Four different compounds can be formed by reacting $2470\mathrm{.}40g$ of oxygen. a$)$ Calculate the mass of oxygen per grams o your results based on the atomic theory?

$g,28\mathrm{.}16g,56\mathrm{.}32g,$ or

$0\mathrm{.}840g$ of a compound $(C_x{H}_y{O}_z)$ is combusted entirely and formed $1\mathrm{.}944g$ of carbon dioxide and $0\mathrm{.}400g$ of water. What is the empirical formula of this compound $(C_x{H}_y{O}_z)?$

b$)$ How can you justify

a$)$ Let's assume that you have two solutions of NaCl in two different beakers. One of them contains $20mL$ of $0\mathrm{.}800M$ of NaCl and the others has $60mL$ of $0\mathrm{.}640M$ of NaCl. After mixing these solution, the total volume is brought to $40mL$ by evaporation. What is the final concentration of NaCl $?$

b$)$ A scientist would like to determine the mass percentage of chloride ion in seawater. She took $30\mathrm{.}10mL$ sample of seawater from the sea. After the titration of seawater with $0\mathrm{.}3357M$ silver nitrate, solid silver chloride was formed, and the volume of silver nitrate used in titration was found to be $38\mathrm{.}02mL.$ If the density of seawater is $1025m\frac{g}{m}L,$ what is the mass percentage of chloride ion in the seawater?

c$)$ Write value of the angles indicated in the figure