<span>Ultra violet light is the catalyst that converts 7-dehydrocholesterol to provitamin D3. Ultra violet light can be obtained from the sun. The conversion happens when UVB light hits the skin (where 7-dehydrocholesterol naturally resides), gets absorbed, and us metabolized inside of the body.</span>
Answer:
420.7 degrees C
Explanation:
Use the formula V1/T1 = V2/T2 (Charles' Law) to find T2. Make sure to convert your temperatures to Kelvin by adding 273 to the Celsius temperature.
V1 = 4.50 L
V2 = 10 L
T1 = 39.2 C = 312.2 K
Solve V1/T1 = V2/T2 for T2 and you get T2 = V2T1/V1
T2 = (10 L)(312.2 K) / (4.50 L) = 693.8 K
You can subtract 273 to get the temperature back to Celsius.
T2 = 693.8 - 273 = 420.7 degrees C
Answer:
A. Because they are compounds, they cannot be pure substances.
Explanation:
The false statement from the given choices is that because they are compounds they cannot be pure substances. In fact, because they are compounds they are pure substances.
Pure substances are made up of elements and compounds and they have the following properties:
- All parts are the same throughout
- Composition is definite
- They cannot easily be separated or broken
- Separation by physical method is not easy
- They have unique sets of physical and chemical properties.
Answer:
d = 3.11 g /cm³
Explanation:
Volume -
The volume of a cuboidal object can be calculated by multiplying the length , width and height ,
Hence , Volume ( V ) = l * w * h ,
From the question ,
l = 8.2 cm
w = 3.8 cm
h = 7 cm
Hence, the volume is ,
V = l * w * h
V = 8.2 cm * 3.8 cm * 7 cm
V = 218.12 cm³
Density -
Density of a substance is given as the mass divided by the volume ,
Hence,
d = m / V
From the question,
m = 0.68 kg
since ,
1 kg = 1000g
m = 0.68 * 1000 = 680 g
V = 218.12 cm³ ( calculated above )
Hence , the value of density can be calculated by using the above equation,
d = m / V
d = 680 g / 218.12 cm³
d = 3.11 g /cm³
Answer:
10 kg of water was added to the 20 kg of seawater to dilute it from 3% to 2%. Hope this helps!!!!!!
