69. The student's skin was obviously warmer than the initial temperature of the bracelet. According to the second law of thermodynamics, heat transfers from a higher temperature to a lower temperature hence heat transfers from the student's skin to the bracelet warming up the bracelet.
70. moles of copper=mass of copper/molar mass of copper
=30.1g/(63.55g/mol)= 0.4736 moles Cu
71. Delta H( heat released) = mCp(deltaT) = 30.1g(0.385 J/gK)(33-19)K = 162.23J
72. Copper is chemically less active than iron.
Answer:
violet
Explanation:
Waves with a short wavelength have the most energy. Red waves have a relatively long wavelength (in the 700 nm range), and violet waves are much shorter - roughly half that. Because violet waves have the shortest wavelength of the visible light spectrum, they carry the most energy (google)
Answer:
0.2
Explanation:
1. First, figure out the molar mass of said element(s).
The molar mass of carbon is 12.0107. Whether you round this or leave it as is depends on your's and/or your teacher's personal preference.
2. Next, convert grams to moles by dividing the initial mass of carbon by the molar mass. Round if neccecary.
2.4g ÷ 12.0107g/mol = 0.2mol
True.
For example: Sodium oxide and Nitric acid; both compounds contain oxygen.
Answer:
Because as we move down the group size/ radius of atom increases due to increase in shells and screening effect. The hold of nucleus on valence electrons decreases and effective nuclear charge decreases so it is easy to remove electron from greater sized atoms as compared to smaller sized aroms.
Energy required to remove electron is ionization energy so greater sized atoms have low ionization energy.
Explanation:
