Question

3 multiple choice 1 point which of these is an compound? sodium hydroxide, naoh tea shampoo copper, cu 4 formula 1 point a gas has a pressure of 749.9 mm hg at 12.5 °c. what is the temperature, in °c, at a pressure of 634.0 mmhg? round your answer to 1 decimal place. answer 5 multiple choice 1 point what is the definition of volume? the average kinetic energy of particles. force applied per unit area. the relative size of particles. the amount of space a substance occupies.

Explanation:

Question 3

A compound is a substance made up of two or more different elements chemically combined. Sodium hydroxide (NaOH) is composed of sodium (Na), oxygen (O), and hydrogen (H). Tea and shampoo are mixtures, and copper (Cu) is an element.

Step1: Convert initial temperature to Kelvin

The initial temperature $T_1 = 12.5+273.15=285.65$ K. According to Gay - Lussac's law $\frac{P_1}{T_1}=\frac{P_2}{T_2}$.

Step2: Rearrange the formula to solve for $T_2$

$T_2=\frac{P_2T_1}{P_1}$. Substitute $P_1 = 749.9$ mmHg, $T_1 = 285.65$ K, and $P_2 = 634.0$ mmHg into the formula.
$T_2=\frac{634.0\times285.65}{749.9}\approx242.7$ K.

Step3: Convert $T_2$ back to Celsius

$T_2$ in Celsius is $242.7 - 273.15=-30.5$ °C.

Volume is defined as the amount of space a substance occupies. The average kinetic energy of particles is related to temperature, force applied per unit area is pressure, and the relative size of particles is not the definition of volume.

Answer:

A. sodium hydroxide, NaOH

Question 4