A. A pacemaker
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Answer:
Protons are located in the nucleus and have a positive charge and a mass of 1.
Explanation:
Know about protons, neutrons, and electrons.
Answer:
D. Electrical energy is changed into mechanical energy
Explanation:
When you turn on the fan, the electricity that is given through the power outlet allows the fan to have the available energy to spins the fan blades. By the fan's blades spinning, this is a movement that can be described as mechanical energy.
Answer: A
Explanation:
Hypothesis have to be based on previous knowledge and have to be able to be tested but the problem is most hypothesis can’t be explained so it’s impossible to prove a hypothesis correct because science uses inductive reasoning
Answer:
5.56 × 10⁻⁸
Explanation:
Step 1: Given data
- Concentration of the weak acid (Ca): 0.187 M
Step 2: Calculate the concentration of H⁺
We will use the following expression.
pH = -log [H⁺]
[H⁺] = antilog -pH = antilog -3.99 = 1.02 × 10⁻⁴ M
Step 3: Calculate the acid dissociation constant (Ka)
We will use the following expression.
![Ka = \frac{[H^{+}]^{2} }{Ca} = \frac{(1.02 \times 10^{-4})^{2} }{0.187} = 5.56 \times 10^{-8}](https://tex.z-dn.net/?f=Ka%20%3D%20%5Cfrac%7B%5BH%5E%7B%2B%7D%5D%5E%7B2%7D%20%7D%7BCa%7D%20%3D%20%5Cfrac%7B%281.02%20%5Ctimes%2010%5E%7B-4%7D%29%5E%7B2%7D%20%7D%7B0.187%7D%20%3D%205.56%20%5Ctimes%2010%5E%7B-8%7D)
