Answer: +4
Explanation:
Firstly, we know that Oxygen should have an oxidation number of -2. This is because according to oxidation rules, Oxygen's number will always be -2 unless it is a part of a peroxide and then it will be -1 (ex: H2O2). UO2 is not a peroxide, so the regular rules will apply.
We also know that oxidation numbers in a molecule with no charge should add up to zero. There are two oxygen molecules which makes their total oxidation numbers equal to -4. Therefore, whatever U's oxidation number is should cancel out that -4 to make the total number 0.
So, U's oxidation number should be +4 since -4+4=0.
b. gram
c. angstrom
d. nanogram
b. dizzy spells
c. stroke
d. heart attack
What volume of oxygen at STP is required for the complete combustion of 100.50 mL of C2H2?
201 mL
201.00 mL
251 mL
251.25 mL
251.25 mL of O₂
The balance chemical equation is as follow,
2 C₂H₂ + 5 O₂ → 4 CO₂ + 2 H₂O
As we know if the gas is acting ideally then 1 mole of any gas at standard temperature and pressure it will occupy exactly 22.4 L or 22400 mL of volume.
Keeping this in mind according to equation,
44800 mL (2 mol) of C₂H₂ required = 112000 mL (5 mol) of O₂
So,
100.50 mL of C₂H₂ will require = X mL of O₂
Solving for X,
X = (100.5 mL × 112000 mL) ÷ 44800 mL
X = 251.25 mL of O₂
The balanced reaction would be:
C2H2 + 5/2O2 = 2CO2 + H2O
We are given the amount of acetylene in the reaction. This will be the starting point of our calculation. We use the ideal gas equation to find for the number of moles.
n = PV / RT = 1.00(.1005 L) / (0.08206 atm L/mol K ) 273.15 K
n= 4.4837 x 10^-3 mol C2H2
4.4837 x 10^-3 mol C2H2 (5/2 mol O2/ 1 mol C2H2) = 0.0112 mol O2
V = nRT/P = 0.0112 mol O2 x 273.15 K x 0.08206 atm L/mol K / 1 atm
V=0.25125 L or 251.25 mL
Explanation:
Let's analyze the statements one by one:
a) This process is exothermic.
True. The negative enthalpy change (-2,021 kJ) indicates that heat is released during the reaction, making it exothermic.
b) The enthalpy change for 2C₃H₇OH(l)+9O₂(g)→6CO₂(g)+8H₂O(l) is 2,021 kJ.
False. The balanced chemical equation and enthalpy change given are for the combustion of 1 mole of propanol, not 2 moles.
c) The enthalpy change for 2C₃H₇OH(l)+9O₂(g)→6CO₂(g)+8H₂O(l) is -4,042 kJ.
False. This statement suggests a doubled enthalpy change value in the wrong direction. The correct direction is negative (exothermic), but the magnitude is not doubled.
d) The enthalpy change for 2C₃H₇OH(l)+9O₂(g)→6CO₂(g)+8H₂O(l) is -2,021 kJ.
False. This statement suggests the correct direction but doubles the magnitude. The correct magnitude is -2,021 kJ for 1 mole of propanol.
e) This chemical process transfers heat from the surroundings to the system.
False. The process is exothermic, which means it releases heat from the system to the surroundings.
f) The enthalpy change for 2C₃H₇OH(l)+9O₂(g)→6CO₂(g)+8H₂O(l) is 4,042 kJ.
False. This statement suggests the correct magnitude but in the wrong direction. The correct direction is negative (exothermic).
g) This process is endothermic.
False. The process is exothermic, as indicated by the negative enthalpy change.
h) This chemical process transfers heat from the system to the surroundings.
True. An exothermic process like this releases heat from the system to the surroundings.
So, the correct statements are:
a) This process is exothermic.
e) This chemical process transfers heat from the surroundings to the system.
h) This chemical process transfers heat from the system to the surroundings.
Answer:
If you change the number of protons an atom has, it becomes a different element. If you change the number of nutrons it has, it becomes a different isotope.
Explanation:
denitrifying bacteria
bacteria that break apart cellulose
nitrogen-fixing bacteria
Answer: nitrogen fixing bacteria
Explanation:
Most plants and animals are dependent on nitrogen fixing bacteria for their nitrogen requirements. As they are incapable of absorbing the atmospheric nitrogen directly. The soil bacteria traps the atmospheric nitrogen convert it into forms like ammonia, nitrates and nitrites which are readily absorbed by the plants and some soil borne animals.