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3 years ago

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25 POINTS + BRAINLIEST!!! How do you calculate the number of molecules in a substance? For example, Al2O3. (The numbers are subs

cripts) Please explain simply, to a point where a grade 9 can understand.

1 answer:

Scrat [10]3 years ago

3 0

You add them together

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2. Which electron dot structure represents a nonpolar molecule?

TEA [102]

Answer:

it's d. H:C:C:F

5 0

3 years ago

using the soubility curve what is the solubilityof nh4cl in 10 mL of water at a temperature of 60 degrees Celsius

lukranit [14]

Answer:

Please, see attached two figures:

The first figure shows the solutility curves for several soluts in water, which is needed to answer the question.

The second figure shows the reading of the solutiblity of NH₄Cl at a temperature of 60°C.

Answer: <u>5.5g</u>

Explanation:

The red arrow on the second attachement shows how you must go vertically from the temperature of 60ºC on the horizontal axis, up to intersecting curve for the <em>solubility</em> of <em>NH₄Cl.</em>

From there, you must move horizontally to the left (green arrow) to reach the vertical axis and read the solubility: the reading is about in the middle of the marks for 50 and 60 grams of solute per 100 grams of water: that is 55 grams of grams of solute per 100 grams of water.

Assuming density 1.0 g/mol for water, 10 mL of water is:

$10mL\times 1.0g/mL=10g$

Thus, the solutibily is:

$10gWater\times 55gNH_4Cl/100gWater=5.5gNH_4Cl$

5 0

3 years ago

List 3 categories of properties used to classify solids.

NNADVOKAT [17]

Answer : Broadly solids are divided into three categories;

i) Crystalline solids have a regular definite structure, in which the particles pack in a repeating pattern from one edge of the solid to the other.

ii) Amorphous solids have a random structure, with little unorganized pattern long-range order.

iii) Polycrystalline solids are those where an aggregate which consists of a large number of small crystals or grains in which the structure is regular, but the crystals or grains are found to be arranged in a random fashion.

Also solids can be divided into 3 more categories according to their bonds;

i) Covalent solids, like diamond, which forms crystals that can be viewed as a single giant molecule made up of an almost endless number of covalent bonds.

ii) Ionic solids are basically salts, such as NaCl, in which the molecules are held together by the strong force of attraction between ions of opposite charge.

iii) Metallic solids are found in metals which have the force of attraction between atoms of metals, such as copper and aluminum, or alloys, such as brass and bronze, are metallic bonds.

8 0

3 years ago

Read 2 more answers

Write the coefficients for the reactant and product.

balu736 [363]

<h3>Answer:</h3>

2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O

<h3>Explanation:</h3>

The equation for the reaction shown represents the combustion of ethane.

C₂H₆ + O₂ → CO₂ + H₂O

To balance the equation we put the coefficients, 2, 7, 4, and 6 on the reactants and products.

2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O

Balancing chemical equations makes the number of atoms of each element equal on both side of the equation.

It ensures that chemical equations obey the law of conservation of mass in chemical reactions.

4 0

3 years ago

Read 2 more answers

How many grams of phosphorus are in a sample of Ca3(PO4)2 that contains 50.0 g of calcium? Answer: ________ grams of phosphorus.

wel

<u>Answer:</u> The mass of phosphorus that is present for given amount of calcium is 28.53 g.

<u>Explanation:</u>

We are given:

Mass of calcium = 50 grams

The chemical formula of calcium phosphate is $Ca_3(PO_4)_2$

Molar mass of calcium = 40 g/mol

Molar mass of phosphorus = 31 g/mol

In 1 mole of calcium phosphate, 120 grams of calcium is combining with 62 grams of phosphorus.

So, 50 grams of calcium will combine with = $\frac{62}{120}\times 50=28.53g$ of phosphorus.

Hence, the mass of phosphorus that is present for given amount of calcium is 28.53 g.

6 0

3 years ago