Answer:
Because electron mass is so insignificant compared to proton and neutron mass that it can be ignored.
Explanation:
Answer: option <span>B.The total mass of A and C, which are carbon and oxygen, is equal to the mass of B, which is carbon dioxide.
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Explanation:
1) The combustion of carbon is represented by the chemical equation:
C + O₂ → CO₂
2) The law of conservation of mass states that the mass of the products is equal to the mass of the reactants.
3) The reactants are C and O₂, while the product is CO₂.
4) The masses given are: A: 12 g, B: 44 g, and C: 32 g
Then, 12g + 32 g = 44 g, this is A + C = B.
Then, B represents the product, which is CO₂, whose molar mass is 44 g/mol.
Since, the molar mass of C is 12 g/mol, it is A; and since the molar mass of O₂ is 32, it is C.
Therefore, the answer is the option B.
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Answer:
2914 J
Explanation:
Step 1: Given data
- Mass of the copper tubing (m): 665.0 g
- Initial temperature: 15.71 °C
- Final temperature: 27.09 °C
- Specific heat of copper (c): 0.3850 J/g.°C
Step 2: Calculate the temperature change
ΔT = 27.09 °C - 15.71 °C = 11.38 °C
Step 3: Calculate the energy required (Q)
We will use the following expression.
Q = c × m × ΔT
Q = 0.3850 J/g.°C × 665.0 g × 11.38 °C
Q = 2914 J
At room temperature oxygen, 
is present in the gas phase.
A gas is defined as a substance which is characterized by the rapidly movement of molecules which are widely separated. The shape and volume of gas is not definite that is they take on the shape of the container in which it is placed. The gas molecules have minimum inter-nuclear attractions and thus have high kinetic energy.
Thus, the sentences that describes oxygen at room temperature are:
- It has no definite volume and takes the shape of its container.
- Its particles move fast enough to overcome the attraction between them.
- It has more energy than it would be at a cooler temperature as the kinetic energy is directly proportional to the temperature that is kinetic energy increases on increasing the temperature.
Correct answers are:
- Solids can diffuse in liquids. Think of a sugar cube sitting at the bottom of a cup of tea.
- Liquids can diffuse in liquids. Think of a drop of food colouring in water
- It is the process of intermingling atoms from one substance into another.
The other answers are <em>incorrect</em> because:
- Gas molecules are far apart and diffuse rapidly.
- A solid can diffuse into another solid. Pure lead can diffuse into gold, and pure gold can diffuse into lead.
