To determine the mass of gold, we simply multiply the density and volume. Density is a value for mass, such as kg, divided by a value for volume, such as m3. Density is a physical property of a substance that represents the mass of that substance per unit volume. We do as follows:
mass = density x volume
mass = 19.3 g/cm^3 ( 16.0 cm^3 )
mass = 308.8 g
Argon is a suitable choice for light bulbs because it is inert. Compared to a reactive gas like oxygen, the metal filimant would burn up in a reactive environment, which is why a noble gas is used.
Step 
<u>find the mass of a single washer</u>
Divide the total mass by the number of washers
Step 
<u>Convert kg to mg</u>
we know that
so
therefore
<u>the answer is</u>
Answer: After three half-lives 1/8 (12.5%) of the original sample remains
Answer:
Photon of light
Explanation:
According to Bohr's model of the atom, electrons in atoms are found in specific energy levels. These energy levels are called stationary states, an electrons does not radiate energy when it occupies any of these stationary states.
However, an electron may absorb energy and move from one energy level or stationary state to another. The energy difference between the two energy levels must correspond to the energy of the photon of light absorbed in order to make the transition possible.
Since electrons are generally unstable in excited states, the electron quickly jumps back to ground states and emits the excess energy absorbed. The frequency or wavelength of the emitted photon can now be measured and used to characterize the transition. This is the principle behind many spectrometric and spectrophotometric methods.
