Answer:
Explanation:
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In this case, since this is a system in which the water is heated up and the metal is cooled down in a calorimeter which is not affected by the heat lose-gain process, we can infer that the heat lost by the metal is gained be water, it means that we can write:
Thus, in terms of masses, specific heats and temperatures we can write:
Whereas the equilibrium temperature is the given final temperature of 28.4 °C and we can compute the specific heat of the metal as shown below:
Plugging the values in and since the density of water is 1.00 g/mL so the mass is 80.0g, we obtain:
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Answer: -227 kJ
Explanation:
The balanced chemical reaction is,
The expression for enthalpy change is,
![\Delta H=\sum [n\times \Delta H_f(product)]-\sum [n\times \Delta H_f(reactant)]](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5Csum%20%5Bn%5Ctimes%20%5CDelta%20H_f%28product%29%5D-%5Csum%20%5Bn%5Ctimes%20%5CDelta%20H_f%28reactant%29%5D)
![\Delta H=[(n_{CO_2}\times \Delta H_{CO_2})+ n_{H_2O}\times \Delta H_{H_2O})]-[(n_{C_2H_2}\times \Delta H_{C_2H_2})+(n_{O_2}\times \Delta H_{O_2})]](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5B%28n_%7BCO_2%7D%5Ctimes%20%5CDelta%20H_%7BCO_2%7D%29%2B%20n_%7BH_2O%7D%5Ctimes%20%5CDelta%20H_%7BH_2O%7D%29%5D-%5B%28n_%7BC_2H_2%7D%5Ctimes%20%5CDelta%20H_%7BC_2H_2%7D%29%2B%28n_%7BO_2%7D%5Ctimes%20%5CDelta%20H_%7BO_2%7D%29%5D)
where,
n = number of moles
(as heat of formation of substances in their standard state is zero
Now put all the given values in this expression, we get
![-1255.8=[(2\times -393.5)+(1\times -241.8)]-[(1\times \Delta H_{C_2H_2})+(\frac{5}{2}\times 0)]](https://tex.z-dn.net/?f=-1255.8%3D%5B%282%5Ctimes%20-393.5%29%2B%281%5Ctimes%20-241.8%29%5D-%5B%281%5Ctimes%20%5CDelta%20H_%7BC_2H_2%7D%29%2B%28%5Cfrac%7B5%7D%7B2%7D%5Ctimes%200%29%5D)
![-1255.8=[(-787)+(-241.8)]-[(1\times \Delta H_{C_2H_2})+(0)]](https://tex.z-dn.net/?f=-1255.8%3D%5B%28-787%29%2B%28-241.8%29%5D-%5B%281%5Ctimes%20%5CDelta%20H_%7BC_2H_2%7D%29%2B%280%29%5D)
Therefore, the enthalpy change for 
is -227 kJ.
The question is incomplete, the complete question is;
Zinc and sulfur react to form zinc sulfide by the equation shown below. How many grams of ZnS can be formed when 12.0 g of Zn reacts with 6.50 g of S? (Atomic mass: Zn = 65.38, S = 32.06).
Answer:
17.5 g of ZNS
Explanation:
The equation of the reaction is;
Zn(s) + S(s) ------->ZnS(s)
Number of moles of Zn = 12.0/65.38 = 0.18 moles
Number of moles of S = 6.50/32.06 = 0.20 moles
Hence Zn is the limiting reactant
If 1 mole of Zn yields 1 mole of ZnS
Then 0.18 moles of Zn also yields 0.18 moles of ZnS
Mass of ZnS produced = 0.18 moles * 97.44 g/mol = 17.5 g of ZNS
The earliest idea of the atom is that it is made up of tiny, invisible particles, called the atoms, is believed to have originated from the Greek philosopher Leucippus of Miletus and his student, Democritus of Abdera, around 5th century B.C. However, it wasn't until centuries later that the atomic theory was taken seriously by the society, thanks to the scientist John Dalton by 1808. Hence, the development of the Atomic Theory began until the modern age. Modern scientist has more technological advancements than the early age. Therefore, the modern scientist can view the atom more detailed than before.
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As you go from left to right and down to up on the periodic table, atomic radius decreases. This would make helium the smallest and francium the largest.
