The green and black symbols refer to atoms, that make up the molecule of water, more specifically you can say that the 2 Hydrogen atoms are the black ones found outside, while the central atom, that is also green would be oxygen.
Answer:
The pressure in mmHg is 1253 (option C)
Explanation:
Two quantities are directly proportional if when multiplying or dividing one of them by a number, the other is multiplied or divided by that number. In other words, the magnitudes are directly proportional when one magnitude increases and so does the other in the same proportion; or when one magnitude decreases and so does the other in the same proportion.
The rule of three or is a way of solving proportionality problems between three known values and an unknown value, which can be applied to directly proportional quantities as follows:
a ⇒ b
c ⇒ x
So 
where a, b and c are data and x is the unknown value to be calculated.
In this case, knowing that 1 Torr = 1 mmHg, the rule of three can be applied as follows: if 1 torr is equal to 1 mmHg, 1253 torr is equal to how many mmHg?

pressure= 1253 mmHg
<u><em>The pressure in mmHg is 1253 (option C)</em></u>
Answer:
mass 1.25 Liters NH₃(gas) = 0.949 grams (3 sig-figs)
Explanation:
At STP (Standard Temperature-Pressure conditions => 0°C(=273K) and 1atm pressure, 1 mole <u>any</u> gas will occupy 22.4 Liters.
So, given 1.25 Liters ammonia gas at STP, convert to moles then multiply by formula wt. (17g/mole gives mass of NH₃.
moles NH₃(gas) = 1.25L NH₃(gas)/22.4L NH₄(gas)· NH₃(gas)mole⁻¹ = 0.0558 mole NH₃(gas).
Converting to grams NH₃(gas) = 0.0558 mole NH₃(gas) x 17 g·mol⁻¹ = 0.949 grams NH₃(gas).
Answer:
losing electrons and gaining positive charges. atoms that lose electrons were oxidized
Explanation: