Answer:
10.2 mg
Explanation:
Step 1: Calculate the total amount of water she drank
1 year has 365 days and she lived in Chicago for 2 years = 2 × 365 days = 730 days.
If she drank 1.4 L of water per day, the total amount of water she drank is:
730 day × 1.4 L/day = 1022 L
Step 2: Calculate the amount of Pb in 1022 L of water
The concentration of Pb is 10 ppb (10 μg/L).
1022 L × 10 μg/L = 10220 μg
Step 3: Convert 10220 μg to milligrams
We will use the conversion factor 1 mg = 1000 μg.
10220 μg × 1 mg/1000 μg = 10.2 mg
Answer:
24.6g of NaCl
Explanation:
Expression of the reaction:
2NaCl → 2Na + Cl₂
Given parameters:
Mass of Cl₂ = 15g
Unknown:
Mass of NaCl = ?
Solution:
To solve this problem, we have to use mole relationships.
Find the number of moles of the mass of the given specie;
Number of moles = 
Molar mass of Cl₂ = 2(35.5) = 71g/mol
Number of moles = 
= 0.21mole
Now;
From the balanced reaction equation;
1 mole of Cl₂ is produced from 2 moles of NaCl;
0.21 mole of Cl₂ will be produced from 0.21 x 2 = 0.42mole of NaCl
So,
Mass of NaCl = number of moles x molar mass
Molar mass of NaCl = 23 + 35.5 = 58.5g/mol
Mass of NaCl = 0.42 x 58.5 = 24.6g of NaCl
Answer:
-10 m/s2
Explanation:
The acceleration is taken as −10 m/s2
The correct answer is:
a positron is emitted when proton converts to a neutron.
The reaction can be described as following:
₁¹p (proton) → ₀¹n (neutron) + ₁°e (positron or ₁⁰β)
Positron is an antiparticle of a β particle (₋₁°β), which means it has an oposite charge to it, but same mass.
