Chemistry, 24.01.2020 05:31, scarlettp13

Zinc metal reacts with silver nitrate according to the reaction:

zn(s) + 2agno3(aq)zn(no3 )2 (aq) + 2ag(s)

calculate the mass of ag that forms when 3.00g of zinc metal is placed in an aqueous solution containing 3.75g of silver nitrate?

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2.38 grams of silver forms when 3.00g of zinc metal is placed in an aqueous solution containing 3.75g of silver nitrate.

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ ....(1)

$\text{Number of moles of zinc}=\frac{3.00g}{65g/mol}=0.0462mol$

$\text{Number of moles of silver nitrate}=\frac{3.75g}{170g/mol}=0.0220mol$

The chemical equation is:

$Zn(s)+2AgNO_3(aq)\rightarrow Zn(NO_3)_2(aq)+1Ag(s)$

By stoichiometry of the reaction;

2 moles of silver nitrate reacts with 1 mole of zinc

Thus 0.0220 moles silver nitrate react with= $\frac{1}{2}\times 0.0220=0.0110$ moles of zinc

Thus silver nitrate will acts as limiting reagent and zinc acts as excess reagent.

2 moles of silver nitrate produces 2 mole of silver

Thus 0.0220 moles silver nitrate react with= $\frac{2}{2}\times 0.0220=0.0220$ moles of silver

$0.0220mol=\frac{\text{Mass of silver}}{108g/mol}\\\\\text{Mass of silver}=2.38g$

Thus 2.38 grams of silver forms when 3.00g of zinc metal is placed in an aqueous solution containing 3.75g of silver nitrate.

answered: Guest

Answer: abeexplanation:

1. the question asks the most appropriate, which seems to rule out "all of the above." your choice appears to be the correct one.

2. the protocol described is good for identifying correlation, but not cause and effect. for cause/effect, you need to devise a protocol that will assign the treatment (or not) to groups that have essentially the same "demographics" with respect to all the other variables. your choice regarding control group seems appropriate. random assignment of treatment (choice d) may be appropriate also. (i think you can argue that b and d are just different descriptions of the same method.)

3. d will randomize the birds, but may not guarantee there are 10 in each group. e will do both, so seems the better choice.

comment on question 2

based on the problem statement, it seems clear that confident, attentive drivers are more likely to use daytime running lights. so, the protocol might need to be devised in such a way that the lights would be turned on or off without the driver's knowledge. (an attentive driver will figure it out.) assigning a confident, attentive driver to a group required to drive without running lights might mess with his/her confidence and attentiveness. you don't want your experiment to do that. (nor do you want the experiment to subject a driver to greater risk of accident as a consequence of driving without running lights.) experiments involving human safety are always problematic.

answered: Guest

the potential energy of the reactants is 200j.

from the energy diagram, the energy of the product formed is 350j; this means that, this reaction is an endothermic reaction, because it absorbs energy from its environment.