PLEASE HELP ME TAKE SOO LONG! (ima fail this test!) its a study guide!

High-pressure liquid chromatography (HPLC) is a method used in chemistry and biochemistry to purify chemical substances. The pre

kotykmax [81]

Answer:

3.41 x10⁶ torr

Explanation:

To solve this problem we need to remember the equivalency:

1 torr = 133.322 Pa

Then we can proceed to convert 4.55×10⁸ Pa into torr. To do that we just need to multiply that value by a fraction number, putting the unit that we want to convert from in the denominator, and the value we want to convert to in the numerator:

4.55x10⁸ Pa * $\frac{1torr}{133.322Pa} =$ 3.41 x10⁶ torr

6 0

4 years ago

A chemist adds of a M zinc nitrate solution to a reaction flask. Calculate the mass in grams of zinc nitrate the chemist has add

weqwewe [10]

corrected question: A chemist adds 135mL of a 0.21M zinc nitrate solution to a reaction flask. Calculate the mass in grams of zinc nitrate the chemist has added to the flask. Round your answer to significant digits.

Answer:

5.37g

Explanation:

0.21M means ; 0.21mol/dm³

1dm³=1L , so we can say 0.21mol/L

if 0.21mol of Zinc nitrate is contained in 1L of water

x will be contained in 135mL of water

x= 0.21*135*10³/1

=0.02835moles

number of moles= mass/ molar mass

mass= number of moles *molar mas

molar mass of Zn(NO₃)₂=189.36 g/mol

mass= 0.02835 *189.36

mass=5.37g

3 0

3 years ago

It takes 2 g of chlorine to sanitize 1,000,000g of water. How much chlorine will it take to sanitize a 40,000-gallon pool? ( 1 g

dimulka [17.4K]

Answer:

0.1g (Gallon) of chlorine

Explanation:

Formula

1 gallon = 3.7L; the density of water is 1.0g/ml

Given

2g (gallon) of chlorine to sanitize = 1,000,000g (gallon) of water

Solve

If 2g (gallon) chlorine = 1,000,000g (gallon)

∴, ? chlorine = 40,000

The First step; set up an equation

1000000/2 = 40000/?

The Next step; divide 1 million to 2

1000000 ÷ 2 = 500000

Then, divide the result by 40000

40000 ÷ 500000 = 0.08

In the nearest unit that is 0.1

Therefore, it will take 0.1g (gallon) of chlorine to sanitize a 40,000-gallon pool.

7 0

3 years ago

Read 2 more answers

A 3.00-kg block of copper at 23.0°C is dropped into a large vessel of liquid nitrogen at 77.3 K. How many kilograms of nitrogen

hammer [34]

Answer:

1.2584kg of nitrogen boils.

Explanation:

Consider the energy balance for the overall process. There are not heat or work fluxes to the system, so the total energy keeps the same.

For the explanation, the 1 and 2 subscripts will mean initial and final state, and C and N2 superscripts will mean copper and nitrogen respectively; also, liq and vap will mean liquid and vapor phase respectively.

The overall energy balance for the whole system is:

$U_1=U_2$

The state 1 is just composed by two phases, the solid copper and the liquid nitrogen, so: $U_1=U_1^C+U_1^{N_2}$

The state 2 is, by the other hand, composed by three phases, solid copper, liquid nitrogen and vapor nitrogen, so:

$U_2=U_2^C+U_{2,liq}^{N_2}+U_{2,vap}^{N_2}$

So, the overall energy balance is:

$U_1^C+U_1^{N_2}=U_2^C+U_{2,liq}^{N_2}+U_{2,vap}^{N_2}$

Reorganizing,

$U_1^C-U_2^C=U_{2,liq}^{N_2}+U_{2,vap}^{N_2}-U_1^{N_2}$

The left part of the equation can be written in terms of the copper Cp because for solids and liquids Cp≅Cv. The right part of the equation is written in terms of masses and specific internal energy:

$m_C*Cp*(T_1^C-T_2^C)=m_{2,liq}^{N_2}u_{2,liq}^{N_2}+m_{2,vap}^{N_2}u_{2,vap}^{N_2}-m_1^{N_2}u_1^{N_2}$

Take in mind that, for the mass balance for nitrogen, $m_1^{N_2}=m_{2,liq}^{N_2}+m_{2,vap}^{N_2}$ ,

So, let's replace $m_1^{N_2}$ in the energy balance:

$m_C*Cp*(T_1^C-T_2^C)=m_{2,liq}^{N_2}u_{2,liq}^{N_2}+m_{2,vap}^{N_2}u_{2,vap}^{N_2}-m_{2,liq}^{N_2}u_1^{N_2}-m_{2,vap}^{N_2}u_1^{N_2}$

So, as you can see, the term $m_{2,liq}^{N_2}u_{2,liq}^{N_2}$ disappear because $u_{2,liq}^{N_2}=u_{1,liq}^{N_2}$ (The specific energy in the liquid is the same because the temperature does not change).

$m_C*Cp*(T_1^C-T_2^C)=m_{2,vap}^{N_2}u_{2,vap}^{N_2}-m_{2,vap}^{N_2}u_1^{N_2}$

$m_C*Cp*(T_1^C-T_2^C)=m_{2,vap}^{N_2}(u_{2,vap}^{N_2}-u_1^{N_2})$

The difference $(u_{2,vap}^{N_2}-u_1^{N_2})$ is the latent heat of vaporization because is the specific energy difference between the vapor and the liquid phases, so:

$m_{2,vap}^{N_2}=\frac{m_C*Cp*(T_1^C-T_2^C)}{(u_{2,vap}^{N_2}-u_1^{N_2})}$

$m_{2,vap}^{N_2}=\frac{3kg*0.092\frac{cal}{gC} *(296.15K-77.3K)}{48.0\frac{cal}{g}}\\m_{2,vap}^{N_2}=1.2584kg$

3 0

4 years ago

Is it possible to make crystals by hand?

xeze [42]

Answer: Crystals are formed by the earth and the earth itself otherwise then its a fake crystal

Explanation:

Every crystal that exists was formed when earth was formed. Take diamonds for example, All diamonds were crushed for millions of years by the earth and that's why they are so valuable. All diamonds are just coal.

So your answer is no but fake crystals yes

8 0

2 years ago