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4 years ago

13

A class has a mixture of sand, iron filings, and water. Four different students shared ideas of how to separate the mixture. Whi

ch proposal would make separating the three parts of the mixture the fastest

1 answer:

suter [353]4 years ago

5 0

Answer: First separate the iron filings using a magnet, and then filter the sand out of the water.

Explanation: hope it helps

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Combustion of 9.511 grams of c4h10 will yield ____ grams of CO2

Flauer [41]

Answer:

$\boxed{28.81}$

Explanation:

We know we will need an equation with masses and molar masses, so let’s gather all the information in one place.

M_r: 58.12 44.01

2C₄H₁₀ + 13O₂ ⟶ 8CO₂ + 10H₂O

m/g: 9.511

1. Moles of C₄H₁₀

$\text{Moles of C$_{4}$H$_{10} $} = \text{ 9.511 g C$_{4}$H$_{10} $} \times \dfrac{\text{1 mol C$_{4}$H$_{10} $}}{\text{ 58.12 g C$_{4}$H$_{10} $}} = \text{0.1636 mol C$_{4}$H$_{10}$}$

2. Moles of CO₂

The molar ratio is 8 mol CO₂:2 mol C₄H₁₀

$\text{Moles of CO}_{2} =\text{0.1636 mol C$_{4}$H$_{10} $} \times \dfrac{\text{8 mol CO}_{2}}{\text{2 mol C$_{4}$H$_{10}$}} = \text{0.6546 mol CO}_{2}$

3. Mass of CO₂

$\text{Mass of CO}_{2} = \text{0.6546 mol CO}_{2} \times \dfrac{\text{44.01 g CO}_{2}}{\text{1 mol CO}_{2}} = \textbf{28.81 g CO}_{2}\\\\\text{The combustion will form $\boxed{\textbf{28.81 g CO}_{2}}$}$

8 0

3 years ago

Saltwater _____. has a pH of 10 is mostly used for irrigation and farming can be desalinized and used for drinking is mostly fou

tiny-mole [99]

I think the best statement to fill the blank is that "can be desalinized and used for drinking". The said statement seems the most appropriate one because the pH of saltwater is not 10 but approximately between 7.6 to 8.4. Also, saltwater is not found in glaciers, ice caps and aquifers instead it is freshwater.

8 0

4 years ago

Having difficulty understanding formulas involved. Determine the quantity (g) of pure CaCl2 in 7.5 g of CaCl2•9H2O.

Luda [366]

To determine the quantity of pure CaCl2 from the given amount of CaCl2.9H2O, we use the ratio of CaCl2 to CaCl2.9H2O. From the formula the ratio would 1 is to 1 We calculate as follows:

7.5 g CaCl2.9H2O (1 mol / 273.1215 g) ( 1 mol CaCl2 / 1 mol CaCl2.9H2O ) ( <span>110.98 g / 1 mol ) = 3.05 g CaCl2

Hope this answers the question. Have a nice day. Feel free to ask more questions.</span>

7 0

3 years ago

Serjik [45]

Answer:

D

Explanation:

Scientists measure a variety of properties to determine water quality. These include temperature, acidity (pH), dissolved solids (specific conductance), particulate matter (turbidity), dissolved oxygen, hardness and suspended sediment.

6 0

3 years ago

solution contains 174 grams of lithium bromide in 360 grams of water, what is the mole fraction of lithium bromide

Luba_88 [7]

Answer:

$\large\boxed{\large\boxed{0.091}}$

Explanation:

The<em> mole fraction</em> of a component in a mixture is the number of moles of the component divided by the total number of moles of all the components, multiplied by 100.

The symbol X is used to represent the mole fraction.

$X_A=\dfrac{\text{number of moles of component A}}{\text{number of moles of all the components}}\times 100$

<u />

<u>1. Convert masses in grams to number of moles</u>

Formula:

number of moles = mass in grams / molar mass

a) Lithium bromide

Chemical Formula: LiBr
Molar mass: 86.845 g/mol

$\text{Number of moles}=\dfrac{174g}{86.845g/mol}=2.00mol$

b) Water

Chemical formula: H₂O

Molar mass: 18.015 g/mol

$\text{Number of moles}=\dfrac{360g}{18.015g/mol}=19.98mol\approx 20.0mol$

c) Total number of moles = 2.00 mol + 20.0 mol = 22.0 mol

<u>2. Mole fraction of lithium bromide</u>

$\text{Mole fraction of lithium bromide}=\dfrac{2.00}{22.0}=0.091$

5 0

3 years ago