This is an acid – base reaction and this always result a salt and water
in a neutralization reaction. <span>
The salt that is formed will be calcium bromide (calcium
is located in group 2 so calcium bromide has a formula of CaBr2)
so essentially we got:
HBr + Ca(OH)2 ------> CaBr2 + H2O </span>
balancing the elements: <span>
<span>2HBr(aq) + Ca(OH)2(aq) --------> CaBr2(aq) +
2H2O(l)</span></span>
The much of the sample that would remain unchanged after 140 seconds is 2.813 g
Explanation
Half life is time taken for the quantity to reduce to half its original value.
if the half life for Scandium is 35 sec, then the number of half life in 140 seconds
=140 sec/ 35 s = 4 half life
Therefore 45 g after first half life = 45 x1/2 =22.5 g
22.5 g after second half life = 22.5 x 1/2 =11.25 g
11.25 g after third half life = 11.25 x 1/2 = 5.625 g
5.625 after fourth half life = 5.625 x 1/2 = 2.813
therefore 2.813 g of Scandium 47 remains unchanged.
The total number of atoms in 7.10g of chlorine is 1.204 × 10²³atoms.
HOW TO CALCULATE NUMBER OF ATOMS:
- The number of atoms in a substance can be calculated by multiplying the number of moles in that substance by Avogadro's number as follows:
- no. of atoms = no. of moles × 6.02 × 10²³ mol-¹
- The number of moles in 7.10g of Cl is calculated as follows:
no. of moles = mass ÷ molar mass
no. of moles = 7.10g ÷ 35.5g/mol
no. of moles = 0.2mol
no of atoms = 0.2mol × 6.02 × 10²³
no. of atoms = 1.204 × 10²³atoms.
- Therefore, the total number of atoms in 7.10g of chlorine is 1.204 × 10²³atoms.
Learn more: brainly.com/question/15488332?referrer=searchResults
Answer:
pill need to taken for completing dosage of 
mg
Explanation:
Total dosage of medicine to be taken in a day
mg
Total weight of one pill 
mg
Number of pills required is equal to total dosage of medicine divided by the weight of one pill.
Hence,
Number of pills
