Answer:
The mass percent of copper as element is the same.
Explanation:
First of all we need the reaction that is presented below:
→ 
The mass percent of copper (Cu) as element is the same because of during the reaction the element only transform its nature from copper carbonate (
) to copper oxide (
), the latter is a solid and will remain in the system.
On the other hand, you will note that the global percentage mass will be small because of the reaction produce (
) that is a gas and this one will escape for the system.
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A. The molecules of solids are close together and compact, liquids are spread out but not too far apart, and gas molecules are really far apart.
B. Increase in temperature causes pressure to go up. Decrease in temperature cause pressure to go down
Instability
Explanation:
Isotopes decays because they are unstable. Stable isotopes do not decay.
- For every atomic nucleus, there is a specific neutron/proton ratio.
- This ratio ensure that a nuclide is stable.
- For example, fluorine F, is 10/9 stable.
- Any nucleus with a neutron/proton combination different from its stability ratio either too many neutrons or too many protons will become unstable.
- Such nuclide will split into one or more other nuclei with the emission of small particles of matter and considerable amount of energy.
Learn more:
Radioactive brainly.com/question/10125168
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Electron structure of sodium:
₁₁Na: 1s²2s²2p⁶3s¹
Answer: 12g
Explanation:
The amount of energy (Q) required to raise the temperature of a substance depends on its Mass (M), specific heat capacity (C) and change in temperature (Φ)
Thus, Q = MCΦ
Given that:
Q = 216 joules
Mass of aluminium = ? (let unknown value be Z)
C = 0.90 JºC-1g-1
Φ = (Final temperature - Initial temperature)
= 35°C - 15°C = 20°C
Then, Q = MCΦ
216 J = Z x 0.90 JºC-1g-1 x 20°C
216 J = Z x 18 J°g-1
Z = (216J/18 J°g-1)
Z = 12g
Thus, the mass of the aluminium is 12grams
