To calculate the number of atoms of Cr, we first find the number of moles per unit of cubic centimeter of Cr. Then, use avogadros number for the number of atoms. Calculations are as follows:
1 cm^3 (7.15 g/cm^3) (1 mol / 51.996 g Cr) = 0.14 mol Cr
0.14 mol Cr ( 6.022 x 10^23 atoms Cr / 1 mol Cr ) = 8.28 x 10^22 atoms Cr
Answer:
Identify each equation as a composition reaction, a decomposition reaction, or neither.
Fe2O3 + 3 SO3 → Fe2(SO4)3
NaCl + AgNO3 → AgCl + NaNO3
(NH4)2Cr2O7 → Cr2O3 + 4 H2O + N2
Solution
In this equation, two substances combine to make a single substance. This is a composition reaction.
Two different substances react to make two new substances. This does not fit the definition of either a composition reaction or a decomposition reaction, so it is neither. In fact, you may recognize this as a double-replacement reaction.
A single substance reacts to make multiple substances. This is a decomposition reaction.
Test Yourself
Identify the equation as a composition reaction, a decomposition reaction, or neither.
C3H8 → C3H4 + 2 H2
Explanation:
I hope I help :)))
1 ounces ----------- 29.5735 mL
5 ounces ----------- ??
5 x 29.5735 / 1 => 147.868 mL
hope this helps!
Number of moles is found by formula n=mass/molar mass, or m/M. the molar mass is found by adding together the atomic masses of Na and Cl (22.99 + 35.45) to give 58.44 g/mol. Since the mass of NaCl is 75.0g, we find the number of moles as follows:
n = 75.0 / 58.44 = 1.28 mol
There are 8 oxygens if you multiply the 4 by the 2