Given parameters;
Mass of gold colored metal beads = 425g
Volume of water displaced by beads = 48.0cm³
Unknown;
Identity of the metal = ?
Given densities;
Gold: 19.3 g/mL
Copper: 8.86 g/mL
Bronze: 9.87 g/mL
Density is an intensive property of any substance. This implies that we can use the density of any substance to identify it.
Density can be defined as the mass per unit volume of a substance. Every substance has a unique mass per volume.
Mathematically;
Density = 
where mass is in kg or g
volume is in m³ or cm³
To find the density, we must know the mass and volume.
In this problem, the volume of the gold metal beads is the same as the volume of water displaced. This is a way to measure volume of solids.
Since the volume is given in cm³, and we are comparing with choices that have units in g/mL, we simply convert the volume in cm³ to mL
1cm³ = 1mL³
So therefore, volume of gold colored metal is 48mL
Now input the parameters given and solve for the density;
Density =
= 8.85g/mL
From the given densities, we clearly see that copper is the metal since they both of similar densities.
Answer:
0.42 M
Explanation:
The reaction that takes place is:
- Cu(CH₃COO)₂ + Na₂CrO₄ → Cu(CrO₄) + 2Na(CH₃COO)
First we <u>calculate the moles of Na₂CrO₄</u>, using the <em>given volume and concentration</em>:
(200 mL = 0.200L)
- 0.70 M * 0.200 L = 0.14 moles Na₂CrO₄
Now we <u>calculate the moles of Cu(CH₃COO)₂</u>, using its <em>molar mass</em>:
- 40.8 g ÷ 181.63 g/mol = 0.224 mol Cu(CH₃COO)₂
Because the molar ratio of Cu(CH₃COO)₂ and Na₂CrO₄ is 1:1, we can directly <u>substract the reacting moles of Na₂CrO₄ from the added moles of Cu(CH₃COO)₂</u>:
- 0.224 mol - 0.14 mol = 0.085 mol
Finally we <u>calculate the resulting molarity</u> of Cu⁺², from the <em>excess </em>cations remaining:
- 0.085 mol / 0.200 L = 0.42 M
Answer: The mass of the sample will be 1417.7 grams.
Explanation:
We are given:

This means that 1 mole of NaCl has an enthalpy of fusion of 30.2 kJ
1 mole of NaCl has a mass of 58.44 grams.
So, 30.2 kJ of heat is require for a mass 58.44 grams of NaCl
So, 732.6 kJ of heat will be required for =
= 1417.65 grams of NaCl.
Hence, the mass of NaCl sample will be 1417.7 grams.