Below are the choices:
Check all that apply
<span>( ) A(g) + B(g) ---> C(g) </span>
<span>( ) 2A(g) +2B(g) ---> 5C(g) </span>
<span>( ) A(s) + B(s) ---> C(g) </span>
<span>( ) 2A(g) + B(g) ---> C(g)
</span>
When a gas is evolved during a chemical reaction, the gas can be imagined as displacing the atmosphere - pushing it back against the atmospheric pressure. The work done is therefore V*P where V is the volume of gas evolved, and P is the atmospheric pressure.
<span>A(g) + B(g) ---> C(g) In this reaction 2 volumes of reagent combine to form 1 vol of product. The total volume falls, so the work done is negative (the atmosphere does work on the gaseous system). </span>
<span>2A(g) +2B(g) ---> 5C(g) 4 vols of reagent combine to form 5 vols of product. The total volume increases and positive work is done. </span>
<span>A(s) + B(s) ---> C(g) we can assume that the volume of gas produced exceeds the volume of solid consumed, so again positive work is done. </span>
<span>2A(g) + B(g) ---> C(g) In this reaction 3 volumes of reagent combine to form 1 vol of product. The total volume falls, so the work done on the atmosphere is negative</span>
Answer:
ten atoms of hydrogen are present in one mole of caffeine.
Explanation:
Molecular formula of caffiene is given which is C3H10N4O2. It clearly shows that ten atoms of hydrogen are present. One mole is amount equal to one molecular weight of a molecule which is derived from molecular formula. So as moecular formula has ten atoms of hydrogen, one mole of caffeine has 10 atoms of hydrogen.
The answer is a Surface wave
- From the general law of gases: PV = nRT,
where P is the pressure (atm),
V is the volume (L),
n is the number of moles,
R is the general gas constant (8.314 L.atm/mol.K),
T is the temperature in Kelvin
- at constant volume of the gas: P1T2 = P2T1
P1 = 3.20 atm, T1 = 300 K, T2 = 290 K, P2 = ??
(3.20 atm)(290 K) = P2(300 K)
P2 = (3.20 atm)(290 K)/ (300 K) = 3.093 atm
Answer: only the VSEPR mode shows the geometric shape of a formula.