answer:To find the percent composition by mass for each element in a compound, you need to follow these steps: 1. Find the molar mass of the compound by summing the atomic masses of all the atoms present. 2. Divide the total mass of each element in one mole of the compound by the molar mass. 3. Multiply by 100 to get the percentage. I'll provide this information for each of the compounds you've asked about. **Sodium Phosphate (Na3PO4):** 1. Calculate the molar mass of Na3PO4: - Na: 22.99 g/mol x 3 = 68.97 g/mol - P: 30.97 g/mol x 1 = 30.97 g/mol - O: 16.00 g/mol x 4 = 64.00 g/mol - Total molar mass = 68.97 + 30.97 + 64.00 = 163.94 g/mol 2. Calculate the percent composition of each element: - Percent Na = (68.97 g/mol / 163.94 g/mol) x 100 = 42.06% - Percent P = (30.97 g/mol / 163.94 g/mol) x 100 = 18.89% - Percent O = (64.00 g/mol / 163.94 g/mol) x 100 = 39.05% **Hydrogen Peroxide (H2O2):** 1. Calculate the molar mass of H2O2: - H: 1.008 g/mol x 2 = 2.016 g/mol - O: 16.00 g/mol x 2 = 32.00 g/mol - Total molar mass = 2.016 + 32.00 = 34.016 g/mol 2. Calculate the percent composition of each element: - Percent H = (2.016 g/mol / 34.016 g/mol) x 100 = 5.93% - Percent O = (32.00 g/mol / 34.016 g/mol) x 100 = 94.07% **Carbon Dioxide (CO2):** 1. Calculate the molar mass of CO2: - C: 12.01 g/mol x 1 = 12.01 g/mol - O: 16.00 g/mol x 2 = 32.00 g/mol - Total molar mass = 12.01 + 32.00 = 44.01 g/mol 2. Calculate the percent composition of each element: - Percent C = (12.01 g/mol / 44.01 g/mol) x 100 = 27.29% - Percent O = (32.00 g/mol / 44.01 g/mol) x 100 = 72.71% **Carbon Monoxide (CO):** 1. Calculate the molar mass of CO: - C: 12.01 g/mol x 1 = 12.01 g/mol - O: 16.00 g/mol x 1 = 16.00 g/mol - Total molar mass = 12.01 + 16.00 = 28.01 g/mol 2. Calculate the percent composition of each element: - Percent C = (12.01 g/mol / 28.01 g/mol) x 100 = 42.91% - Percent O = (16.00 g/mol / 28.01 g/mol) x 100 = 57.09% Please note that the atomic masses used here are to the correct number of significant figures as typically found on the periodic table, and percent compositions are given to two decimal places. If you need a different level of precision, you may need to adjust the calculations accordingly with more precise atomic masses.

answer:Ethos, logos, and pathos are three modes of persuasion used to convince audiences. They are often employed in rhetoric, argumentation, and public speaking. The concepts were developed by the ancient Greek philosopher Aristotle in his work "Rhetoric." Here's a breakdown of each: 1. **Ethos (Ethical Appeal):** Ethos refers to the credibility, character, and reliability of a speaker or writer. Establishing ethos means the audience perceives the speaker as trustworthy, knowledgeable, and having the appropriate authority or expertise on the subject at hand. An argument grounded in ethos might emphasize the speaker's qualifications, reputation, and ethics. Example: A doctor discussing health issues would have strong ethos in the context of medical advice, given their professional experience and education. 2. **Logos (Logical Appeal):** Logos is the appeal to logic and reason. It involves constructing a clear, reasoned argument with evidence and facts to support one's case. Logos seeks to persuade by presenting logical arguments that are coherent and supported by data, statistics, or factual information. It appeals to the audience’s rationality. Example: In a scientific debate, a speaker using logos might cite numerous studies and expert testimonies to back up their claims. 3. **Pathos (Emotional Appeal):** Pathos appeals to the emotions, values, desires, and hopes of the audience, or on the other hand, plays on their fears, prejudices, and irrational behaviors. It is a way to connect with the audience on an emotional level, which can be a powerful means of persuasion. While ethos and logos appeal to ethics and logic, pathos appeals to the heart. Example: A charity organization might use images of people in need and tell heartfelt stories to evoke empathy and compassion from potential donors. Effective communication or argument often uses a combination of ethos, logos, and pathos. Depending on the context and the audience, a speaker or writer may lean more heavily on one mode over the others, but incorporating all three can provide a well-rounded and compelling argument.

answer:To find out the percent composition of each element in the new compound (rust), we first need to know the total mass of the compound. The compound is formed by the reaction of iron (Fe) with oxygen (O). Given: - Mass of iron (Fe): 1.26 g - Mass of oxygen (O): 0.54 g First, determine the total mass of the compound (rust): Total mass = mass of Fe + mass of O = 1.26 g + 0.54 g = 1.80 g Next, calculate the percent composition of each element: - Percent composition of iron (Fe) in the compound: [ text{Percent Fe} = left( frac{text{mass of Fe}}{text{total mass of compound}} right) times 100 ] [ text{Percent Fe} = left( frac{1.26 text{ g}}{1.80 text{ g}} right) times 100 ] [ text{Percent Fe} ≈ 70.00% ] - Percent composition of oxygen (O) in the compound: [ text{Percent O} = left( frac{text{mass of O}}{text{total mass of compound}} right) times 100 ] [ text{Percent O} = left( frac{0.54 text{ g}}{1.80 text{ g}} right) times 100 ] [ text{Percent O} ≈ 30.00% ] Thus, the percent composition of iron in the rust compound is approximately 70.00%, and the percent composition of oxygen is approximately 30.00%. These percentages are rounded to the nearest two decimal places as per the significant figures given in the problem statement.

answer:The word "necessary" in the Preamble to the Declaration of Independence is being used to express an obligation or a need that cannot be avoided. It is stating that there comes a time when a group of people must sever their political ties with another governing body because it's essential for them to take their own place as an independent and equal entity. This action is not a matter of choice but of compelling obligation based on the inherent rights of the people. Summary of the Sentence: The sentence containing "necessary" explains that when it comes to a point in history where a group of people must disconnect from a political relationship to become independent, they are obligated to explain the reasons for this separation to the rest of the world, out of respect for global opinion. The word "necessary" is crucial to the Preamble because it conveys the gravity and inevitability of the decision to declare independence from Great Britain. The colonists are framing their separation as a requirement imposed by natural law and divine providence, not as a decision made lightly or without serious cause. It underscores the message that the move towards independence is justified, reasonable, and rooted in the pursuit of natural rights, and it is not merely a preference or a rash act of rebellion.