The density of pure gold (au) is 19.3 g/cm3. what is the mass of a block of gold that measures 1.2 cm x 5.00 cm x 3.20 cm? please show work.
Given: Density of pure gold = 19.3 g /cm^3
Measurement of block of gold =1.2 cm x 5.00 cm x 3.20 cm
To calculate : mass of gold
Formula used: Density = Mass / Volume
Volume = 1.2 cm x 5.00 cm x 3.20 cm = 19.2 cm^3
Mass of gold = Density X volume = 19.3 g /cm^3 X 19.2 cm^3 = 370.56 g
Answer:
43.0 kJ
Explanation:
The free energy (ΔG) measures the total energy that is presented in a thermodynamic system that is available to produce useful work, especially at thermal machines. In a reaction, the value of the variation of it indicates if the process is spontaneous or nonspontaneous because the free energy intends to decrease, so, if ΔG < 0, the reaction is spontaneous.
The standard value is measured at 25°C, 298 K, and the value of free energy varies with the temperature. It can be calculated by the standard-free energy of formation (G°f), and will be:
ΔG = ∑n*G°f products - ∑n*G°f reactants, where n is the coefficient of the substance in the balanced reaction.
By the balanced reaction given:
2NOCl(g) --> 2NO(g) + Cl2(g)
At ALEKS Data tab:
G°f, NOCl(g) = 66.1 kJ/mol
G°f, NO(g) = 87.6 kJ/mol
G°f, Cl2(g) = 0 kJ/mol
ΔG = 2*87.6 - 2*66.1
ΔG = 43.0 kJ
Answer:
single replacement
Explanation:
Step 1: Data given
single replacement = A reaction in which one element replaces a similar element in a compound. For example, a metal replaces an other metal.
The general form of a single-replacement (also called single-displacement) reaction is:
A+BC→AC+B
Decomposition = a reaction in which a compound breaks down into two or more simpler substances. The general form of a decomposition reaction is:
AB→A+B
Synthesis = A reaction that occurs when one or more compounds combines to form a complex compound:
A + B → AB
Double replacement: a reaction in which the positive and negative ions of two ionic compounds exchange places to form two new compounds.
The general form of a double-replacement reaction is:
AB+CD→AD+BC
Combustion reaction = a reaction in which a substance reacts with oxygen gas, releasing energy in the form of light and heat. Combustion reactions must involve O2 as one reactant.
The reaction Zn + 2HCl → ZnCl2 + H2
⇒ Does not involve O2 = NOT a combustion reaction
⇒ The compounds do not form a complex compound = NOT a synthesis
⇒ A compound does not break down into smaller substances = NOT a decomposition
⇒ There is a replacement between Zn and H. This is a <u>single replacement</u>, not a double replacement reaction.
