7. an unknown metal was reacted with 20 ml of 2.0 m hcl to produce hydrogen gas that was
collected over water. assume that no air was present initially in the container used to collect the
hydrogen. using the data provided in option_ g determine the formula of the metal
chloride that is formed. show all of your work. (hint: consider the significance of
coefficients in a balanced equation. start by writing an unbalanced equation using m to
represent the metal and mci, to represent the metal chloride. then use the data given to
determine the ratio of moles of metal to moles of hydrogen and complete the balanced equation.)

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)

answer: a tank of height h is filled with water and sits on the ground. water squirts from a hole at a height y above the ground and has a range r. for two y values, 0 and h, r is zero. determine the value of y for which the range will be a maximum.

explanation:

the awnser is group 12

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol