From the calculations, the half life of the material is 6.5 days.
<h3>What is radioactivity?</h3>
The term radioactivity has to do with the spontaneous disintegration of a specie.
Uisng the formula;
N=Noe^-kt
N= amount at time t = 0.135 Ci or 4.995 ×10^9 Bq
No = amount initially present = 1.75 x 10^12 Bq
k = rate constant = ?
t = time taken = 55 days
Hence;
4.995 ×10^9 = 1.75 x 10^12e^-55k
4.995 ×10^9/1.75 x 10^12 = e^-55k
2.85 * 10^-3 = e^-55k
ln2.85 * 10^-3 = -55k
k = ln2.85 * 10^-3/-55
k = 0.1066 day-1
Half life = 0.693/ 0.1066 day-1
= 6.5 days
Learn more about radioactivity:brainly.com/question/1770619
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a. 34 mL; b. 110 mL
a. A tablet containing 150 Mg(OH)₂
Mg(OH)₂ + 2HCl ⟶ MgCl₂ + 2H₂O
<em>Moles of Mg(OH)₂</em> = 150 mg Mg(OH)₂ × [1 mmol Mg(OH)₂/58.32 mg Mg(OH)₂
= 2.572 mmol Mg(OH)₂
<em>Moles of HCl</em> = 2.572 mmol Mg(OH)₂ × [2 mmol HCl/1 mmol Mg(OH)₂]
= 5.144 mmol HCl
Volume of HCl = 5.144 mmol HCl × (1 mmol HCl/0.15 mmol HCl) = 34 mL HCl
b. A tablet containing 850 mg CaCO₃
CaCO₃ + 2HCl ⟶ CaCl₂ + CO₂ + H₂O
<em>Moles of CaCO₃</em> = 850 mg CaCO₃ × [1 mmol CaCO₃/100.09 mg CaCO₃
= 8.492 mmol CaCO₃
<em>Moles of HCl</em> = 8.492 mmol CaCO₃ × [2 mmol HCl/1 mmol CaCO₃]
= 16.98 mmol HCl
Volume of HCl = 16.98 mmol HCl × (1 mL HCl/0.15 mmol HCl) = 110 mL HCl
Answer:
Final temperature = 
Explanation:
Given that,
Heat added, Q = 250 J
Mass, m = 30 g
Initial temperature, T₁ = 22°C
The Specific heat of Cu= 0.387 J/g °C
We know that, heat added due to the change in temperature is given by :
Put all the values,
So, the final temperature is equal to .
Please refer to the attachment for a complete classification of your specified matter.
1. NA = Sodium, NA was the chemicals symbols for the element would be NA because in Latin it is natrium for natron in which is sodium in English, Sodium was created by Humphry Davy in the year of 1807. Element name Sodium, Chemical symbol NA atomic number, 11 Atomic mass 23.
2. AG = Sliver, AG was the chemicals symbols for the element would be AG because in Latin it is argentum in which in English means bright and also sliver. Element name Sliver Chemical symbol AG atomic number, 47 Atomic mass 108.
