Answer:
d. Sum of product enthalpies minus the sum of reactant enthalpies
Explanation:
The standard enthalpy change of a reaction (ΔH°rxn) can be calculated using the following expression:
ΔH°rxn = ∑n(products) × ΔH°f(products) - ∑n(reactants) × ΔH°f(reactants)
where,
ni are the moles of products and reactants
ΔH°f(i) are the standard enthalpies of formation of products and reactants
The element bromine is not a reddish-brown liquid. Liquid is the substance bromine.
M=DV
M=3.103 g/mL * 19.8 mL = 61.44 g
The amount of the 240 g sample of the radioisotope that will remain after 525 billion years is 7.5 g
<h3>How to the number of half-lives that has elapsed</h3>
- Half-life (t½) = 105 billion years
- Time (t) = 525 billion years
- Number of half-lives (n) = ?
n = t / t½
n = 525 / 105
n = 5
<h3>How to determine the amount remaining</h3>
- Original amount (N₀) = 240 g
- Number of half-lives (n) = 5
- Amount remaining (N) = ?
N = N₀ / 2ⁿ
N = 240 / 2⁵
N = 240 / 32
N = 7.5 g
Learn more about half life:
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Answer:
The atomic numbers of both are 54 while the mass numbers are 131 and 133 respectively.
Explanation:
- The number of protons = Atomic number. So, if the atom has 54 protons and it remained unchanged, then the two types of atoms of this element both have atomic numbers of 54.
- On the other hand, mass number is the sum of protons and neutrons
So, if type 1 has protons = 54 and neutrons = 77: mass number = 54 + 77 = 131
if Type 2 has protons = 54 and neutrons = 79: mass number = 54 + 77 = 133
(Since the possibility of atoms of the same element to have different mass numbers but the same atomic number is called isotopy). The two types of atoms with mass numbers 131 and 133 described are isotopes.
Answer:
Water's heat of vaporization is around 540 cal/g at 100 °C. The same amount of heat is exchanged or released in the phase shift during the condensation of 1 g water vapor to 1 g of water.
Explanation:
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