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3 years ago

G8_SCIENCE_BSA_21_22

Chemistry

1 answer:

S_A_V [24]3 years ago

8 0

Answer:

Explanation: Over the course of a year, areas near Earth’s equator receive more direct energy from the Sun than areas near Earth’s poles. Which of the following correctly describes one result of this heating pattern?

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You find a compound composed only of element X and chlorine and you know that the compound is 13.10% X by mass. Each molecule of

8_murik_8 [283]

Answer:

Explanation:

So, the formula for the compound should be:

$XCl_{6}$

Now we assume that we have 1 mol of substance, so we can make calculations to know the molar mass of element X, as follows:

$M_{Cl}=35.45g/mol\\$

So we have that 6 moles weight 212.7g, and we can make a rule of three to know the weight of compound X:

$212.7g\rightarrow 86.9\%\\x\rightarrow 13.1\%\\\\x=\frac{212.7g*13.1}{86.9} =32.06g$

As we used 1 mol, we know that the molar mass is 32.06g/mol

So the element has a molar mass of 32.06 g/mol and an oxidation state of +6, with this information, we can assure that the element X is sulfur, so the compound is $SCl_{6}$

8 0

3 years ago

If an automobile air bag has a volume of 11.5 l , what mass of nan3 (in

True [87]

Moles of NaN3 at STP = volume of gas / 22.4 = 11.5/22.4 = 0.5mole. Massof NaN3 = moles of NaN3 x molecular weight = 0.5 x 65 = 32.5 grams.

8 0

3 years ago

Read 2 more answers

Which of the following pieces of laboratory glassware should be used to most accurately measure out a 25.00 ml sample of a solut

wel

Answer:

The correct answer is 25 mL graduated cylinder (it should be used in all the cases)

Explanation:

In order to measure 25.00 ml sample of a solution it should be used a 25 mL graduated cylinder, as it is previously and properly calibrated. The other laboratory glassware, beaker and erlenmeyer, have graduations which are approximate, so they are used when exact volumes are not needed.

ii) graduated cylinder has the least uncertainly. It is more accurate than a beaker or erlenmeyer (to within 1%)

iii) A 25 mL graduated cylinder should be used because it is the most accurate lab glassware (between those were mentioned: beaker, erlenmeyer).

6 0

3 years ago

The atomic mass of Cu is 63.5. Find its electrochemical equivalent

FrozenT [24]

Answer:

The electrochemical equivalent of copper, Cu, is 3.29015544 × 10⁻⁷ g/C

Explanation:

The given parameters are;

The element for which the electrochemical equivalent is sought = Copper

The atomic mass of copper = 63.5

The electrochemical equivalent, 'Z', of an element or a substance is the mass, 'm', of the element or substance deposited by one coulomb of electricity, which is equivalent to a 1 ampere current flowing for a period of 1 second

Mathematically, we have;

m = Z·I·t = Z·Q

We have;

Cu²⁺ (aq) + 2·e⁻ → Cu

Therefore, one mole of Cu, is deposited by 2 moles of electrons

The charge carried one mole of electrons = 1 Faraday = 96500 C

∴ The charge carried two moles of electrons, Q = 2 × 96500 C = 193,000 C

Given that the mass of an atom of Cu = 63.5 a.m.u., the mass of one mole of Cu, m = 63.5 g

$Z = \dfrac{m}{Q} = \dfrac{63.5 \ g}{193,000 \ C} = 3.29015544 \times 10^{-4} \, g \cdot C^{-1}$

∴ Z = 3.29015544 × 10⁻⁴ g/C = 3.29015544 × 10⁻⁷ g/C

The electrochemical equivalent of copper, Cu, is Z = 3.29015544 × 10⁻⁷ g/C

7 0

3 years ago

Help ASAP please!!!!!!!!!!!

iris [78.8K]

Answer:

The second one

Explanation:

Gas pressure is caused by gas molecules bouncing off the container walls and each other. Every time a molecule changes direction because it hits a wall, the change in momentum results in a small push. Due to the large number of molecules involved, the pushes add up to a large amount of pressure.

7 0

3 years ago