You will need a periodic table to help you answer this problem. The atomic numbers are arrange from lowest to highest in the periodic table. You can locate element number 55 to be Cesium with an atomic weight of 132.905 amu. So, you start from element 56. The following elements are:
56 Barium 137.328 amu
57 Lanthanium 138.905 amu
58 Cerium 140.116 amu
59 <span>Praseodymium 140.908 amu
60 Neodymium 144.243 amu
Neodymium is already greater than 144 amu. Therefore, these elements only include Barium, Lanthanium, Cerium and Praseodymium.</span>
B because once the circuit is burned the lights will all go of
Answer:
0.225 mol = 0.23 mol to 2 significant figures
Explanation:
Calculate the moles of oxygen needed to produce 0.090 mol of water
The equation of the reaction is given as;
2 C2H2 + 5 O2 --> 4 CO2 + 2 H2O
From the equation of the reaction;
5 mol of O2 produces 2 mol of H2O
x mol of O2 produces 0.090 mol of H2O
5 = 2
x = 0.090
x = 0.090 * 5 / 2
x = 0.225 mol
Almost all properties are common to elements within a single group on the periodic table. They react with water in the same way, they have the same number of valence electrons thereby having the same valency, the number of shells in the atom of the element increases by one as we move down the group.
In general, they have the same chemical properties as chemical properties depend on the number of electrons in the valence shell i.e. the outermost shell in the atom of an element.
<span>the process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a byproduct.
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