In a) the final equation is AgNO3 + KCl = AgCl + KNO3, b) Ni(NO3)2 + Na2S = 2NaNO3 + NiS; c) CaCl2 + Na2CO3 = 2 NaCl + CaCO3. In 2) The total net equation is Ca 2+ + CO32- = CaCO3 (s).
Half-life refers to the time taken for half of the atoms in a radioactive substance to decay. Therefore in 1 half-life the 80 mg of substance will reduce to 40 mg. In another half-life it will reduce from 40 mg to 20 mg, then in a third half-life from 20 mg to 10 mg. Therefore the half-life is equal to the total time taken to decay from 80 mg to 10 mg divided by 3:
t(1/2) = 36 hours / 3 = 12 hours.
Answer:
109.7178g of H2O
Explanation:
First let us generate a balanced equation for the reaction. This is illustrated below:
2C3H8O + 9O2 —> 6CO2 + 8H2O
Next we will calculate the molar mass and masses of C3H8O and H20. This is illustrated below:
Molar Mass of C3H8O = (3x12.011) + (8x1.00794) + 15.9994 = 36.033 + 8.06352 + 15.9994 = 60.09592g/mol.
Mass of C3H8O from the balanced equation = 2 x 60.09592 = 120.19184g
Molar Mass of H2O = (2x1.00794) + 15.9994 = 2.01588 + 15.9994 = 18.01528g/mol
Mass of H2O from the balanced equation = 8 x 18.01528 = 144.12224g
From the equation,
120.19184g of C3H8O produced 144.12224g of H20.
Therefore, 91.5g of C3H8O will produce = (91.5 x 144.12224) /120.19184 = 109.7178g of H2O
Answer:
D, Li2S
Explanation:
This is because Lithium, which is in group IA of the periodic table, has a charge of +1. Sulfur will have a charge of -2 because it is in group 6A in the periodic table, which means to balance these out, there needs to be 2 lithium ions which would result in a charge of +2. With Lithium now having a charge of +2 due to having two atoms in the compound, and sulfur already having a charge of -2 as one atom, these two cancel out meaning the compound is neutral.
