Calcium is in group IIA in the periodic table. A Ca ion has a charge of 2+. In order to solve this problem you can either see the periodic table or just look for the charge of the elemetns they give you.
K is group IA - charge of 2+
Magnesium IIA - charge 2+
Bromine VIIA charge of 1-
Scandium IB
The answer is B
1) The equation is already balanced;
Left side: 1C, 2H and 1O
Right side: 1C, 1O, 2H
2) Starting substances: water and carbon
There are two starting substances also called reactants. H2O which is a compound and C which is an element.
3) Ending substance asked for: H2.
This is hydrogen gas.
Stoichiometry:
1 mol of C produces 1 mol of H2
12.01 g of C productes 2.016 grams of H2
Ratio: 2.016 g of H2 / 12.01 g of C = X g of H2 / 34 g of C =>
x = 34 g of C* 2.016 g of H2 / 12.01 g of C= 5.707 g of H2
Producers (plants) use that energy to make food.
The energy from the sun provides heat on earth.
Answer:
a pure substance consists only of one element or one compound. a mixture consists of two or more different substances, not chemically joined together.
Explanation: