Explanation:
the physical and chemical properties of an element are periodic functions of their atomic number.
a) The reaction is exothermic since the overall enthalpy change is negative. this means that the system has lost energy to the environment, namely, the apparatus and due to drought.
b) We first calculate the number of moles in 3.55 grams of magnesium.
number of moles= mass/ atomic mass
=3.55/24
=0.1479 moles(to 4sf)
now, if 2 moles of magnesium give -1204kJ
How much energy is given by 0.1479 moles
= (0.1479×-1204kJ)
=-89.0358kJ (don't forget the negative sign)
c) two molesof MgO produces -1204kJ of energy
then -234kJ will be produced by
=(-234kJ×2moles)/1204kJ
=0.3887moles
one mole of MgO weighs 24+16=40
therefore the mass produced is 0.3887moles×40=15.548grams
(d) we first find the number of moles of MgO in 40.3 grams
number of moles=mass/RFM
=40.3g/40= 1.0075moles
if 2 moles of MgO give 1204 kJ then decomposing 1.0075 moles requires
(1.0075 moles×1204kJ)/2=606.515kJ
Flammable gases are gases that have the tendency to <u>explode (burst into flames)</u> when they come in contact with the <u>appropriate quantities of air, oxygen, or any suitable oxidant.</u>
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Devices that mix air or oxygen with flammable gasses cannot be used unless approved by an <u>authorized or approved personnel.</u>
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- Examples of flammable gases are hydrocarbons such as <u>Propane, Acetylene</u>, e.t.c.
- Flammable gases are dangerous to humans and the environment and if they are not handled properly, can cause severe damages and even death.
- During the preparation and usage of flammable gases, safety precautions should be properly enforced such as the <u>wearing of appropriate safety gear and goggles</u>.
- Devices that mix air or oxygen with flammable gases cannot be used unless approved by an <u>authorized or approved personnel.</u>
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The <u>Mole</u> is the SI unit that expresses the amount of substance.
Mole is defined as - The mole is the amount of substance containing the same number of entities as there are in the 12 grams of Carbon - 12.
Mole is denoted by using symbol mol.
Mole = 6.022 x 10²³ elementary entities.
These number of elementary entities in 1 mole is equal to or called as an Avogadro's number. Mole is equal to 6.022 x 10²³ because this number of entity is same as in exactly 12 g of carbon-12.
It is a very important SI unit of measured which is used by the chemists. Moles are used in measuring in small or tiny things such as atoms, molecules and the other tiny particles.
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Rocks, rocks can be used for many things depending on which rock you are talking about some rocks are used for construction of cement mixtures. Granite and marble are used for counter tops and desks depending on what district you go to school in and how funded the schools are there. pumice is a rock found in waters around volcanoes and is used to smooth organic surfaces such as feet. miscellaneous rocks are also used to prevent erosion. non living things can also include carbon which is the bases of life itself. Carbon is an organic element which is used in the synthesis medicines such as aspirin and poisons such as dichloromethane which is not used to poison others but is toxic to humans, it is mainly used for different isolation of unknown substances. Depending on what R grouping is attached to the carbon can be the deciding factor of how it can be used and how it can react with the environment. Elements like helium can be used in gas chromatograms and put into balloons
