Answer:
When a Magnesium Ribbon is burnt, a powdery substance called magnesium oxide is formed.
Explanation:
There has obviously been a chemical change because several chemical properties of the magnesium have been modified: the color, the texture and the mass.
The increase in mass is due to the fact that oxygen from the air has combined with the magnesium to make magnesium oxide, MgO.
The chemical equation, Mg + O2 MgO shows this reaction but it needs to be balanced to make 2Mg + O2 2MgO.
Using stoichiometry, we can convert this eqation into an equation with moles:
2 mol Mg + 1 mol O2 2 mol MgO.
Next, we convert to grams using atomic masses obtained from the periodic table:
48g Mg + 32g O2 80g MgO
Lastly, we determine the same thing in the proportions we used. In other words, we used only 0.15g of Mg (not 48g) so everything needs to be divided by 320. So 80 / 320 = 0.25 g. If we burn 0.15 g of Mg, we obtain 0.25 g of MgO.
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This is my first answer.
I think it's true look at the picture
A combustion reaction involves an organic compound reacted with oxygen. The general chemical equation is as follows:
<span>
Organic Compound + Oxygen = CO2 + H2O
</span><span>To calculate the amount of C present in the original sample, we use the values given and assume that there is complete combustion that is happening.
</span><span>
7.33 g CO2 ( 1 mol CO2 / 44.01 g CO2)(1 mol C / 1 mol CO2) = 0.167 mol C
Therefore, 0.167 mol of C was originally in the sample.</span>
Gas particles are small and the total volume occupied by gas molecules is negligible relative to the total volume of their container. ... The average kinetic energy of gas particles is proportional to the absolute temperature of the gas, and all gases at the same temperature have the same average kinetic energy
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Answer
7665 years
Procedure
Let N₀ be the amount of carbon-14 present in a living organism. According to the radioactive decay law, the number of carbon-14 atoms, N, left in a dead tissue sample after a certain time, t, is given by the exponential equation:
N = N₀e^(-λt)
where λ is the decay constant which is related to half-life (T1/2) by the equation:
Here, ln(2) is the natural logarithm of 2.
The percent of carbon-14 remaining after time t is given by N/N₀.
Using the first equation, we can determine λt.
The half-life of carbon-14 is 5,720 years, thus, we can calculate λ using the second equation, and then find t.
Solving the second equation for t, and using the λ we have just calculated we will have
t= 7665 years
