Ask question

Ask question

All categories

marshall27 [118]

1 year ago

7

A dentist is using an oral rinse that consists of a 9.76 x 10-2 mol/L sodium fluoride solution. Calculate the mass of sodium flu

oride required to prepare a 850 mL solution of this concentration

1 answer:

rjkz [21]1 year ago

8 0

Answer:

3.48 g NaF

Explanation:

Dimensional Analysis:

$\frac{(9.76*10^{-2})mol NaF}{1 L} * \frac{1L}{1000 mL} * \frac{41.99gNaF}{1 mol NaF} * 850 mL$

Answer (Simplifying the Expression Above):

3.48 g NaF

You might be interested in

Stacy made the following table to compare the functions of plant and animal structures, but she is missing a row title. Which of

fredd [130]

Answer:

female reproductive structures

6 0

2 years ago

A 40.0 L balloon is filled with air at sea level (1 atm @ 25 oC). It is then tied to a rock and thrown into a cold lake and it s

velikii [3]

To solve this question you need to calculate the number of the gas molecule. The calculation would be:
PV=nRT
n=PV/RT
n= 1 atm * 40 L/ (0.082 L atm mol-1K-<span>1 * 298.15K)
</span>n= 1.636 moles

The volume at bottom of the lake would be:
PV=nRT
V= nRT/P
V= (1.636 mol * 277.15K* 0.082 L atm mol-1K-1 )/ 11 atm= <span>3.38 L</span>

8 0

3 years ago

Determine the mole fractions and partial pressures of CO2, CH4, and He in a sample of gas that contains 1.20 moles of CO2, 1.79

BARSIC [14]

Answer : The mole fraction and partial pressure of $CH_4,CO_2$ and $He$ gases are, 0.267, 0.179, 0.554 and 1.54, 1.03 and 3.20 atm respectively.

Explanation : Given,

Moles of $CH_4$ = 1.79 mole

Moles of $CO_2$ = 1.20 mole

Moles of $He$ = 3.71 mole

Now we have to calculate the mole fraction of $CH_4,CO_2$ and $He$ gases.

$\text{Mole fraction of }CH_4=\frac{\text{Moles of }CH_4}{\text{Moles of }CH_4+\text{Moles of }CO_2+\text{Moles of }He}$

$\text{Mole fraction of }CH_4=\frac{1.79}{1.79+1.20+3.71}=0.267$

and,

$\text{Mole fraction of }CO_2=\frac{\text{Moles of }CO_2}{\text{Moles of }CH_4+\text{Moles of }CO_2+\text{Moles of }He}$

$\text{Mole fraction of }CO_2=\frac{1.20}{1.79+1.20+3.71}=0.179$

and,

$\text{Mole fraction of }He=\frac{\text{Moles of }He}{\text{Moles of }CH_4+\text{Moles of }CO_2+\text{Moles of }He}$

$\text{Mole fraction of }He=\frac{3.71}{1.79+1.20+3.71}=0.554$

Thus, the mole fraction of $CH_4,CO_2$ and $He$ gases are, 0.267, 0.179 and 0.554 respectively.

Now we have to calculate the partial pressure of $CH_4,CO_2$ and $He$ gases.

According to the Raoult's law,

$p_i=X_i\times p_T$

where,

$p_i$ = partial pressure of gas

$p_T$ = total pressure of gas = 5.78 atm

$X_i$ = mole fraction of gas

$p_{CH_4}=X_{CH_4}\times p_T$

$p_{CH_4}=0.267\times 5.78atm=1.54atm$

and,

$p_{CO_2}=X_{CO_2}\times p_T$

$p_{CO_2}=0.179\times 5.78atm=1.03atm$

and,

$p_{He}=X_{He}\times p_T$

$p_{He}=0.554\times 5.78atm=3.20atm$

Thus, the partial pressure of $CH_4,CO_2$ and $He$ gases are, 1.54, 1.03 and 3.20 atm respectively.

4 0

3 years ago

An 8 oz. bottle of energy drink contains 6.0 g of protein, 2.0 g of fat, and 16.3 g of carbohydrate. The fuel value of this ener

valina [46]

<u>Answer:</u> The correct option is d) 460 kJ

<u>Explanation:</u>

We are given:

Content of fat in energy drink = 2.0 g

Content of protein in energy drink = 6.0 g

Content of carbohydrate in energy drink = 16.3 g

Also,

The fuel value of fat = 38 kJ/g

The fuel value of protein = 17 kJ/g

The fuel value of carbohydrate = 17 kJ/g

So, the fuel value of the energy drink will be:

Total fuel value = $(2.0g\times 38 kJ/g)+(6.0g\times 17 kJ/g)+(16.3g\times 17 kJ/g)$

Total fuel value = $[76+102+277]=460kJ$

Hence, the correct option is d) 460 kJ

4 0

3 years ago

What is the atomic number of hydrogen??

Nataly_w [17]

The number is is surely 1

5 0

3 years ago