Answer:
<h2>225 g</h2>
Explanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volume
From the question we have
mass = 0.9 × 250
We have the final answer as
<h3>225 g</h3>
Hope this helps you
Answer:
Using the periodic table of the elements to find atomic weights, we find that hydrogen has an atomic weight of 1, and oxygen's is 16. In order to calculate the molecular weight of one water molecule, we add the contributions from each atom; that is, 2(1) + 1(16) = 18 grams/mole.
If,105.5mg sample of a white substance, suspected of being cocaine (C17H21NO4), forms 279.3mg of CO2 and 66.46mg of water on combustion, then we can conclude that the white solid is cocaine.
<h3>Types of Cocaine:</h3>
1. Pure Cocaine :
- Pure cocaine is type of crystalline powder which is derived from the leaves of the coca plant.
- Pure cocaine are very rare in the United States of America.
The product is often passes with the help of the supply chain.
2.Crack Cocaine :
- Crack cocaine are small in size and is a kind of rocky material.
- Depending upon it's purity they varies in color.
- Crack cocaine is generally used for smoking.
- it is also known as freebase cocaine.
3. Synthetic Cocaine :
- Synthetic forms of cocaine (also called as fake cocaine) are generally used as medicine in local areas.
- This product is looks like powdered material or crack cocaine.
4.Black Cocaine :
- Black cocaine is a chemically an another version of cocaine that is used to evade detection in body.
- It is usually a combination of cocaine, charcoal and some other chemicals.
- Black cocaine are not commonly used.
<h3> What is Combustion reaction?</h3>
A combustion reaction is a type of chemical reaction in which generally a fuel undergoes an oxidation by the reaction with the help of an oxidizing agent, which ,results in release of energy.
- it is generally an exothermic process.
- It reacts between oxidents and fuels.
- Solid fuels such as coal and wood are generally undergoes an endothermal pyrolysis.
- It results in the creation of fuels.
- The combustion of that types of gaseous fuels is generally used to provide the heat required which is required to accelerate more combustion.
Thus from the above conclusion we can say that, If,105.5mg sample of a white substance, suspected of being cocaine (C17H21NO4), forms 279.3mg of CO2 and 66.46mg of water on combustion, then we can conclude that the white solid is cocaine.
Learn more about Cocaine here: brainly.com/question/944545
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Answer : The Lewis-dot structure of 
is shown below.
Explanation :
Lewis-dot structure : It shows the bonding between the atoms of a molecule and it also shows the unpaired electrons present in the molecule.
In the Lewis-dot structure the valance electrons are shown by 'dot'.
The given molecule is,
As we know that carbon has '4' valence electrons, hydrogen has '1' valence electron, nitrogen has '5' valence electrons and oxygen has '6' valence electrons.
Therefore, the total number of valence electrons in = 4 + 3(1) + 5 + 2(6) = 24
According to Lewis-dot structure, there are 14 number of bonding electrons and 10 number of non-bonding electrons.
Now we have to determine the formal charge for each atom.
Formula for formal charge :
Hence, the Lewis-dot structure of is shown below.
