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:
D. 76%
Explanation:
Percent yield=actual/theoretical * 100
38/50 * 100 = 76%
Answer:
b.what type of object broke the glass
Explanation:
The point of intersection of all the fracture patterns of the window speaks to the shape, type and dimension of the object that broke the glass.
Procaine hydrochloride ( = 272.77 g/mol) is used as a local anesthetic. Calculate the molarity of a 4.666 m solution which has a density of 1.1066 g/ml.
molarity = Moles of solute / volume of solution
Molarity = m d / [ 1 + (mW / 1000)]
Molarity = 4.666 X 1.1066 / [ 1 + (4.666 X 272.77 / 1000)]
Molarity = 5.16 / 2.272= 2.271 M
Answer:
The "kinetic particle theory" explains the properties of solids, liquids and gases. There are energy changes when changes in state occur.
When heat is added to a substance, the molecules and atoms vibrate faster.
As atoms vibrate faster, the space between atoms increases.
The motion and spacing of the particles determines the state of matter of the substance. The end result of increased molecular motion is that the object expands and takes up more space.