Basic Concepts Of Chem Flashcards
What is matter ?
Matter can be defined as anything that can occupy space and has mass
Explain why gases and solids are completely opposite states while liquids are a intermediate?
The reasons for is this their properties solids are well defined, rigid, compact while gases are loose, unstructured and compressible.
On the other hand liquids are semi defined , free to flow compressible and rigid as the same time
What is the main difference between a compound and mixture?
A compound involves chemical combination of elements while a mixture is a mixing multiple pure substances
How are mass and weight different from each other ?
Mass is the amount of matter in a substance while weight is the amount of gravitational force applied if the body
How many different scales of temperature do we have? Which of these is considered as the SI unit?
There are 3 scales of temperature
1. Fahrenheit scale: can have negative temperature
32-212
F = 9/5(c) +32
2. Celsius scale: can have negative temperature
0-100
3. Kelvin scale: can’t have negative numbers.
273 -373
K = c+273.15
Are accuracy and pression the same or are they different?
Accuracy means the agreement to the true value while pression deals with the closeness of the different measure values
How is the law of definite proportion different Gay Lussac’s of gaseous volume ?
The law of definite proportion is defined taking mass into consideration while Gay Lussac’s law was on the bases of volume of the substance
What does the law of multiple proportion states.
the law of multiple proportion stated that if two elements can combine to form more that 1 compound ten the mass of the element with combines with the fixed mass of the other does so in whole number ratio
What is Avogadro’s law on volume of gases?
equal volume of all gases at the same pressure and temperature should contain the equal number of molecules
What did Dalton propose by his “Atomic theory “?
With the help of his atomic theory Daltons said the following things
1. Matter consist of indivisible atoms
2. atoms of same element have identical properties
3. Chemical reaction involves the rearrangement of atoms
4. Compounds are formed by combination of two or more different types of atoms
Why do we use average atomic mass?
We use average atomic mass due to the existence of multiple isotopes of the same element
How is molecular mass different from formula unit mass?
Formula unit mass is the calculation of mass of ionic compound while molecular mass is used to calculate the mass of the compounds
What was the reason for the introduction of mole concept?
The reason for the existence of the more concept is to make calculation easy 1 mol = 6.022 *10^23 anything also called Na
How can you calculate the number of moles?
No. of moles
- given mass/molar mass
- no. of anything / Na
- Volume at STP/22.4
What is percentage composition?
percentage composition is where we calculate the percent mass of a given element in the compound
mass% =mass of element / mass of compound *100
