1) Calcium carbonate comprises 40.0% calcium by weight.
M(CaCO₃)=100.1 g/mol
M(Ca)=40.1 g/mol
w(Ca)=40.1/100.1=0.400 (which is 40.0%)!
2) The mass fraction mentioned is superfluous information.
3) The resulting solution is:
m(Ca)=1.2 g
m(CaCO₃)=M(CaCO₃)*m(Ca)/M(Ca)
m(CaCO₃)=100.1g/mol*1.2g/40.1g/mol=3.0 g
Answer:
710.33 g NO2
Explanation:
2 C8H18 + 25 O2 → 16 CO2 + 18 H2O
(800 g octane) / (114.2293 g C8H18/mol x (25/2)) = 87.54 mol O2 utilized for combusting octane
= 15.44 mol O2 used for generating NO2
O2 + 2NO → 2NO2
(15.44 mol O2) x (2/2) x (46.0056 g NO2/mol) = 710.33 g NO2
Answer:
- A. Which element, X or Z, has a higher molar mass?
Explanation:
Heating the original compounds intensely to remove all oxygen causes chemical decomposition reactions:
- 2XClO₃ (solid) → 2XCl + 3O₂ (gas)
- 2ZClO₃ (solid) → 2ZCl + 3O₂ (gas)
By measuring the initial mass of each sample and the mass remaining after heating, the student can compute the oxygen gas mass released:
- Mass of oxygen released = initial sample mass minus residue mass
Using this oxygen mass, she can calculate how many moles of oxygen were present in each sample:
- Moles of oxygen = oxygen mass (g) divided by molar mass of oxygen
Next, the moles of the original sample are determined:
- Each mole of XClO₃ or ZClO₃ has 3 moles of oxygen atoms.
So, dividing the moles of oxygen released by 3 gives the moles of the sample.
Applying the formula molar mass = mass / moles, the student finds the molar masses of XClO₃ and ZClO₃.
Thus, this data allows answering question A: Which of X or Z has the higher molar mass?
True; True; False; True; True. Explanation: Organic compounds can exist in pure form, but they are typically found in mixtures, such as in petroleum, which implies that the compound one obtains could be impure. Organic compounds can exist in three states: solid, liquid, or gas. The state depends on the molecular forces and the molar mass involved. For instance, at room temperature, gasoline is a liquid, natural gas is a gas, and glucose is a solid. The fundamental characteristic of organic compounds is that they contain carbon (C) and hydrogen (H), while other elements like oxygen (O), nitrogen (N), halogens, and sulfur (S) may or may not be part of their structure. Because carbon can form chains, millions of organic compounds are known. Spectroscopic methods can provide information such as composition, molar mass, and diffraction patterns, which can assist in identifying certain chemical properties and may require additional identification tests.
Oxygen and Nitrogen are the most alike among the listed elements due to their proximity in the periodic table. While this reasoning may not be particularly robust, these two elements share certain similarities. They are both classified as non-metals, exhibit high electronegativity, exist as diatomic gases in their elemental forms, contain a similar number of valence electrons, and generally act as oxidizing agents. Although Oxygen and Chlorine also show similarities, they are not as closely related as Oxygen and Nitrogen.
