All categories

3 years ago

What is the purpose of the three R’s of resource management?

Chemistry

2 answers:

stepladder [879]3 years ago

7 0

In a much simpler answer... to // conserve resources // :)

Brrunno [24]3 years ago

3 0

<span>The Three R's: Reduce, Reuse and Recycle. The three R's - reduce, reuse and recycle - all help to cut down on the amount of waste we throw away. They conserve natural resources, landfill space and energy.

</span>

You might be interested in

What kind of rocks are formed by the precipitation of calcium carbonate (CaCO3) from sea water? Select all that apply.

Vikki [24]

Shale, and Sandstone are the rocks formed by precipitation of calcium carbonate from sea water.

Option B and D

<u>Explanation:</u>

Calcium carbonate can get precipitated from sea water and it forms rocks termed as limestones. These limestones are a variety of sedimentary rocks. Along with it, shale and sandstones are also varieties of sedimentary rocks and they also contain some of the precipitation of calcium carbonate.

The composition of sandstones consists of quartz and feldspar along with some of the composition of calcium carbonate. The same concept goes for Shale also. Basically, Shale is a mixuture of Clay but they can combine with limestone.

Thus, Shale, Sandstone and limestones are the rocks formed by precipitation of calcium carbonate from sea water.

6 0

3 years ago

Why has diamond has a high melting point

expeople1 [14]

Well since covalent bonds are strong and diamonds contains a lot of covalent bonds, it makes the diamond's melting point and boiling point very high.

6 0

2 years ago

Please help!!<br> I don’t understand

laiz [17]

<h3>Answer:</h3>

150 g Si

<h3>General Formulas and Concepts:</h3>

<u>Pre-Algebra</u>

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right<u> </u>

<u>Chemistry</u>

<u>Atomic Structure</u>

Reading a Periodic Table
Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.

<u>Stoichiometry</u>

Use Dimensional Analysis

<h3>Explanation:</h3>

<u>Step 1: Define</u>

[Given] 3.2 × 10²⁴ atoms Si

[Solve] grams Si

<u>Step 2: Identify Conversions</u>

Avogadro's Number

[PT] Molar Mass of Si - 28.09 g/mol

<u>Step 3: Convert</u>

[DA] Set up: $\displaystyle 3.2 \cdot 10^{24} \ atoms \ Si(\frac{1 \ mol \ Si}{6.022 \cdot 10^{23} \ atoms \ Si})(\frac{28.09 \ g \ Si}{1 \ mol \ Si})$
[DA] Multiply/Divide [Cancel out units]: $\displaystyle 149.266 \ g \ Si$

<u>Step 4: Check</u>

<em>Follow sig fig rules and round. Instructed to round to 2 sig figs.</em>

149.266 g Si ≈ 150 g Si

4 0

3 years ago

why can you find different features at an oceanic-continental convergent zone than those found at a continental-continental conv

arlik [135]

Continental plates are much thicker that Oceanic plates. At the convergent boundaries the continental plates are pushed upward and gain thickness. The rocks and geological layers are much older on continental plates than in the oceanic plates. The Continental plates are much less dense than the Oceanic plates.

7 0

2 years ago

Given the following data:

bagirrra123 [75]

$176.0 \; \text{kJ} \cdot \text{mol}^{-1}$

As long as the equation in question can be expressed as the sum of the three equations with known enthalpy change, its $\Delta H$ can be determined with the Hess's Law. The key is to find the appropriate coefficient for each of the given equations.

Let the three equations with $\Delta H$ given be denoted as (1), (2), (3), and the last equation (4). Let $a$ , $b$ , and $c$ be letters such that $a \times (1) + b \times (2) + c \times (3) = (4)$ . This relationship shall hold for all chemicals involved.

There are three unknowns; it would thus take at least three equations to find their values. Species present on both sides of the equation would cancel out. Thus, let coefficients on the reactant side be positive and those on the product side be negative, such that duplicates would cancel out arithmetically. For instance, $3 + (-1) = 2$ shall resemble the number of $\text{H}_2$ left on the product side when the second equation is directly added to the third. Similarly

$\text{NH}_4 \text{Cl} \; (s)$ : $-2 \; a = 1$
$\text{NH}_3\; (g)$ : $-2 \; b = -1$
$\text{HCl} \; (g)$ : $2 \; c = -1$

Thus

$a = -1/2\\b = 1/2\\c = -1/2$ and

$-\frac{1}{2} \times (1) + \frac{1}{2} \times (2) - \frac{1}{2} \times (3)= (4)$

Verify this conclusion against a fourth species involved- $\text{N}_2 \; (g)$ for instance. Nitrogen isn't present in the net equation. The sum of its coefficient shall, therefore, be zero.

$a + b = -1/2 + 1/2 = 0$

Apply the Hess's Law based on the coefficients to find the enthalpy change of the last equation.

$\Delta H _{(4)} = -\frac{1}{2} \; \Delta H _{(1)} + \frac{1}{2} \; \Delta H _{(2)} - \frac{1}{2} \; \Delta H _{(3)}\\\phantom{\Delta H _{(4)}} = -\frac{1}{2} \times (-628.9)+ \frac{1}{2} \times (-92.2) - \frac{1}{2} \times (184.7) \\\phantom{\Delta H _{(4)}} = 176.0 \; \text{kJ} \cdot \text{mol}^{-1}$

3 0

2 years ago