<span>Molality(m) or molal concentration is a measure
of concentration and it refers to amount of substance in a specified amount of
mass of the solvent. Used unit for molality is mol/kg which is also
sometimes denoted as 1 molal. It is equal to the moles of solute (the substance
being dissolved) divided by the kilograms of solvent (the substance used to
dissolve).</span>
Molarity(M) or molar concentration is also a
measure of concentration and represents the amount of substance per unit volume
of solution(number of moles per litre of solution. Used unit for molarity is
mol/L or M. A solution with a concentration of 1 mol/L is equivalent to 1 molar
(1 M).
Molality is preferred when
the temperature of the solution varies, because it does not depend on
temperature, (neither number of moles of solute nor mass of solvent will be affected
by changes of temperature), while molarity changes as temperature changes(volume
of solution changes as temperature changes).
Assuming there is excess acid, the equation for the reaction is Zn + 2HCl -> ZnCl2 + H2.
Mols of zinc = 20/65 (mass/relative atomic mass)
Ratio of Zn : ZnCl2 = 1 : 1
Hence mols of Zinc = mols of Zinc chloride
Mass of ZnCl2 = (20/65)(65+71)
= 41.8g
Answer: The child isotope has an atomic mass of 206.
Explanation:
Alpha decay : When a larger nuclei decays into smaller nuclei by releasing alpha particle. In this process, the mass number and atomic number is reduced by 4 and 2 units respectively.
General representation of an element is given as: 
where,
Z represents Atomic number
A represents Mass number
X represents the symbol of an element
General representation of alpha decay :
Answer:
Please find the structure of the hydrocarbon in the attachment section and details on how to draw it in the explanation section.
Explanation:
Heptane is a member of the alkane group, which has a general formula of CnH2n+2. If n in heptane is 7, this means that the chemical formula for heptane will be C7H16 i.e.
= C7H2(7) + 2
= C7H14+2
= C7H16
C7H16 is the chemical formula for heptane, which is a linear hydrocarbon with 7 carbon atoms and 16 hydrogen atoms. However, in the name of the hydrocarbon compound given in the question: 2,3-dimethylheptane;
- Two methyl groups (CH3) has a substituted two hydrogen atoms specifically at carbon 2 and 3 respectively. Therefore, the new chemical formula of 2,3-dimethylheptane will be: C7H14(CH3)2
Please find the structural formula of the compound; 2,3-dimethylheptane as an attachment.
Answer:
Empirical Formula = NH₄NO₃ (Ammonium Nitrate)
Solution:
Step 1: Calculate Moles of each Element;
Moles of N = %N ÷ At.Mass of N
Moles of N = 35.0 ÷ 14
Moles of N = 2.5 mol
Moles of O = %O ÷ At.Mass of O
Moles of O = 59.96 ÷ 16
Moles of O = 3.7475 mol
Moles of H = [100% - (%N + %O)] ÷ At.Mass of H
Moles of H = [100% - (35.0 + 59.96)] ÷ 1.008
Moles of H = [100% - 94.96] ÷ 1.008
Moles of H = 5.04 ÷ 1.008
Moles of H = 5 mol
Step 2: Find out mole ratio and simplify it;
N H O
2.5 5 3.7475
2.5/2.5 5/2.5 3.7475/2.5
1 2 1.5
Multiply Mole Ratio by 2,
2 4 3
Result:
Empirical Formula = N₂H₄O₃
Or,
Empirical Formula = NH₄NO₃
This empirical formula is also a Molecular Formula for Ammonium Nitrate a well known Fertilizer and often misused in the formation of Explosives.
