All categories

3 years ago

The Bantu were experts in this form of metallurgy. gold steel iron copper

2 answers:

4 0

they're experts in iron metallurgy

The bantu was originated from the southern part of Africa ( round republic of Congo) , and has been the expert of utilizing iron among the ancient tribe

Mostly they use it for their Agricultural system ( such as their Irrigation system, for their agricultural tools, etc)
<span />

Karolina [17]3 years ago

4 0

Iron that the answer

You might be interested in

g Calculate the pH when (a) 24.9 mL and (b) 25.1 mL of 0.100 M HNO3 have been added to 25.0 mL of 0.100 M KOH solution.

jarptica [38.1K]

Answer:

Following are the responses to the given choices:

Explanation:

For point a:

Using the acid and base which are strong so,

moles of $H^+$ (from $HNO_3$ )

$= 24.9\ mL \times 0.100\ M \\\\= \frac{24.9}{1000\ L} \times 0.100\ M \\\\= 2.49 \times 10^{-3} \ mol$

moles of $OH^{-}$ (from $KOH$ )

$= 25.0\ mL \times 0.100\ M \\\\= \frac{25.0}{1000 \ L} \times 0.100 \ M \\\\\= 2.50 \times 10^{-3}\ mol$

$1\ mol H^{+} \ neutralizes\ 1\ mol\ of\ OH^{-}$

So, $(2.50 \times 10^{-3} mol - 2.49 \times 10^{-3} mol)$ i.e. $1 \times 10^{-5}$ mol of $OH^-$ in excess in total volume $(24.9+25.0) \ mL = 49.9 \ mL$ i.e. concentration of $OH^- = 2 \times 10^{-4}\ M$

$p[OH^{-}] = -\log [OH^{-}] = -\log [2 \times 10^{-4}\ mol] = 3.70$

Since, $pH + pOH = 14,$

so,

$\to pH = 14- pOH = 14- 3.70 = 10.30$

For point b:

moles of $OH^-$ = from point a $= 2.50 \times 10^{-3} \ mol$

moles of $H^+$ (from $HNO_3$ ):

$= 25.1 mL \times 0.100 M\\\\ = \frac{25.1}{1000}\ L \times 0.100 \ M\\\\ = 2.51\times 10^{-3} \ mol$

1 mol $H^+$ neutralizes 1 mol of $OH^-$

So, $(2.51 \times 10^{-3}\ mol - 2.50 \times 10^{-3}\ mol)$ i.e. $1 \times 10^{-5} \ mol \ of\ H^+$ in excess in the total volume of $(25.1+25.0) \ mL = 50.1\ mL$ i.e. concentration of $H^+ = 2 \times 10^{-4}\ M$

Hence, $pH = -\log [H^+] = -\log[2 \times 10^{-4}] = 3.70$

6 0

3 years ago

A student titrates a 20.00 mL sample of an aqueous borax solution with 1.03 M H2SO4. If 2.07 mL of acid are needed to reach the

RSB [31]

Answer:

The concentration of the borax solution is 0.1066 M

Explanation:

Step 1: Dtaa given

Volume of a sample of aqueous borax solution = 20.00 mL = 0.020 L

Molarity of H2SO4 = 1.03 M

Volume of the H2SO4 = 2.07 mL = 0.00207 L

Step 2: The balanced equation

Na2B4O7*10H2O(borax) + H2SO4 ⇆ Na2SO4 + 4 H3BO3 + 5 H2O

Step 3: Calculate molarity of borax solution

b*Ca*Va = a * Cb*Vb

⇒with B = the coefficient of H2SO4 = 1

⇒with Ca = the concentration of borax = TO BE DETERMINED

⇒with Va = the volume of borax = 0.020 L

⇒with a = the coefficient of borax = 1

⇒with Cb = the concentration of H2SO4 = 1.03 M

⇒with Vb = the volume of H2SO4 = 0.00207 L

Ca*0.020 L = 1.03 M * 0.00207 L

Ca = (1.03 * 0.00207) / 0.020

Ca = 0.1066 M

The concentration of the borax solution is 0.1066 M

6 0

4 years ago

A yellow element stinks when burned

Ivenika [448]

Sulfur smells like rotten egg and is yellow...

3 0

3 years ago

Which star reaches a greater apparent brightness?

BARSIC [14]

Answer:

he distance to a star can be found by comparing its luminosity to its apparent brightness.

Explanation: A star that is far away will be very dim compared to its luminosity. So it proves that the ratio of its luminosity to apparent brightness will be greater than for a nearby star.

5 0

3 years ago

Potassium cyanide is a toxic substance, and the median lethal dose depends on the mass of the person or animal that ingests it.

skelet666 [1.2K]

<span>(8.5 x 10^-3 mol) / (0.0320 mol/L KCN)=0.265625 L=265.625 ml. This is the volume of a 0.0320 M KCN solution that would give a median lethal dose to a 185 lb person.</span>

7 0

3 years ago