Answer:
<u>glue that would make the strongest craft stick tower.</u>
Explanation:
<u>Independent variable: </u>In statistics and research methods, the term "independent variable" is determined as a variable that is being changed, controlled, or altered in an experiment or research by the researcher or the experimenter to see its effect on DV or dependent variable. However, it is said that independent variable directly effect the dependent variable.
Answer : The mass of sodium fluoride added should be 0.105 grams.
Explanation : Given,
The dissociation constant for HF = 
Concentration of HF (weak acid)= 0.0310 M
First we have to calculate the value of 
.
The expression used for the calculation of is,
Now put the value of 
in this expression, we get:
Now we have to calculate the concentration of NaF.
Using Henderson Hesselbach equation :
![pH=pK_a+\log \frac{[Salt]}{[Acid]}](https://tex.z-dn.net/?f=pH%3DpK_a%2B%5Clog%20%5Cfrac%7B%5BSalt%5D%7D%7B%5BAcid%5D%7D)
![pH=pK_a+\log \frac{[NaF]}{[HF]}](https://tex.z-dn.net/?f=pH%3DpK_a%2B%5Clog%20%5Cfrac%7B%5BNaF%5D%7D%7B%5BHF%5D%7D)
Now put all the given values in this expression, we get:
![2.60=3.17+\log (\frac{[NaF]}{0.0310})](https://tex.z-dn.net/?f=2.60%3D3.17%2B%5Clog%20%28%5Cfrac%7B%5BNaF%5D%7D%7B0.0310%7D%29)
![[NaF]=0.00834M](https://tex.z-dn.net/?f=%5BNaF%5D%3D0.00834M)
Now we have to calculate the moles of NaF.
Now we have to calculate the mass of NaF.
Therefore, the mass of sodium fluoride added should be 0.105 grams.
Answer:
3.25×10²⁴ molecules
Explanation:
From the question given above, the following data were obtained:
Mass of H₂O = 97.2 g
Number of molecule of H₂O =?
From Avogadro's hypothesis, we understood that:
1 mole of H₂O = 6.02×10²³ molecules
Next, we shall determine the mass of 1 mole of H₂O. This can be obtained as follow:
1 mole of H₂O = (2×1) + 16
= 2 + 16
= 18 g
Thus,
18 g of H₂O = 6.02×10²³ molecules
Finally, we shall determine the number of molecules in 97.2 g of H₂O. This can be obtained as follow:
18 g of H₂O = 6.02×10²³ molecules
Therefore,
97.2 g of H₂O = 97.2 × 6.02×10²³ / 18
97.2 g of H₂O = 3.25×10²⁴ molecules
Thus, 97.2 g of H₂O contains 3.25×10²⁴ molecules.
Answer:
my sagot kana bha pwede mo bha sagutan wala pa ako eh
Answer:
Nitrogen reacts with oxygen to form a number of nitrogen oxides. It exhibits different oxidation states in its oxides, ranging from +1 to +5. Oxides of nitrogen having nitrogen in the higher oxidation state are more acidic than that in lower oxidation state. Nitrogen oxides are critical components of photochemical smog. They produce the yellowish-brown colour of the smog. In poorly ventilated situations, indoor domestic appliances such as gas stoves and gas or wood heaters can be significant sources of nitrogen oxides.
Following are the harmful effects caused by the oxides of nitrogen
Nitrogen oxides causes irritation in mucous membrane.
Large concentrations of Nitrogen oxide causes lungs problems in humans
It causes injuries to vegetation by damaging leaves.
Nitrogen oxide oxidizes Hydrocarbons in the presence of sunlight, which causes eye irritation, asthama attacks, nasal and throat infections.
NO: sharp, sweet-smelling, colourless gas. Melting point: -163.6°C. Boiling point: -151.8°C. Relative Density: 1.04 (air = 1) NO2: reddish-brown gas with irritating odour
