Answer: they both contain the same metal(calcium)
Explanation: calcium burns with a characteristic orange color.
Answer:
Explanation:
A foam coffe cup is considered a perfectly insulated system: heat energy is not exchanged with the surroundings.
Under that assumption, the heat released by the chemical reaction is equal to the heat absorbed by the system.
1. Heat absorbed by the system:
Use the equation Heat = Q = m × C × ΔT, with:
- m = 126 g (the amount of solution produced)
- C = specific heat of pure water = 4.186 J/gºC
- ΔT = increase of temperature = 24.70 ºC - 21.00ºC = 3.70ºC
Q = 126g × 4.186J/gºC × 3.70ºC = 1,951.5J
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<em><u>2. Enthalpy of the reaction</u></em>
The enthalpy must be reported in kJ/mol.
Then, convert juoles to kilojoules, dividing by 1,000; and divide by 2.00 moles, which is the amount of compound that reacted:
- ΔHrxn = 1,951.5J × (1kJ / 1,000J) × (1 / 2mol) ≈ 0.9758 kJ/mol
Round to <em>3 significant figures</em>: 0.976 kJ/mol
<span>A metal is one which ionizes easily and gives electrons whencompared to other elements.
So it should have a lower ionization energy.
Hence we would expect element 2 to be a metal.</span>
Answer:
Unbalanced
Explanation:
The reactants side says 2Na. This means there should also be 2Na on the product's side. However, there is only 1 Na there. Therefore, the chemical equations are unbalanced.
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Answer:
1.40 M [OH⁻]
Explanation:
This compound dissociates into 3 ions, but since we are asked about [OH⁻], it's only 2. Therefore, multiply the molarity of the solution by the number of ions that [OH⁻] dissociates into:
2 × 0.70 M = 1.40 M
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