Please answer these 1.Which of the following lists both an element and a mixture
ID: 1022596 • Letter: P
Question
Please answer these
1.Which of the following lists both an element and a mixture?
1.oxygen and ozone
2.carbon and water
3.tin and brass
4.liquid water and steam
2.Which one of the following observations would demonstrate that a substance is a compound?
1.It can be separated into simpler substances by physical methods.
2.It cannot be separated into simpler substances by physical methods, but it can be separated into simpler substances by chemical methods.
3.Heating the substance causes it to melt, and then to boil.
4.It cannot be separated into simpler substances by physical or chemical methods.
3.Which of the following compounds is incorrectly named?
K3PO4 is potassium phosphate
NH4NO3 is ammonium nitrate
Mg(OH)2 is magnesium dihydroxide
MgSO3 is magnesium sulfite
CaO is calcium oxide
4.The combustion of gasoline to propel a car is an example of
1.the conversion of electrical energy to chemical potential energy.
2.the conversion of chemical potential energy to mechanical energy.
3.the conversion of mechanical energy to thermal energy.
4.the conversion of thermal energy to electrical energy.
5.A sphere with a radius equal to 16.1 meters and a mass of 465 kilograms has what density?
A.7.57×106 g/cm3
B.26.6 g/cm3
C.2.66×10-5 g/cm3
D.3.76×104 g/cm3
E.7.57×1012 g/cm3
Explanation / Answer
Q1.
note that in order to have an element, it must be found in the periodic table. Options are oxygen, carbon and tin, ignore option d, since it is not element.
Then, we must have a mixture of the SAME element, so ignore b and c.
Oxygen and Ozone, that is, O and O3, is the nearest answer
Q2.
a compound is a substnace that is formed by at least 2 elements.
then:
1.It can be separated into simpler substances by physical methods. FALSE, it must be done bya chemical processes, since they are chemically bonded
2.It cannot be separated into simpler substances by physical methods, but it can be separated into simpler substances by chemical methods. TRUE, as stated before
3.Heating the substance causes it to melt, and then to boil. FALSE, since it is a physical process
4.It cannot be separated into simpler substances by physical or chemical methods. FALSE, as stated in 2, we can do this by chemical means.
Q3..Which of the following compounds is incorrectly named?
K3PO4 is potassium phosphate - It follows the rules, no need to state tripotassium
NH4NO3 is ammonium nitrate - It follows the rules
Mg(OH)2 is magnesium dihydroxide - This is wrong, since Mg cna only be +2 charged, it is obvious that this is 2 times OH- groups... it is simply magnesium hydroxide
MgSO3 is magnesium sulfite - Correct, since SO3 is sulfite, both are +2 and -2 charged, no need to state so
CaO is calcium oxide - Correct, no need to state mono or di
Q4.
Combustion of gaosline is CHEMICAL process. It changes chemical energy to use for movement. Movement is associated to mechanical energy, choose:
2.the conversion of chemical potential energy to mechanical energy.
5.
D = mass /V
m = 465 kg = 465000 g
V = of sphere = 4/3*PI*R^3
V = 4/3*(3.1416)(16.1^3) = 17481.039 m3 = 17481039000 cm3
D = 465000 / 17481039000
D = 0.00002660024 g/cm3
D = 2.660*10^-5 g/cm3
nearest answer is C