The number of hydrogen ions would equal the number of hydroxide ions in a solution with a pH of what?

Engineers and constructions workers have different types of footwear, which they make use of when they are in the field. Each of these foot wears has its own purpose and functions. For instance, the steel toe boots serve to protect the foot from falling falling objects and also from compression. The foot wear has a protective support in the toe and also possesses a mid sole plate to protect the foot again puncture from the sole.

4 0

3 years ago

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To aid in the prevention of tooth decay, it is recommended that drinking water contains 0.900 ppm fluoride (F-). A) How many g o

Romashka-Z-Leto [24]

Answer:

a) <u>1.740 g</u> of F- must be added to a cylindrical water reservoir

b) Grams of sodium fluoride, NaF, that contain this much fluoride:

3.84 g

Explanation:

Step 1. calculate the volume of the tank:

Volume of cylinder =

$\pi r^{2}h$ ,

Here r = radius of the cylinder = d/2

h = depth = 21.80m

$r=\frac{d}{2}$

$=\frac{3.36x10^{2}}{2}$

= 168 m

Volume =

$=\frac{22\times 168^{2}\times 21.80}{7}$

$=1.93\times 10^{6} m^{3}$

2.Convert ppm to g/m3 and Solve for mass of F-

$1ppm = 1g/m^{3}$

$0.9ppm = 0.9g/m^{3}$

Because both ppm and g/m3 are same quantity .

$g/m^{3} =\frac{mass\ of\ F-(g)}{Volume\ m^{3}}\times 10^{6}$

$0.9 =\frac{mass\ of\ F-}{1.93\times 10^{6} m^{3}}\times 10^{6}$

$mass\ of\ F- =1.740g$

mass of F- required = 1.740 g

3. Apply <u>mole concept </u>to calculate grams of sodium fluoride produced

mass of 1 mole of F2 = 38 g

mass of 1 mole of NaF = 42 g

(from periodic table calculate molar mass)

$2Na+F_{2}\rightarrow 2NaF$

Here 1 mole of F2 produce = 2 mole of NaF

So,

38 g of F2 produce = 2 x 42 g of NaF

38 g of F2 produce = 84 g of NaF

1 g of F2 produce = 84/38 g of NaF

1.74 g F2 produce =

$\frac {84}{38}\times 1.74$

1.74 g F2 produce = 3.84 g of NaF

3.84 g of NaF is produced

3 0

3 years ago

Calcium carbonate is most likely to dissolve in water with which characteristics?

Marysya12 [62]

Calcium carbonate is most likely to dissolve in water with:

e. Lots of Carbon dioxide and colder temperature.

Explanation:

Calcium carbonate is very sparingly soluble in water. However, it has been observed to dissolve in cold water with higher concentration of Carbon dioxide.
The reason behind the observation is the formation of Calcium bicarbonate which is soluble in water.
Higher concentration of Carbon dioxide in water turns it acidic. When this acidic water reacts with calcium carbonate it forms Calcium bicarbonate which is soluble in water.
So,Calcium carbonate is most likely to dissolve in water with lots of Carbon dioxide and colder temperature.

4 0

3 years ago