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3 years ago

How much gold is harvested per ton of earth from the underground mine?

1 answer:

ozzi3 years ago

5 0

If you are referring to NOVA - Hunting the Elements documentary, then about one ounce per ton of earth from the underground mine. One haul equals to about 400 tons, which means there are about 25 pounds of gold per every truck, and one ounce costs $1,800.

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A 20.0 milliliter sample of 0.200 molar K₂CO₃ solution is added to 30.0 milliliters of 0.400 molar Ba(NO₃)₂ solution. Barium car

sveticcg [70]

Answer:

0.32M

Explanation:

Step 1: Balance the reaction

K2CO3 + Ba(NO3)2 ⇔ KNO3 + BaCO3

We have a 20 mL 0.2 M K2CO3 and a 30mL 0.4M Ba(NO3)2 solution

SinceK2CO3 is the limiting reactant, there will remain Ba(NO3)2 after it's consumed and produced KNO3 + BaCO3

Step 2: Calculate concentration

To find the concentration of the barium cation we use the following equation:

Concentration = moles of the solute / volumen of the solution

[Ba2+] = (20 * 10^-3 * 0.2M + 30 * 10^-3 * 0.4M) / ( 20 + 30mL) *10^-3

[Ba2+] = 0.32 M

The concentration of Barium ion in solution is 0.32 M

6 0

2 years ago

What is the mole fraction of NaOH in an aqueous solution that

astraxan [27]

Answer:

The mole fraction of NaOH in an aqueous solution that contain 22.9% NaOH by mass=0.882

Explanation:

We are given that

Aqueous solution that contains 22.9% NaOH by mass means

22.9 g NaOH in 100 g solution.

Mass of NaOH(WB)=22.9 g

Mass of water =100-22.9=77.1

Na=23

O=16

H=1.01

Molar mass of NaOH(MB)=23+16+1.01=40.01

Number of moles = $\frac{Given\;mass}{Molar\;mass}$

Using the formula

Number of moles of NaOH $(n_B)=\frac{W_B}{M_B}=\frac{22.9}{40.01}$

$n_B=0.572moles$

Molar mass of water=16+2(1.01)=18.02g

Number of moles of water $(n_A)=\frac{77.1}{18.02}$

$n_A=4.279 moles$

Now, mole fraction of NaOH

= $\frac{n_B}{n_B+n_A}$

$=\frac{4.279}{0.572+4.279}$

=0.882

Hence, the mole fraction of NaOH in an aqueous solution that contain 22.9% NaOH by mass=0.882

4 0

2 years ago

How manymoles of each ion are present in 175 mL of 0.147 M Fe2(SO4)3?

lilavasa [31]

Answer: 0.0257 moles of $Fe^{3+}$ and 0.0257 moles of $SO_4^{2-}$

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.

$Molarity=\frac{moles}{\text {Volume in L}}$

moles of $Fe_2(SO_4)_3=Molarity\times {\text {Volume in L}}=0.147\times 0.175L=0.0257moles$

The balanced reaction for dissociation will be:

$Fe_2(SO_4)_3\rightarrow Fe^{3+}+SO_4^{2-}$

According to stoichiometry:

1 mole of $Fe_2(SO_4)_3$ gives 1 mole of $Fe^{3+}$ and 1 mole of $SO_4^{2-}$

Thus there will be 0.0257 moles of $Fe^{3+}$ and 0.0257 moles of $SO_4^{2-}$

8 0

3 years ago

How many grams of nh3 can be produced from 3.72 mol of n2 and excess h2.

olganol [36]

N₂ + 3H₂ ⇒ 2NH₃
1mol : 2mol
3,72mol : 7,44mol

n = 7,44mol
M = 17g/mol

m = n * M = 7,44mol * 17g/mol = 126,48g

7 0

3 years ago

HELPPPPPPPPPPPPPPPPPPPPPPPP MEEHHHHHHHHHHHHHH

AnnZ [28]

Here you are looking on the Free Body diagram of a net force of 0N in both the x and y-directions. the only ones that has that condition met is A and C.

4 0

3 years ago