1. How does Magnesium form a 2+ ion while sulfur forms a 2- ion? 2. Express 85.0
ID: 1003222 • Letter: 1
Question
1. How does Magnesium form a 2+ ion while sulfur forms a 2- ion?
2. Express 85.0miles per hour in meters per minute ( 1 km = .60mi) Prove calculations
3.Calculate the energy required to heat a 355g smaple of silver (Cp = .235J/g ceclsius) From 25.5 to 45.5 degrees celsius. prove calculations
4. Two objects of different composition with the same mass are painted black and placed in the sun at the same time . After 10 mins object B is hotter than A . Which has the higher specific heat ? Explain why.
5 Gold has a density of 19.3 g/cm^3. if a chain necklace has mass of 605g and volume of 42.7cm^3, is the chain pure old? prove calculatons.
6. Why arent significant figures applicable in math class?
7. Give 2 parts of Daltons atomic theory. What errors did he make , what do we know to be different. Give 2.
8.
Explanation / Answer
Solution:
1) The group number for a metal generally equals the positive charge on the cation. Metals like Li, Na and K in group 1A typically form ions with a +1 charge.
Calcium and magnesiun have two valence or outer electrons. The energy needed to remove these electrons is usually available in chemical reactions with nonmetals. The removal of a third electron requires more energy than is available in chemical reactions.
2) 85 miles/hr ---> ? m/mts
1 mile = 1609.34 metres and 1 hr = 60 mts
85 miles/hr * 1609.34 metres/miles * hr/60 mts
= 2279.898 metres/minute
3) q = mCp(T2-T1)
= 355 * 0.235 * (45.5-25.5)
= 1668.5 J
= 1.669 kJ
4) Specific heat is the amount increased by each degree of temperature for the given condition specific heat of object A is higher on comparing to B as its getting hot earlier than A.
5) density = mass/volume
= 605/42.7
= 14.2 g/cm3 by comparing with given density of 19.3 g/cm3 the chain is not pure and is mixed with other substances.
6) Significant figures are used to minimize the errors in experiments. In Physics are chemistry, we conduct a lot of experiments with high chances of errors. And for calculating with those, if you use all digits, you may make be very deviated from the actual answer.
In math class, we don't calculate results from experiments. So it's not required to use significant figures.
7) Dalton theory:
Drawbacks of Dalton theory:
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