I suck at chemistry but i have a friend that can help
Answer:
4 g OF IODINE-131 WILL REMAIN AFTER 32 DAYS.
Explanation:
Half life (t1/2) = 8 days
Original mass (No) = 64 g
Elapsed time (t) = 32 days
Mass remaining (Nt) = ?
Using the half life equation we can obtain the mass remaining (Nt)
Nt = No (1/2) ^t/t1/2
Substituting the values, we have;
Nt = 64 * ( 1/2 ) ^32/8
Nt = 64 * (1/2) ^4
Nt = 64 * 0.0625
Nt = 4 g
So therefore, 4 g of the iodine-131 sample will remain after 32 days with its half life of 8 days.
Answer:
40 g NaOH
Step-by-step explanation:x
To make 500 mL of a 2 mol·L⁻¹ solution, the technician must measure the correct mass of NaOH.
Step 1. Calculate the <em>moles of NaOH
</em>
c = n/V Multiply both sides by V
n = Vc
c = 2 mol·L⁻¹
V =0.5 L
n = 0.5 × 2
n = 1 mol NaOH
Step 2. Calculate the <em>mass of NaOH
</em>
The molar mass of NaOH is 40.00 g/mol.
m = 1 × 40.00/1
m = <em>40 g NaOH
</em>
The technician must measure <em>40 g of NaOH</em>.