Answer:
b. 54.9%
Explanation:
An emerald gemstone has the formula Be₃Al₂Si₁₆O₁₈. We can find the mass of each element in 1 mole of Be₃Al₂Si₁₆O₁₈ by multiplying the molar mass of the element by its atomicity.
Be: 3 × 9.01 g = 27.03 g
Al: 2 × 26.98 g = 53.96 g
Si: 16 × 28.09 g = 449.4 g
O: 18 × 16.00 g = 288.0 g
Total mass = 818.4 g
The mass percentage of silicon is:
(449.4 g / 818.4 g) × 100% = 54.91%
Don't trust atoms, they make up everything.
How about chemical workers... are they unionized?
Answer:
The FWS use a captive breeding program to start populations in 8 states
Explanation:
I just took a quiz and got this answer right.
First, we convert the masses into fractions
<span>138 g of benzene = 1.77 moles benzene
91.2 g of heptane = 0.93 moles heptane
Next, calculate the mole fractions
x1 (benzene) = 1.77 / (1.77 + 0.93) = 0.66
x2 (heptane) = 1 - 0.66 = 0.34
</span>The vapor pressure of pure benzene is 322 torr at 40 C.
At the same temperature, the vapor pressure of heptane is 92 torr.
<span>
The partial pressure of benzene is
p1 = 0.66 (322) = 212.52 torr
The partial pressure of heptane is
p2 = 0.34 (92) = 31.28 torr
</span>
Light energy is a form of electromagnetic radiation. Light consists of photons, which are produced when an object's atoms heat up. Light travels in waves and is the only form of energy visible to the human eye.
