a (solid, liquid, gas).​
kirza4 [7]
At room temperature the air is Gas
3 0
2 years ago
If copper carbonate system is heated for too short a time, what will you notice for mass percent of copper be too large or too s
sammy [17]

Answer:

The mass percent of copper as element is the same.

Explanation:

First of all we need the reaction that is presented below:

CuCO_{3 (s)} +Heat → CuO_{(s)} + CO_{2 (g)}

The mass percent of copper (Cu) as element is the same because of during the reaction the element only transform its nature from copper carbonate (CuCO_{3 (s)}) to copper oxide (CuO_{(s)}), the latter is a solid and will remain in the system.

On the other hand, you will note that the global percentage mass will be small because of the reaction produce (CO_{2 (g)}) that is a gas and this one will escape for the system.  

Have a great day!

3 0
3 years ago
When the following reaction comes to equilibrium, will the concentrations of the reactants or products be greater? Does the answ
Nutka1998 [239]

Answer:

At equilibrium, the concentration of the reactants will be greater than the concentration of the products. This does not depend on the initial concentrations of the reactants and products.

Explanation:

The value of Kc gives us an idea of the extent of the reaction. A big Kc (Kc > 1) means that in the equilibrium there are more products than reactants, and the opposite happens for a small Kc (Kc < 1). The equilibrium is reached no matter what the initial concentrations are.

The value of the equilibrium constant is relatively SMALL; therefore, the concentration of reactants will be GREATER THAN the concentration of products. This result is INDEPENDENT OF the initial concentration of the reactants and products.

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3 years ago
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7 0
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