4. A sample of silicon contains<br> 5.23 x 1011 atoms. Write this amount<br> as a whole number.

What percentage of solar radiation striking a plant is converted into chemical energy?

VMariaS [2998]

1 percent of the solar radiation

3 0

2 months ago

Chlorine atoms from CFC molecules speed the breakdown of stratospheric O3 in a process that is affected by both homogeneous and

eduard [2782]

False, it's solely heterogeneous. Explanation: The degradation of the ozone layer caused by CFC molecules happens in the gaseous state since it does not involve liquids or solids at stratospheric conditions. Additionally, the reaction occurs independently as ozone is chemically unstable, eliminating the need for a catalyst.

7 0

2 months ago

The concentration of Si in an Fe-Si alloy is 0.25 wt%. What is the concentration in kilograms of Si per cubic meter of alloy?

KiRa [2933]

Answer: The mass of Si in kilograms is, $19.55kg/m^3$

Explanation:

Given that the Si concentration in an Fe-Si alloy is 0.25 weight percent, this translates to:

Mass of Si = 0.25 g = 0.00025 kg

Mass of Fe = 100 - 0.25 = 99.75 g = 0.09975 kg

Density of Si = $2.32g/cm^3=2.32\times 10^6g/m^3$

Density of Fe = $7.87g/cm^3=7.87\times 10^6g/m^3$

Next, we need to find the quantity of Si in kilograms per cubic meter of alloy.

Si concentration in kilograms = $\frac{\text{Weight of Si in 100 g of alloy}}{\text{Volume of 100 g of alloy}}$

Si concentration in kilograms = $\frac{\text{Weight of Si in 100 g of alloy}}{\frac{\text{Wight of Fe}}{\text{Density of Fe}}+\frac{\text{Wight of Si}}{\text{Density of Si}}}$