What question are you talking about?
Answer: The half-life of a first-order reaction is, 
Explanation:
All the radioactive reactions follows first order kinetics.
Rate law expression for first order kinetics is given by the equation:
![k=\frac{2.303}{t}\log\frac{[A_o]}{[A]}](https://tex.z-dn.net/?f=k%3D%5Cfrac%7B2.303%7D%7Bt%7D%5Clog%5Cfrac%7B%5BA_o%5D%7D%7B%5BA%5D%7D)
where,
k = rate constant = ?
t = time taken = 440 s
![[A_o]](https://tex.z-dn.net/?f=%5BA_o%5D)
= initial amount of the reactant = 0.50 M
[A] = left amount = 0.20 M
Putting values in above equation, we get:
The equation used to calculate half life for first order kinetics:
Putting values in this equation, we get:
Therefore, the half-life of a first-order reaction is,
Answer:
2 PO₄³⁻(aq) + 3 Fe²⁺(aq) ⇒ Fe₃(PO₄)₂
Explanation:
Let's consider the complete ionic equation between the ions present. It includes all the ions and the insoluble compounds (Fe₃(PO₄)₂ is insoluble).
Na⁺(aq) + 2 PO₄³⁻(aq) + 3 Fe²⁺(aq) + NO₃⁻(aq) ⇒ Fe₃(PO₄)₂ + Na⁺(aq) + NO₃⁻(aq)
The net ionic equation includes only the ions that participate in the reaction (not spectator ions) and the insoluble compounds.
2 PO₄³⁻(aq) + 3 Fe²⁺(aq) ⇒ Fe₃(PO₄)₂
Answer:
Progress made in Asia and the Middle East is clear, with nations such as China, Singapore and Malaysia all demonstrating increased adaptability. Much of Africa has also made progress since 1995, along with South American nations, including Brazil and Chile.
Answer:
C. A ball dropped from a height of 10 m will hit the ground at a higher speed than an identical ball dropped from a height of 5 m.
Explanation:
The statement of the hypothesis is that " the greater the height from which you drop a ball, the faster the ball will be traveling when it hits the ground because gravity has more time to speed it up ".
The hypothesis statement is quite explicit. We can deduce that objects at a higher height above the ground will hit the ground much more faster and harder compared to those at a shorter height.
A ball at height of 10m is expected to drop with a higher speed on the ground compared to an identical ball at a height of 5m.
If the balls are at the same height, they are expected to fall with the same speed so far they are identical. Also, a ball at a shorter height will fall at a lower speed.
