Closed system. If the system is not closed, matter or energy can escape from the system. an example of this is if you react magnesium and hydrochloric acid in a open system. The H₂ gas is going to escape making it look like some of the mass disappeared . in that same reaction some in an open system will also loose heat to the surrounding which will make it look like less heat was produced.
Answer:
12.50g
Explanation:
T½ = 2.5years
No = 100g
N = ?
Time (T) = 7.5 years
To solve this question, we'll have to find the disintegration constant λ first
T½ = In2 / λ
T½ = 0.693 / λ
λ = 0.693 / 2.5
λ = 0.2772
In(N/No) = -λt
N = No* e^-λt
N = 100 * e^-(0.2772*7.5)
N = 100*e^-2.079
N = 100 * 0.125
N = 12.50g
The sample remaining after 7.5 years is 12.50g
Answer:
v = 23.96 cm³
Explanation:
Given data:
Mass = 15.0 g
Density = 0.626 g/cm³
Volume = ?
Solution:
Formula:
D=m/v
D= density
m=mass
V=volume
Now we will put the values in formula:
d = m/v
v = m/d
v = 15 g / 0.626 g/cm³
v = 23.96 cm³
Initial concentration of magnesium nitrate M1 = 2.13 M
Initial volume of magnesium nitrate, MgNO3 V1 = 1.24 L
Final concentration of MgNO3, M2 = 1.60 M
Let the final volume of MgNO3 upon dilution be V2
Formula to use:
M1*V1 = M2*V2
V2 = M1*V1/M2
= 2.13 M * 1.24 L/1.60 M = 1.65 L
Thus, the final volume of magnesium nitrate solution upon dilution is 1.65 L
H :) (I tried sorry if im wrong)
