<span>The half-life of 9 months is 0.75 years.
2.0 years is 2.0/0.75 = 2.67 half-lives.
Each half-life represents a reduction in the amount remaining by a factor of two, so:
A(t)/A(0) = 2^(-t/h)
where A(t) = amount at time t
h = half-life in some unit
t = elapsed time in the same unit
A(t)/A(0) = 2^(-2.67) = 0.157
15.7% of the original amount will remain after 2.0 years.
This is pretty easy one to solve. I was happy doing it.</span>
A general equation for a combustion reaction would be expressed as follows:
CxHy + (x+y/2)O2 = xCO2 + y/2H2O
Propane would obviously would only have carbon and hydrogen in its structure. Assuming a complete combustion, all of the carbon atoms would go to carbon dioxide and all of the hydrogen atoms to water. To determine the empirical, we determine the number of carbon and hydrogen atoms present.
moles C = 2.461 g CO2 ( 1 mol / 44.01 g ) ( 1 mol C / 1 mol CO2 ) = 0.06 mol C
moles H = 1.442 g H2O ( 1 mol / 18.02 g ) ( 2 mol H / 1 mol H ) = 0.16 mol H
Then, we divide the smallest amount to the each mole of the atoms. We do as follows:
C = 0.06 / 0.06 = 1
H = 0.16 / 0.06 = 2.67
Then we multiply a number in order to obtain a whole number ratio between the atoms.
1 CH2.67
2 C2H5.34
3 C3H8 <-------- empirical formula
Explanation:
Molar mass of HBr = 81 g/mol
Molar mass of nitrogen dioxide gas = 46 g/mol
Molar mass of ethane = 30 g/mol
Graham's Law states that the rate of effusion or diffusion of gas is inversely proportional to the square root of the molar mass of the gas. The equation given by this law follows the equation:
So, the gas with least molar mass will effuse out fastest from the container and that is ethane gas.
The formula for average kinetic energy is:
where,
k = Boltzmann’s constant = 
T = temperature = 273.15 K ( at STP)
As we can see from the formula that kinetic energy depends upon only temperature of the gas molecule.
So, from this we can say that all the gas molecules have the same average kinetic energy at this temperature.
Answer:
Explanation:
In this chemistry lab, students investigate how to build and launch a simple rocket that uses hydrogen and oxygen gases that will be mixed to propel the rocket (large bulb plastic pipette). Students will understand the principles of combustion reactions, kinetics, stoichiometry of reactions, activation energy, explosive mixtures, rocketry, and different types of chemical reactions. Students will explore and determine the proportions of hydrogen and oxygen mixture that will achieve the best launch results. Students will compare the balanced chemical reaction of hydrogen and oxygen with their lab results; students should discover that the optimal distance occurs when the mixture of hydrogen and oxygen is two to one hydrogen, oxygen mixture ratio and this can be determined theoretically from the balanced chemical reaction equation. Students will perform the lab, collect data, and discuss, compare, and contrast their lab findings with the balanced chemical reaction equation. Students will present their structured inquiry investigations using a power-point presentation. Other groups along with the teacher will assess each group by using a provided rubric. Group assessments will be the deciding assessment for the final lab score. A follow up activity could investigate how NASA scientists launch real rockets into space and propose a procedure to investigate and collect data on a launching a heavier object at the school football field.
Answer:
In general, liquids tend to get “thinner” when their temperature increases. For example, honey and oil tend to flow better at higher temperatures. Therefore, increasing temperature decreases viscosity. In general, the liquids tend to expand when their temperature increases
Explanation:
