Answer:
The period 4 alkaline-earth metal has the name Calcium. An isotope of this element having 20 neutrons has a mass number of 40.
Explanation:
Looking at the periodic table 4th row for the alkaline-earth metal, we can find Calcium which has an atomic number of 20 (or protons number, or z). The mass number is given by the sum of protons and neutrons. If the number of protons in this case is 20 and the number of neutrons is also 20, the mass number A = 40.
Answer:
The final mass of sample is 1.3 g.
Explanation:
Given data:
Half life of H-3 = 12.32 years
Amount left for 15.0 years = 3.02 g
Final amount = ?
Solution:
First all we will calculate the decay constant.
t₁/₂ = ln² /k
t₁/₂ =12.32 years
12.32 y = ln² /k
k = ln²/12.32 y
k = 0.05626 y⁻¹
Now we will find the original amount:
ln (A°/A) = Kt
ln (3.02 g/ A) = 0.05626 y⁻¹ × 15.0 y
ln (3.02 g/ A) = 0.8439
3.02 g/ A = e⁰°⁸⁴³⁹
3.02 g/ A = 2.33
A = 3.02 g/ 2.33
A = 1.3 g
The final mass of sample is 1.3 g.
Water Is A Liquid And Gravity Pulls Objects Up
The acronym is RNA. Ribo Nucleic Acid
Answer:
4244.48 g to the nearest hundredth.
Explanation:
The molar mass of Glucose = 6*12.011 + 12*1.008+ 6*15.999
= 180.156.
So 23.56 moles = 180.156 * 23.56 = 4244.48 g