Firstly, the density of any substance is represented by the mass (amount of matter) as divided by the volume(amount of space). According to external websites, the mass of a penny is 2.5 grams.However, the volume of a penny is .35cm to the power of 3 (due to the thickness of the penny being extremely minimal.Thus the amount of density is extremely little). Therefore, the density of a penny is 0.875 g/cm cubed (dimensional analysis).As for an invention that could be used, that is possible with the usage of a series of measurements that can both calculate mass and volume and directly allocate that to attain density
Answer:
Planetary orbits are all nearly circular , comet orbits are highly excentric . ... This means that planets stay more or less at the same distance from the sun, while comets travel as far out as beyond Neptune, and can travel as far in as Mercury.
Answer: 31.55 g
Explanation:
- The mass number of Fluoride atom (F) = 18.99 g/mol, so mass number of fluorine gas (F2) = 37.98 g/mol.
- 1 mole of (F2) [which has 37.98 g/mol] contains Avogadro’s number of molecules (6.02×10^23 molecules),
so 1 mole of (F2) with 37.98 g/mol → 6.02×10^23 molecules.
- Using cross multiplication,
37.98 g/mol of (F2) → 6.02 ×10^23 molecules
? → 5.00 ×10^23 molecules
Hence the mass of 5.00×10^23 molecules of F2 = (37.98 × 5.00 × 10^23) / 6.02 ×10^23 = 31.55 g..
Answer: -134 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_{HNO_3}\times \Delta H_{HNO_3})+(n_{NO}\times \Delta H_{NO})]-[(n_{H_2O}\times \Delta H_{H_2O})+(n_{NO_2}\times \Delta H_{NO_2})]](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5B%28n_%7BHNO_3%7D%5Ctimes%20%5CDelta%20H_%7BHNO_3%7D%29%2B%28n_%7BNO%7D%5Ctimes%20%5CDelta%20H_%7BNO%7D%29%5D-%5B%28n_%7BH_2O%7D%5Ctimes%20%5CDelta%20H_%7BH_2O%7D%29%2B%28n_%7BNO_2%7D%5Ctimes%20%5CDelta%20H_%7BNO_2%7D%29%5D)
where,
n = number of moles
Now put all the given values in this expression, we get
![\Delta H=[(2\times -207)+(1\times 90)]-[(1\times -286)+(3\times 32)]](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5B%282%5Ctimes%20-207%29%2B%281%5Ctimes%2090%29%5D-%5B%281%5Ctimes%20-286%29%2B%283%5Ctimes%2032%29%5D)
Therefore, the enthalpy change for this reaction is, -134 kJ
