America's age = 243.85 years
<h3>Further explanation</h3>
When converting units, list and multiply all the units until you find the unit you want
Time unit conversion
1 year = 365 days
1 day = 24 hours
1 hour = 3600 s
7.69 x 10⁹ seconds to years :

Answer:
A. To focus on only those ions that form the precipitate
Explanation:
Net ionic equations cancel out the ions that appear on both sides of the reaction because they essentially don't participate in the reaction. This is very useful when dealing with redox reactions because are complicated enough without spectator ions being in the way, so they help focus on those ions that actually form the precipitate.
Key Terms
- Spectator Ions: an ion that does not take part in the chemical reaction.
- Net ionic equations: a equation where ions that appear on both sides are canceled out.
- Redox reaction: an oxidation-reduction reaction.
The mass numbers for two isotopes are unequal because they have different numbers of NEUTRONS.
Answer:
B
Explanation:
first find the no. Of moles of H2SO4
= 75/98.1
= 0.7645
Next step
In on mole of H2SO4 the no.of oxygen atom is 4.
1 H2SO4 : 4 O
0.7645 : x x= 0.7645x4= 3.0581
next multiply avogadros constant
3.0581 x 6.022× 10^23 =1.84x10^24
NH3. Ammonia is composed of one nitrogen atom, and three hydrogens.