Answer:
Electronegativity in group 1 decreases as we go from Lithium to Francium.
Explanation:
Electronegativity is defined as the tendency of an element to attract an electron pair towards itself.
In a group generally this tendency decreases from top to bottom as the size of the atom increases and hence the positive nucleus get far from the outer orbital.
In the same way group 1 elements i.e. from Lithium to Francium electronegativity decreases.
The larger the piece the longer it will take to break down. This is because it has more mass that needs to be broken down.
Answer:
480 g of oxygen.
Explanation:
C3H8 + 5O2 ---> 3CO2 + 4H2O
Using the molar masses:
3*12 + 6*16 g of CO2 were formed from 10*16 g O2
132g g CO2 from 160 g O2
1g CO2 from (160/132) g O2
396 g from (160/132) * 396
= 480 g of oxygen.
<h3>
Answer:</h3>
63 years
Eighth
The number of half lives
<h3>
Explanation:</h3>
It will take 63 years for half of the sample to decay
In 189 years, eighth of the sample will be left
Scientists can figure out how old a sample is by multiplying the number of half lives by the length of the half life.
Half life is the time taken by a radioactive sample to decay to half of the original amount.
Therefore, for a radioactive element with a half-life of 63 years, it will take 63 years for the sample to decay to half of the original amount.
After 189 years, only an eighth of the sample will be left.
That is, 189 years is equivalent to 3 half-lives
Therefore, if the original amount is 1, then;
1 → 0.5 → 0.25 → 0.125
Thus, scientists can figure out how old a sample is by multiplying the number of half lives by the length of the half life.
