The low melting point of the wire is utilized in making electric fuse.
Answer:
5.0 x 10⁹ years.
Explanation:
- It is known that the decay of a radioactive isotope isotope obeys first order kinetics.
- Half-life time is the time needed for the reactants to be in its half concentration.
- If reactant has initial concentration [A₀], after half-life time its concentration will be ([A₀]/2).
- Also, it is clear that in first order decay the half-life time is independent of the initial concentration.
- The half-life of K-40 = 1.251 × 10⁹ years.
- For, first order reactions:
<em>k = ln(2)/(t1/2) = 0.693/(t1/2).</em>
Where, k is the rate constant of the reaction.
t1/2 is the half-life of the reaction.
∴ k =0.693/(t1/2) = 0.693/(1.251 × 10⁹ years) = 5.54 x 10⁻¹⁰ year⁻¹.
- Also, we have the integral law of first order reaction:
<em>kt = ln([A₀]/[A]),</em>
where, k is the rate constant of the reaction (k = 5.54 x 10⁻¹⁰ year⁻¹).
t is the time of the reaction (t = ??? year).
[A₀] is the initial concentration of (K-40) ([A₀] = 100%).
[A] is the remaining concentration of (K-40) ([A] = 6.25%).
∴ (5.54 x 10⁻¹⁰ year⁻¹)(t) = ln((100%)/( 6.25%))
∴ (5.54 x 10⁻¹⁰ year⁻¹)(t) = 2.77.
∴ t = 2.77/(5.54 x 10⁻¹⁰ year⁻¹) = 5.0 x 10⁹ years.
The combstion of ZnS in excess oxygen gives ZnO and SO₂ as the products.
hence the equation should be;
ZnS(s) + O₂(g) →ZnO(s) + SO₂(g)
At the left hand side: At the right hand side:
number of Zn atoms = 1 number of Zn atoms = 1
number of S atoms = 1 number of S atoms = 1
number of O atoms = 2 number of O atoms = 3
Hence the balanced equation is;
2ZnS(s) + 3O₂(g) →2ZnO(s) + 2SO₂(g)
The proper name for PCI6 is phosphorus hexachloride. Therefore it’s true
Answer:
Time (months) is the independent variable
Growth (measured) is the dependent variable.
Explanation:
Let y = growth
Let x = time
The result will yield a relation of the form
y = y(x), or y is a function of x.
x, the time can be controlled. The experimenter can decide how many months to conduct the experiment. It is the independent variable.
y, the growth is a response to the amount of time allowed for growth. It depends on x, therefore y is the dependent variable.