Radioactive material undergoes 1st order decay kinetics.
For 1st order decay, half life = 0.693/k
where k = rate constant
k = 0.693/half life = 0.693/8.02 = 0.0864 day-1
Now, for 1st order reaction,
k =
Given: t = 6.01d, initial conc. = 5mg
∴0.0864 =
∴ final conc. = 2.975 mg
<u>Answer:</u>
Pyrite leaves behind a green-black streak when it is rubbed against an unglazed porcelain plate as a part of the streak test process.
<u>Explanation:</u>
Different minerals produce different coloured streaks when rubbed against a white ceramic or porcelain streak plate. This streak test is done to identify the mineral and distinguish the same from other minerals that look similar in colour and texture.
It must be ensured that the test is done on clean and fresh specimens of the mineral and that there must be no contaminants. Pyrite specimens are usually brass-yellow colour but it leaves a green-black streak when the streak test is done.
Explanation :
The balanced chemical reaction will be,
By the stiochiometry, 3 moles of solid copper(II)oxide react with 2 moles of ammonia gas to give 3 moles of copper metal, 1 mole of nitrogen gas and 3 moles of liquid water.
The states of matter of each elements and compound is,
Copper(II)oxide is in solid state
Ammonia is in gaseous state
Copper metal is in solid state
Nitrogen is in gaseous state
Water is in liquid state
Answer:
B.
Explanation:
Gravity acts on all masses equally, even though the effects on both masses.
Hope it helps you! ^^

Given data:
Mass of copper (m) = 20.0 g
Initial temperature of Copper (T1)= 25 C
Final temperature = T2
Heat absorbed by copper (Q) = 475 J
Specific heat of Copper (c) = 0.385 J/g C
Formula:
Q = mcΔT
= mc(T2-T1)
475 = 20*0.385*(T2-25)
62.08 = T2-25
T2 = 87.08 = 87.1 C
