I would say that it would be excessive rain and heat. Because, after a drought and a flood happen, standing water is home to mosquitos which carry malaria. I hope this helps!
Answer: El HEXAHIDRATO DE SULFATO DE NÍQUEL es incompatible con ácidos fuertes, azufre, Ni (NO3) 2, madera y otros combustibles. (NTP, 1992) A temperatura elevada sufre una reacción violenta con aluminio o magnesio en polvo. Cuando se calienta hasta la descomposición emite humos muy tóxicos de óxidos de azufre
Explanation:
Answer:
scientists often communicate their research results in three general ways:
1) One is to publish their results in peer-reviewed journals that can be ready by other scientists.
2) Two is to present their results at national and international conferences where other scientists can listen to presentations
Explanation:
<span>Suda karıştırıldıysa, kaynatma ile hacmi azaltmayı deneyebilirsiniz, ancak bir veya daha fazla çözüm bulunmaması durumunda çok uzun sürecektir. Çözeltiye fazla aseton ilavesi, filtrelenebilen tuzu çöktürmelidir. Asetondan buharlaşma şeker üretecektir.</span>
Answer:
- <u><em>It is positive when the bonds of the product store more energy than those of the reactants.</em></u>
Explanation:
The <em>standard enthalpy of formation</em>, <em>ΔHf</em>, is defined as the energy required to form 1 mole of a substance from its contituent elements under standard conditions of pressure and temperature.
Then, per defintion, when the elements are already at their standard states, there is not energy involved to form them from that very state; this is, the standard enthalpy of formation of the elements in their standard states is zero.
It is not zero for the compounds in its standard state, because energy should be released or absorbed to form the compounds from their consituent elements. Thus, the first choice is false.
When the bonds of the products store more energy than the those of the reactants, the difference is:
- ΔHf = ΔHf products - ΔHf reactants > 0, meaning that ΔHf is positive. Hence, the second statement is true.
Third is false because forming the compounds may require to use (absorb) or release (produce) energy, which means that ΔHf could be positive or negative.
Fourth statement is false, because the standard state of many elements is not liquid. For example, it is required to supply energy to iron to make it liquid. Thus, the enthalpy of formation of iron in liquid state is not zero.
