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pentagon [3]
3 years ago
14

Try try try please for me please

Chemistry
1 answer:
Inga [223]3 years ago
8 0

Answer:

a.) It is a chemical reaction because a new substance was formed and a colour change occurred in the reaction.

b.) Iron- Metallic element

sulpher- Non-Metalic element

Iron Sulphide- Compound

HOPE IT HELPS....

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A sample of gas at 25ºc has a volume of 11 l and exerts a pressure of 660 mm hg. how many moles of gas are in the sample?
san4es73 [151]
  The  moles of  the gas    in the sample  is 0.391  moles

    calculation
by use  of  ideal  gas  equation, that  is Pv=nRT
where  n  is number  of moles
           P(pressure)= 660  mmhg
           R(gas  constant)  =  62.364 l.mmhg/mol.K
           T(temperature)= 25 +273 =   298 k

by  making  n  the subject of the  formula

n= Pv/ RT

n is therefore=   (660mm hg  x11 L)/(  62.364 L.mmhg/mol.k  x298 K)  = 0.391  moles
5 0
4 years ago
The combustion of 0.374 kg of methane in the presence of excess oxygen produces 0.983 kg of carbon dioxide. What is the percent
anyanavicka [17]
Assuming that the combustion formula is
CH4 + 2O2 --> 2H2O + CO2<span>,

That means for every 1 molecule of methane(CH4) there will be one molecule of carbon dioxide(</span>CO2) produced. Methane molecular weight 16, carbon dioxide molecular weight is 44. Then the percent yield should be:
1 * (0.374/ 16) /(0.983/44)= 0.374*44/ 0.983 * 16= 104.6%

You sure the number is correct? Percent yield should not exceed 100%
5 0
4 years ago
the pressure on 2.50L of N20 changes from 105 kPa to 40.5 kPa. if the temperature does not change, what will the new volume be.
tresset_1 [31]

Answer:

6.48L

Explanation:

Given parameters:

V₁ = 2.5L

P₁  = 105 kPa

P₂  =  40.5 kPa

Condition: constant temperature

Unknown:

V₂  = ?

Solution:

To solve this problem, we are considering pressure and volume relationship. This should be solved by applying the knowledge of Boyle's law.

The law states that "The volume of fixed mass of a gas varies inversely as the pressure changes if the temperature is constant".

Mathematically;

                     P₁V₁  = P₂V₂

where P and V are pressure and volume, 1 and 2 represents initial and final states.

Substitute to find the V₂;

                  105 x 2.5  = 40.5 x  V₂

        Solving for V₂ gives 6.48L

6 0
3 years ago
1.
snow_tiger [21]
There are 1,000m is 1k. So just move the decimal one position right. 127.56m

There are 10,000cm in 1k. Move the decimal two positions right. 1275.6cm
5 0
4 years ago
G.com what is the mass of a gold bar that is 7.379 × 10–4 m3 in volume
tiny-mole [99]
<span>7.379 * 10^(-4) is measured, hence prone to error, either human error or via measuring device. In this case,
100 cm = 1 m is written in stone and is unquestionable.
 The density of the gold is 19.3 g/cm^3 and could be an approximation.
 The approximation is good to at least one night.</span>
5 0
3 years ago
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