Answer:
- <em>The substance that cannot be broken down by a chemical change is </em><u>tungsten (option C)</u>
Explanation:
Chemical compounds are pure <em>substances</em> constituted by two or more different elements. They have fixed composition and have their unique chemical properties, different from their individual components (elements) and from other compounds.
Thus chemical compounds can<em> be broken down by a chemical change</em> into their individual atoms or other simpler compounds.
The substances indicated by the choices <em>A) methane, B) propanal, and D) water</em>, are chemical compounds with chemical formulae CH₄, C₃H₆O, and H₂O, respectively, so they<em> can be broken down into their consitutents by a chemical change</em>.
On the other hand, <em>tungsten</em> is one of the 118 known elements. Its atomic number is 74, and its chemical symbol is W.
Then, being tungsten an element, which means that all the atoms present in a pure sample have the same number of protons and electrons, it <em>cannot be broken down by a chemical change</em>. The only way to split an atom of tungsten is by a nuclear reaction.
C. the CO3 in limestone (CaCO3) will nuetralize the acid
Answer:
The enthalpy of neutralization and its relation to esterification is explained below in details.
Explanation:
The conventional enthalpy variation of neutralization is the enthalpy exchange when extracts of an acid and an alkali respond together under conventional circumstances to generate 1 mole of water. Remark that the enthalpy change of neutralization is always estimated per mole of water produced.
Answer:
XeF₂
Explanation:
Let's call the compound as XeaFb, where a and b are the number of atoms of each element. In the beginning, the partial pressure of XeaFb was 16 torr. By Dalton's Law, the total pressure of a gas mixture is the sum of the partial pressures of the components, so:
pH₂ = 64 - 16 = 48 torr
The reaction that happened was:
XeaFb + (b/2)H₂ → aXe + bHF
The stoichiometry of the reaction is 1:b/2:a:b. If all the XeaFb reacts:
1 torr of XeaFb -------- b/2 torr of H₂
16 torr -------- x
By a simple direct three rule:
x = 16b/2 = 8b torr of H₂ reacts
1 torr of XeaFb -------- a torr of Xe
16 torr -------- x
x = 16a torr of Xe is formed
Thus, 8b + 16a = 32
b + 2a = 4
The empirical formula is the minimum integer number of the elements in the compound. So, let's suppose a = 1 because fluorine can do only one bond, thus it's unprovable that will be more than one Xe bonded with one F:
b + 2*1 = 4
b = 2
Thus, the empirical formula is XeF₂.