Answer: The rate constant is
Explanation ;
Expression for rate law for first order kinetics is given by:

where,
k = rate constant = ?
t = age of sample = 4.26 min
a = initial amount of the reactant = 2.56 mg
a - x = amount left after decay process = 2.50 mg
Now put all the given values in above equation to calculate the rate constant ,we get



Thus rate constant is [tex]0.334s^{-1}
Answer:
Amount of excess Carbon (ii) oxide left over = 23.75 g
Explanation:
Equation of the reaction: Fe₂O₃ + 3CO ----> 2Fe + 3CO₂
Molar mass of Fe₂O₃ = 160 g/mol;
Molar mass of Carbon (ii) oxide = 28 g/mol
From the equation of reaction, 1 mole of Fe₂O₃ reacts with 3 moles of carbon (ii) oxide; i.e. 160 g of iron (iii) oxide reacts with 84 g (3 * 28 g) of carbon (ii) oxide
450 g of Fe₂O₃ will react with 450 * 84/180) g of carbon (ii) oxide = 236..25 g of carbon (ii) oxide
Therefore the excess reactant is carbon (ii) oxide.
Amount of excess Carbon (ii) oxide left over = 260 - 236.25
Amount of excess Carbon (ii) oxide left over = 23.75 g
Answer:
<h2>
total no. of electron present in Valency shell is called valency electron </h2><h2>___________________</h2>
<h2>valency shell is that in which last electron is present</h2>
B)
oxygen is oxidized.
<h3>Further explanation</h3>
Given
photosynthesis reaction
6CO2 + 6H20 ⇒ C6H12O6 +
602
Required
the oxidation compound
Solution
Oxidation-reduction reactions or abbreviated as Redox are chemical reactions in which there is a change in oxidation number
Oxidation is an increase in oxidation number, whereas Reduction is a decrease in oxidation number.
In the photosynthetic reaction, oxidation and reduction reactions occur in:
CO2 to C6H12O6 : reduction
Oxidation number of C from +4 to 0
H2O to O2 : oxidation
Oxidation number of O from -2 to 0