CHEMISTRY HIGH SCHOOL

When was tin discovered tin is an element please help 75 pts

Answers

Answer 1
Answer:  It was used from the Bronze Age(3000 BC) and tin was used in the bronze. 

Related Questions

In a coffee-cup calorimeter, 100.0 ml of 1.0 m naoh and 100.0 ml of 1.0 m hcl are mixed. both solutions were originally at 24.68c. after the reaction, the final temperature is 31.38c. assuming that all the solutions have a density of 1.0 g/cm3 and a specific heat capacity of 4.18 j/8c ? g, calculate the enthalpy change for the neutralization of hcl by naoh
The action of some commercial drain cleaners is based on the following reaction: 2 NaOH(s) + 2 Al(s) + 6 H2O(l) → 2 NaAl(OH)4(s) + 3 H2(g) What is the volume of H2 gas formed at STP when 6.32 g of Al reacts with excess NaOH?
19 An effective collision between reactant particles requires the particles to have the proper(1) charge and mass(2) charge and orientation(3) energy and mass(4) energy and orientation
What would indicate that a physical change takes place when copper is drawn into wire?
Which of the following materials is not considered to be a semiconductor? germanium tin silicon aluminum

An organic molecule is likely to contain all of these elements except: Answer C H O Ne N

Answers

Organic molecules typically do not contain the noble gases, so they would contain all but Ne

Describe how to properly measure the volume of a liquid.

Answers

Use a graduated cylinder.
The best way to measure it usually is to use a beaker or graduated cylinder. 

How do you find a Oxidation number

Answers

An oxidation number is the charge of the ion that would form if a covalent molecule was ionic. Oxidation numbers exist for covalent compounds, as ions are not formed.

The oxidation number is determined by the respective electronegativity of the atoms involved. A more electronegative element will always have a negative oxidation number. In the compound, all the oxidation numbers must add up to 0. Oxidation numbers of elements can vary between compunds.

A few rules to follow about oxidation numbers
Fluorine will always be -1
Oxygen will be -2 unless in a compound with fluorine
Hydrogen is usually +1

A few examples
HF (Hydrogen flouride) Oxy number of H= +1 and F = -1

H2O Oxy number of H = +1  and O= -2

NH3 Oxy of H= +1 and since there are 3 Hydrogens each with an oxidation number of +1 N must have an oxy number of -3 for the overall oxidation number of the compound to be 0.  

H2SO4 Oxy number of H= +1 O=-2 When adding up the hydrogen and oxygen oxidation numbers ( 1 + 1 -2 - 2 -2 -2) we are left with -6 thus S must have an oxidation number of +6 for the overall number to be 0. 

NO2 Oxidation number of O= -2 there are 2 oxygens leaving us with -4 thus N must have an Oxy number of +4 for the overall number to be 0.

What structure does a eukaryotic cell have that a prokaryotic cell does not?

Answers

The answer is a Nucleus. Eukaryotic cells have nuclei while;e prokaryotic cells do not.

When a substance dissolves, it undergoes a _____.

Answers

The right answer is physical change.

In the general sense, dissolution is the action of dissolving something, that is to say, of decomposing it by the separation of its parts.

In chemistry, dissolution is an intimate mixture of two bodies, at least one of which is liquid.

Eg: the dissolution of sugar in the water, the sugar will pass from the solid and dry state to the dissolved state so there is a physical change. The sugar is going to be surrounded by water molecules and form hydrogen bonds, so it can be a chemical change.
2 types of changes
physical change
chemical change

the easy way to tell the difference is
a physical change is genrally reversable
it changes the look but not the composition
for example, water freezes into ice is physical change

a chemical change is generally not reversable (easily)
ex metal rusting, egg rotting
it changes theh composition itself


when a substance disolves, it actually merges and the molecules move around and sometimes bond
so it's a chemical change

What is the concentration of a 450 mL solution that contains 200 g of FeCl2?

Answers

Molar mass FeCl₂ = 126.751 g/mol

450 mL / 1000 = 0.45 L

1 mole ------- 126.751 g
? mole ------- 200 g

moles = 200 * 1 / 126.751

moles = 200 / 126.751

= 1.57789 moles FeCl₂

M = n / V

M = 1.57789 / 0.45

= 3.50 Mol/L or M

hope this helps!
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