Okay
Mr (H2O)= 18g
therefore moles of H2O
is 720.8/18= 40.04mol
the ratio of H2 to O2 to H2O is
2 : 1 : 2
so moles of H2 is same as H2O here
H2= 40.04moles
moles of O2 is half
so 40.04 x 0.5
20.02moles
grams of O2 is
its moles into Mr of O2
that's 20.02 x 32 = 640.64g
2 Al + 6 HCl → 2 AlCl₃ + 3 H₂ (single displacement)
Ca + Br₂ → CaBr₂ (synthesis)
4 NH₃ + 5 O₂ → 4 NO + 6 H₂O (combustion)
2 NaCl → 2 Na + Cl₂ (decomposition)
FeS + 2 HCl → FeCl₂ + H₂S (double displacement)
single displacement - is a chemical reaction of the following type: A + BC → AC + B
double displacement - is a chemical reaction of the following type: AB + CD → AC + BD
synthesis - the chemical product is obtained by combining in a synthesis the constituent elements
combustion - usually a exothermic reaction of a particular compound with oxygen
decomposition - degradation of a compound in simpler elements
Answer:
True
Explanation:
Significant digits are numbers that helps to present the precision of measurements calculations.
Numbers that do not contribute to the precision of a reading should not be counted as significant.
There are rules of assigning significant numbers:
- Leading or trailing zeros are insignificant and should only be counted as a place holder.
- All non-zero digits are significant
- Zeroes between non-zero digits are significant.
- Leading zeros in a decimal are significant before the number.
- All the numbers in a scientific notation are significant.
Do not ionize in solutions
Poor conductors of electricity/heat
Low melting/boiling points
gases or liquids at room temperature
The penetrating power of alpha rays, beta rays, and gamma rays varies greatly. Alpha particles can be blocked by a few pieces of paper. Beta particles pass through paper but are stopped by aluminum foil. Gamma rays are the most difficult to stop and require concrete, lead, or other heavy shielding to block them.
