1. I don't understand what wave exercise waves are?
2. Water is the medium.
3. Air is the medium.
4. The Earth or ground is the medium.
(I think these are right, as the medium is what they are travelling through.)
Answer:
Scientists develop knowledge by making <u>observation</u> about the natural world that may lead to a scientific question.
A scientific question may lead to a(n) <u>hypothesis</u> which can be tested.
The results of <u>experimentation</u> can lead to changes in scientific knowledge.
Explanation:
In the process of developing scientific knowledge, scientists carry out series of observations on what happens in the natural world. This helps them to develop scientific questions. These scientific questions drawn can then lead to hypotheses which are testable.
The testing process leads to experimentation. It is in this process that much scientific questions receive answers. Testing actually lies at the core of scientific inquiry for all scientists. Whatever hypothesis made must always be tested.
The result of the testing or experimentation brings changes in scientific knowledge.
LD50 is defined as the lethal dose 50% which describes the amount of material required to kill 50% of the testing population. It is given in units of mg of chemical per kg of bodyweight of the recipient.
Comparing hydrogen peroxide and acetic acid, we see that peroxide has a lower LD50 of 900 mg/kg, with acetic acid having LD50 = 3310 mg/kg. When comparing LD50 values, the smaller value will be the more toxic compound. What this means is that in this case, a smaller amount of peroxide is required to kill 50% of the testing population compared to acetic acid.
Therefore, 3% hydrogen peroxide is more hazardous to consume.
Answer:
b) pH = 9.25
Explanation:
- NH4+(aq) + H2O(l) ↔ NH3(aq) + H3O+(aq)
- NH3 + H2O ↔ NH4+ + OH-
- 2 H2O ↔ H3O+ + OH-
⇒ Kb = [ NH4+ ] * [ OH- ] / [ NH3 ] = 1.86 E-5......from literature
mass balance NH4+:
⇒ M NH4+ = [ NH4+ ] - [ OH- ]
∴ [ NH3 ] ≅ M NH4+ = 0.26 M
⇒ Kb = (( 0.26 + [ OH- ] )) * [ OH- ] / 0.26 = 1.86 E-5
⇒ 0.26 [ OH-] + [ OH- ]² = 4.836 E-6
⇒ [ OH- ]² + 0.26 [ OH- ] - 4.836 E-6 = 0
⇒ [ OH- ] = 1.859 E-5 M
⇒ pOH = - Log ( 1.859 E-5 )
⇒ pOH = 4.7305
⇒ pH = 14 - pOH = 9.269
Answer: Aluminum reacts with oxygen to produce aluminum oxide as follows: 4Al + 3O2 → 2Al2O3 a.
Explanation: I really really <u>hope</u> that was <u>helpful.</u>
