They reduce viral transmission (if worn correctly). ...
They prevent asymptomatic spread. ...
You're protecting others from illness. ...
They're mandated by law in some states. ...
They're good hygiene in general.
Answer:
d. N
Explanation:
Chemical equation:
Pb(NO₃)₂(aq) + K₂SO₄(aq) → PbSO₄(s) + KNO₃(aq)
Balanced Chemical equation:
Pb(NO₃)₂(aq) + K₂SO₄(aq) → PbSO₄(s) + 2KNO₃(aq)
Ionic equation:
Pb²⁺(aq) + 2NO₃⁻(aq) + 2K⁺(aq) + SO₄²⁻(aq) → PbSO₄(s) + 2K⁺(aq) + 2NO₃⁻(aq)
Net ionic equation:
Pb²⁺(aq) + SO₄²⁻(aq) → PbSO₄(s)
The NO₃⁻(aq) and K⁺(aq)are spectator ions that's why these are not written in net ionic equation. The PbSO₄ can not be splitted into ions because it is present in solid form.
Spectator ions:
These ions are same in both side of chemical reaction. These ions are cancel out. Their presence can not effect the equilibrium of reaction that's why these ions are omitted in net ionic equation.
3.9 grams CaCO3
The mass of 2.0 L of water with a density of 1.00 g/ml is 2000 grams.And 1 ppm of that is 2000 / 1000000 = 0.002 grams. So just multiply by the ppm of CaCO3, giving 0.002 g * 1.95x10^3 = 3.90 grams.
Since the least accurate datum we have is 2 significant figures, the result should be rounded to 2 significant figures, giving 3.9 grams.
Answer:
E. better schools
Explanation:
This contributes the most to human development in his community because it provides children with more resources and better opportunities than a sub-par education system. If a community is able to better their school system, they will begin to see a lot of positive changes in their area.