Molar mass of Calcium ( Ca ) = 40.078 g/mol
Number of moles in 9.8 grams :
1 mole Ca -----------> 40.078 g
mole Ca -------------> 9.8 g
moles Ca = 9.8 / 40.078
moles Ca = 0.2445 moles
number of molecules:
1 mole ----------------> 6.02x10²³ molecules
0.2445 moles --------> ?
= 0.2445 * 6.02x10²³
= 1.47x10²³ molecules
hope this helps!.
homo sapiens leave africa at approximately 200,000 years ago.
The density of this object would be 2. It would be two because to find density you have to do mass divided by volume. So 40g divided by 20 cubed cm = 2g/cm cubed
Answer:
See explanation below
Explanation:
3. Each atom has unique electron energy level when compared to other, when electron relaxes from an excited energy level, it emits energy in the form of electromagnetic waves with energy equals to the difference between energy of ground and excited state. As electromagnetic wave wavelength obeys planck relation

And the energy of each photon in electromangetic wave of specific frequency is

Where h is planck's constant
We can see that the wavelength, which determines color and position of bright line in spectroscope corresponds directly to the energy of electromagnetic wave, and thus, the characteristic energy of atom.
4. From the answer above, you now know that electronic transition can emit electron with specific wavelength. In strontium, emission of colored light occurs by the relaxation of electrons in excited state such that the difference between excited energy level and ground level falls in the energy of visible light spectral range.
5. In Na, ground state configuration is 2-8-1. 2-7-1-1 indicates that one of electron in ground state got excited by external energy to excited state, and thus, indicates that Na atom is in excited state
Each alcohol's alkene product when dehydrated are:
a) cyclohexanol when dehydrated = cyclohexene
b) 1-methylcyclohexanol when dehydrated =<span> methylcyclohexene </span>
c) 2-methylcyclohexanol when dehydrated =<span> methylcyclohexene </span>
d) 2,2-dimethylcyclohexanol when dehydrated =<span> 1,2-methylcyclohexene </span>
e) 1,2-cyclohexanediol when dehydrated = cyclohexanone