A student developed a chromatogram and found that the cluent front traveled 94 mm and the Zn²+ cation traveled

A graduated cylinder is filled with 60.0 ml of water. A cube, made of aluminum, is carefully dropped into the cylinder. Aluminum

katen-ka-za [31]

Answer:

65 ml

Explanation:

The aluminum will not float , so it will displace a volume of fluid equal to its volume.

13.5 gm / 2.7 gm/ml = 5 ml

the new graduated cylinder measurement will be 60 + 5 = 65 ml

3 0

2 years ago

Suppose that 98.0g of a non electrolyte is dissolved in 1.00kg of water. The freezing point of this solution is found to be -0.4

Sholpan [36]

Answer:

$\large \boxed{\text{392 u}}$

Explanation:

1. Calculate the molal concentration

The formula for the freezing point depression by a nonelectrolyte is

$\Delta T_{f} = -K_{f}b\\b = -\dfrac{\Delta T_{f}}{ K_{f}} = -\dfrac{-0.465 \, ^{\circ}\text{C}}{\text{1.86 $\, ^{\circ}$C$\cdot$kg$\cdot$mol}^{-1}} = \text{0.250 mol/kg}$

2. Calculate the moles of solute

$\begin{array}{rcl}b & = & \dfrac{\text{moles of solute}}{\text{kilograms of solvent}}\\\\\text{moles of solute} & = & b \times {\text{kilograms of solvent}}\\n & = &\text{0.250 mol/kg} \times \text{1.00 kg}\\ & = & \text{0.250 mol}\\\end{array}$

3. Calculate the molecular mass

$\begin{array}{rcl}\text{Moles} & = &\dfrac{\text{mass}}{\text{molar mass}}\\\\\text{0.250 mol} & = & \dfrac{\text{98.0 g}}{MM}\\\\MM & = & \dfrac{\text{98.0 g }}{\text{0.250 mol}}\\\\& = &\textbf{392 g/mol}\\\end{array}\\\text{The molecular mass of the solute is $\large \boxed{\textbf{392 u}}$}$

3 0

4 years ago

PLEASE NO FAKE ANSWERS!! Chemistry!!! Please will give brainliest !! Show work

Drupady [299]

When 1 mole of Zn and 2 mole of O₂ reacts togethor, It will produce 1 mole of ZnO as O₂ is excess reagent and Zn will act as Limiting reagent and thus it limits the amount of product formed.

<h3>What is Limiting reagent ?</h3>

Limiting reagents are the substances that are completely consumed first in a chemical reaction.

Given ;

Amopunt of Zn : 1 mole
Amount of O₂ : 2 mole

Given equation ;

2Zn + O₂ --> 2ZnO

As according to given chemical equation,

2 moles Zn of reacts with 1 mole of O₂ to produce 2 moles of ZnO.

Therefore,

1 mole of Zn will require 0.5 mole of O₂.

But,

the given amount of O₂ is 2 mole which is excess

Hence,

Zn here will act as the Limiting reagent, According to which the amount of product formed will be decided.

Therefore,

If 2 mole Zn produces : 2 moles of ZnO (According to given balanced equation)

Thus,

1 mole of Zn will produce = 2/2 x 1

= 1 mole of ZnO

Hence, When 1 mole of Zn and 2 mole of O₂ reacts togethor, It will produce 1 mole of ZnO as O₂ is excess reagent and Zn will act as Limiting reagent and thus it limits the amount of product formed.

Learn more about Limiting reagent here ;

brainly.com/question/11848702

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3 0

2 years ago

What is the significance of carbon having four valence electrons?

Dmitry_Shevchenko [17]

Answer:

Sorry for the late answer, but it should be A. Carbon's outermost shell can form up to 4 covalent bonds. It's one of the reasons why Carbon is considered an "essential element".

6 0

2 years ago

Consider the KF molecule, which has an ionic bond. The bond length is 2.17 x 1010 m (a) Calculate the energy required to dissoci

Natasha2012 [34]

Answer:

a) +640 kJ/mol or +1.06x10⁻¹⁸ J

b) +276 kJ/mol

Explanation:

To dissociate the molecule, the bond must be broken, thus, it's necessary energy equal to the energy of the bond, which can be calculated by:

E = (Q1*Q2)/(4*π*ε*r)

Where Q is the charge of the ions, ε is a constant (8.854x10⁻¹²C²J ⁻¹ m⁻¹), and r is the bond length. Each one of the ions has a charge equal to 1. The elementary charge is 1.602x10⁻¹⁹C, which will be the charge of them.

1 mol has 6.022x10²³ molecules (Avogadros' number), so the energy of 1 mol is the energy of 1 molecule multiplied by it:

E = 6.022x10²³ *(1.602x10⁻¹⁹)²/(4π*8.854x10⁻¹²*2.17x10⁻¹⁰)

E = +640113 J/mol

E = +640 kJ/mol

Or at 1 molecule: E =640/6.022x10²³ = +1.06x10⁻²¹ kJ = +1.06x10⁻¹⁸ J

b) The energy variation to dissociate the molecule at its neutral atoms is the energy of dissociation less the difference of the ionization energy of K and the electron affinity of F (EA):

498 = 640 - (418 - EA)

640 -418 + EA = 498

222 + EA = 498

EA = +276 kJ/mol

8 0

4 years ago