Answer:
2 g/mL
Explanation:
The following data were obtained from the question:
Mass (m) = 5 g
Volume (V) = 2.5 mL
Density (D) =.?
Density is simply defined as the mass of substance per unit volume of the substance. Mathematically, it is expressed as:
Density (D) = mass (m) /volume (V)
D = m/V
With the above formula, we can obtain the density of the ball as follow:
Mass (m) = 5 g
Volume (V) = 2.5 mL
Density (D) =.?
D = m/V
D = 5/2.5
D = 2 g/mL
Therefore, the density of the ball is 2 g/mL.
What is the theoretical yield of aluminum oxide if 2.40 mol of aluminum metal is exposed to 2.10 mol of oxygen?<span><span>Ask for details </span><span>Follow </span>Report</span><span> by <span>Sapperd2248 </span><span>1 minute ago
1879</span></span>
Answer:
It takes 178.4 years to drop the activity from 15.0 Ci to 0.25 Ci
Explanation:
Step 1: Data given
Half-life time = 30.2 years
Initial activity = 15.0 Ci
Final activity = 0.250 Ci
Step 2: Calculate the time needed
N / No = e^(-0.693 * t / T1/2)
⇒ with N = The activity after dropped = 0.250 Ci
⇒ with N0 = the initial activity = 15.0
⇒ with t= the time (in years) needed to drop the activity from 15.0 to 0.250
⇒ with t1/2 = the half- life time is 30.2 years
0.250 / 15.0 = e^(-0.693 * t / 30.2)
ln(0.250/15.0) = (-0.693 * t / 30.2)
-4.09 * 30.2 = -0.693t
-123.65 = -0.693t
t= 178.4 years
It takes 178.4 years to drop the activity from 15.0 Ci to 0.25 Ci