Assume an object A with a mass of 66.789 g and a volume of 10.1 mL. what is its density?

How many milliliters of 0.200 M NH4OH are needed to react with 12.0 mL of 0.550 M FeCl3?

trapecia [35]

Answer:

9.9 ml of 0.200M NH₄OH(aq)

Explanation:

3NH₄OH(Iaq) + FeCl₃(aq) => NH₄Cl(aq) + Fe(OH)₃(s)

?ml of 0.200M NH₄OH(aq) reacts completely with 12ml of 0.550M FeCl₃(aq)

1 x Molarity NH₄OH x Volume Am-OH Solution(L) = 2 x Molarity FeCl₃ x Volume FeCl₃ Solution

1(0.200M)(Vol Am-OH Soln) = 3(0.550M)(0.012L)

=> Vol Am-OH Soln = 3(0.550M)(0.012L)/1(0.200M) = 0.0099 Liter = 9.9 milliliters

5 0

3 years ago

What is the mass ratio and atomic ratio for cl2o7

elixir [45]

Answer:

Mass ratio: 71:112

Atomic ratio: 2:7

Explanation:

1. To get the mass ratio of of the compound Cl2O7, the following steps are followed:

- The atomic mass of Cl = 35.5g/mol, O = 16g/mol

- The mass of each element in the compound is as follows:

Cl2 = 35.5(2) = 71g

O7 = 16(7) = 112g

The mass ratio is the ratio of one mass of an element to another in the compound, hence, the mass ratio is 71:112

- The molar mass of the compound, Cl2O7, is determined:

71 + 112 = 183g/mol

- The mass percent of each element is determined by dividing the mass of each element present by the Molar Mass:

Cl = 71/183 = 0.3879 × 100 = 38.8%

O = 112/183 = 0.612 × 100 = 61.2%

2. Atomic ratio is the ratio of one atom in a molecule to another. It can be calculated this:

In Cl2O7, there are 9 total atoms (2 atoms of Cl + 7 atoms of oxygen).

Hence, that atomic ratio of Cl to oxygen in Cl2O7 is 2:7

6 0

2 years ago

If 36 000 kg of full cream milk containing 4% fat is to be separated in a 6 hour period into skim milk with 0.45% fat and cream

Yuri [45]

Answer:

B=5522.33kg/h

C=478.11kg/h

Explanation:

Hi! It's a mass balance. First we have to determine the inflow.

mass flow rate = 36000kg / 6h = 6000kg / h

We define the input variable

- input flow (A) = 6000kg / h

-XgA = percentage of fat in A = 0.04

We define output variables.

- skim milk (B)

-creme (C)

-XgB = fat percentage at B = 0.0045

-XgC = percentage of fat in C = 0.45

Then we can start with the balance.

As a general rule, the mass balance is:

Input = Output

Balance sheet

1) A = B + C

Fat balance

2) A * XgA = B * XgB + C * XgC

Now we can solve.

We replace and clear B in equation 2

6000kg / h * 0.04 = B * 0.0045 + C * 0.45

B = (240kg / h) /0.045-C*0.45/0.0045

3) B = 53333.33kg / h-C * 100

We replace equation 3 in 1 and clear C

A = B + C

6000kg / h = 53333.33kg / h-C * 100 + C

C=(6000kg/h-53333.33kg/h)/(-99)

C=478.11kg/h

We replace C in equation 3 and calculate B

B = 53333.33kg / h-478.11kg/h * 100

B=5522.33kg/h

Then we have the values of the outflows.

C=478.11kg/h

B=5522.33kg/h

7 0

3 years ago

A 118-ml flask is evacuated and found to have a mass of 97.129 g. when the flask is filled with 768 torr of helium gas at 35 ?c,

Inessa05 [86]

The full question asks to decide whether the gas was a specific gas. That part is missing in your question. You need to decide whether the gas in the flask is pure helium.

To decide it you can find the molar mass of the gas in the flask, using the ideal gas equation pV = nRT, and then compare with the molar mass of the He.

From pV = nRT you can find n, after that using the mass of gass in the flask you use MM = mass/moles.

1) From pV = nRT, n = pV / RT

Data:
V = 118 ml = 0.118 liter
R = 0.082 atm*liter/mol*K
p = 768 torr * 1 atm / 760 torr = 1.0105 atm
T = 35 + 273.15 = 308.15 K

n = 1.015 atm * 0.118 liter / [ 0.082 atm*liter/K*mol * 308.15K] =0.00472 mol

mass of gas = mass of the fask with the gas - mass of the flasl evacuated = 97.171 g - 97.129 g = 0.042

=> MM = mass/n = 0.042 / 0.00472 = 8.90 g/mol

Now from a periodic table or a table you get that the molar mass of He is 4g/mol

So the numbers say that this gas is not pure helium , because its molar mass is more than double of the molar mass of helium gas.

7 0

3 years ago

"what is the concentration of positive charge and mass in rutherford's atomic model called?"

Tamiku [17]

The concentration of positive charge and mass in Rutherford's atomic model is called the nucleus. Rutherford's experiments involving the use of alpha particle beams directed onto thin metal foils demonstrated the existence of the nucleus. The nucleus of an atom contains positively charge particles called protons and other uncharged particles called neutrons. According to this model most volume of an atom is made up of an empty space.

3 0

3 years ago