To solve this question, you must use the formula: q=mc(change in temperature), where q is heat, m is mass, C is specific heat and temperature change is temperature change. The specific heat for ice is 2.1kJ/Kg x K (given). The change in temperature is 15 degrees Celsius (which you should change to kelvins so you can cancel out units), or 273 + 15 = 288K. The mass is 150 grams, which is 0.15 kg. Now, we can solve for q, heat. We will do this by substituting variables into the formula. After simplifying and cancelling out units, the answer we get is: 90.72kJ.
Answer & Explanation:
The reason why is because global fossil fuel consumption is on the rise, and new reserves are becoming harder to find. Those that are discovered are significantly smaller than the ones that have been found in the past.
Oil: Consumption (Predictions): Over 11 Billion tonnes Annually. If we carry on as we are, our known oil deposits could run out in just over 53 years.
Gas (Predictions): If we increase gas production to fill the energy gap left by oil, our known gas reserves only give us just 52 years left.
Coal: Although it’s often claimed that we have enough coal to last hundreds of years, this doesn’t take into account the need for increased production if we run out of oil and gas, our known coal deposits could be gone in 150 years.
For example, oil reserves are a good example: 16 of the 20 largest oil fields in the world have reached peak level production – they’re simply too small to keep up with global demand.
During the year of 2015, fossil fuels made up 81.5% of total U.S. energy consumption. The number is most likely increasing every year.
(fyi: the graph provided is showing future energy reserves for coal, gas and oil. approxiamately.)
Answer:
2.04 x 10²⁴ molecules
Explanation:
Given parameters:
Mass of Be(OH)₂ = 145.5g
To calculate the number of molecules in this mass of Be(OH)₂ we follow the following steps:
>> Calculate the number of moles first using the formula below:
Number of moles = mass/molarmass
Since we have been given the mass, let us derive the molar mass of Be(OH)₂
Atomic mass of Be = 9g
O = 16g
H = 1g
Molar Mass = 9 + 2(16 + 1)
= 9 + 34
= 43g/mol
Number of moles = 145.5/43 = 3.38mol
>>> We know that a mole is the amount of substance that contains Avogadro’s number of particles. The particles can be atoms, molecules, particles etc. Therefore we use the expression below to determine the number of molecules in 3.38mol of Be(OH)₂:
Number of
molecules= number of moles x 6.02 x 10²³
Number of molecules= 3.38 x 6.02 x 10²³
= 20.37 x 10²³ molecules
= 2.04 x 10²⁴ molecules
Answer:
C
Explanation:
As the temperature increases, the kinetic energy of the molecules increases.
The answer is NO. During combustion of hydrogen, water is produced as an end product. The chemical formulae for combustion of hydrogen are:
2H2 + O2 -->2 H2O
another advantage is that the whole of the fuel load is combusted hence little wastage. This has made the fuel advantageous in its use as rocket fuel since there is no baggage fuel.
