Answer:
balanced;
unbalanced;
unbalanced;
balanced;
Explanation:
CaO + 3C → CaC2 + CO //all elements are balanced
Na + H2O → 2NaOH + H2 //Na is not balanced on the left
4Fe + O2 → 2Fe2O3 //O is not balanced on the left
2Mg + O2 → 2MgO //left is equal to right, balanced
Answer:
particle size analysis, particle size measurement, or simply particle sizing is the collective name of the technical procedures, or laboratory techniques which determines the size range, and/or the average, or mean size of the particles in a powder or liquid sample.
Explanation:
The substance whose Lewis structure shows three covalent bonds is Nitrogen gas molecule.
<h3>What is Lewis structure?</h3>
Lewis structure is a dot structure which gives idea about the number of valence electrons that are involved in the bonding within the molecule.
Lewis dot structure of nitrogen gas will be expressed as in the attached image, where between two nitrogen atoms triple bond is present. That triple bond is formed by the sharing of electrons and known as covalent bonds.
Hence in nitrogen gas molecule three covalent bonds is present.
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Answer:
d, 40 dm3.
Explanation:
According to Avogadro's law, the mole ratio of chemicals in a reaction is equal to the ratio of volumes of chemicals reacted (for gas).
From the equation, the mole ratio of N2 : H2 : NH3 = 1 : 3 : 2, meaning 1 mole of N2 reacts completely with 3 moles of H2 to give 2 moles of NH3, the ratio of volume required is also equal to 1 : 3 : 2.
Considering both N2 and H2 have 30dm3 of volume, but 1 mole of N2 reacts completely with 3 moles of H2, so we can see H2 is limiting while N2 is in excess. Using the ratio, we can deduce that 10dm3 equals to 1 in ratio (because 3 moles ratio = 30dm3).
With that being said, all H2 has reacted, meaning there's no volume of H2 left. 2 moles of NH3 is produced, meaning the volume of NH3 produced = 10 x 2 = 20 dm3. (using the ratio again)
1 mole of N2 has reacted, meaning from the 30dm3, only 10 dm3 has reacted. This also indicate that 20 dm3 of N2 has not been reacted.
So at the end, the mixture contains 20dm3 of NH3, and 20 dm3 of unreacted N2. Hence, the answer is d, 40 dm3.