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3 years ago

Which has a higher melting point k2O or MgO??? Please hurry!!

Chemistry

1 answer:

ycow [4]3 years ago

4 0

Answer:

MgO (Magnesium Oxide)

Explanation:

K20 = 1,343° ±5° C

MgO = 5,166°F (2,852°C)

MgO > K20

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What is the mass of 61.9 L of oxygen gas collected at STP?

Tcecarenko [31]

Answer:

D. 44.2 g O₂

General Formulas and Concepts:
Gas Laws

STP (Standard Conditions for Temperature and Pressure) = 22.4 L per mole at 1 atm, 273 K

Stoichiometry

Dimensional Analysis
Mole Ratio

Explanation:

Step 1: Define

Identify given.

61.9 L O₂ at STP

Step 2: Convert

We know that the oxygen gas is at STP. Therefore, we can set up and solve for how many moles of O₂ is present:

$\displaystyle 61.9 \ \text{L} \ \text{O}_2 \bigg( \frac{1 \ \text{mol} \ \text{O}_2}{22.4 \ \text{L} \ \text{O}_2} \bigg) = 2.76339 \ \text{mol} \ \text{O}_2$

Recall the Periodic Table (Refer to attachments). Oxygen's atomic mass is roughly 16.00 grams per mole (g/mol). We can use a mole ratio to convert from moles to grams:

$\displaystyle 2.76339 \ \text{mol} \ \text{O}_2 \bigg( \frac{16.00 \ \text{g} \ \text{O}_2}{1 \ \text{mol} \ \text{O}_2} \bigg) = 44.2143 \ \text{g} \ \text{O}_2$

Now we deal with sig figs. From the original problem, we are given 3 significant figures. Round your answer to the exact same number of sig figs:

$\displaystyle 44.2143 \ \text{g} \ \text{O} \approx \boxed{ 44.2 \ \text{g} \ \text{O}_2 }$

∴ our answer is letter choice D.

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Topic: AP Chemistry

Unit: Stoichiometry

6 0

2 years ago

5. The statement that in undisturbed sedimentary rock layers,

Colt1911 [192]

Answer:

The correct answer is - option C. Law of superposition.

Explanation:

According to the law of superposition states that within a sequence of layers of natural sedimentary rock without any disturbance, the oldest layer is lies under the younger layers with ascending order in the sequence.

If a sedimentary rock has 4 layers as a, b, c and d where the younger layer d would be on top and the oldest layer a would be at the bottoms.

Thus, the correct answer is - option C.

7 0

3 years ago

Read 2 more answers

Figure 2 shows what happens to the electrons in the outer shells when a sodium atom reacts with a fluorine atom.

QveST [7]

Sodium reacts with fluorine to make a covalent bond between them. A covalent bond is formed when there is a mutual sharing of electrons between the two adjacent atoms.

Here, Sodium is metal and fluorine is non-metal. So, the bond between them may be an ionic bond, but as the Sodium has one valence electron and fluorine is highly electronegative. Sodium wants to lose electrons and fluorine wants to gain electrons to form a chemical bond. Therefore, the sodium donates its valence electron to fluorine, forms a cation, and fluorine accepts the electron and forms an anion and they distribute the difference in the charge between them.