Surface tension under water results from greater attraction of liquid molecules to each other, due to a process called cohesion, than to molecules in the air, due to a process called adhesion.
Answer:
4121 years
Explanation:
From;
0.693/t1/2 = 2.303/t log No/N
t1/2= half life of the carbon-14
No= count rate of the living tissue
N= count rate of the sample
t = age of the sample
0.693/5730 =2.303/t log (13.5/8.2)
1.21 * 10^-4 = 2.303/t * 0.2165
1.21 * 10^-4 = 0.4986/t
t = 0.4986/1.21 * 10^-4
t = 4121 years
Nitrogen — 78 percent.
Oxygen — 21 percent.
Argon — 0.93 percent.
Carbon dioxide — 0.04 percent.
Trace amounts of neon, helium, methane, krypton and hydrogen, as well as water vapor.
The balanced equation :
<em>2Al₂O₃⇒ 4Al+3O₂</em>
<h3>Further explanation</h3>
Given
Reaction
Al₂O₃⇒ Al+O₂
Required
Balanced equation
Solution
A chemical reaction is said to be balanced if the number of elements involved in the reaction is the same (either the reactants or the products)
The reaction above is said to be unbalanced because the number of elements Al and O in the reactants and products is not the same.
The balancing step
1. Give a coefficient
Al₂O₃⇒ aAl+bO₂
2. Make an equation
Al, left = 2, right = a⇒a=2
O, left = 3, right = 2b⇒2b=3⇒b=3/2
The equation becomes :
Al₂O₃⇒ 2Al+3/2O₂ x2
<em>2Al₂O₃⇒ 4Al+3O₂</em>
Answer:
the molecular formula of the compound is N2O4
Explanation:
- Find the empirical formula
mole of N present = mass of N divided by molar mass of N = 0.140/14 = 0.01 mole
mole of O present = mass of O divided by molar mass of O = 0.320/16 = 0.02 mole
Divide both by the smallest number of mole to determine the coefficient of each, the smallest number of mole is 0.01 thus:
quantity of N = 0.01/0.01 = 1
quantity of O = 0.02/0.01= 2
thus the empirical formula = NO2
- Now determine the molecular formula by finding the ratio of molecular formula and empirical formula
Molar mass of molecular formula = 92.02 amu = 92.02 g/mole
Molar mass of empirical formula NO2 = (14 + (16 x 2)) = 46 g/mole
the x factor = 92.02/46 = 2
Molecular formula = 2 x NO2 = N2O4
