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andreyandreev [35.5K]

2 years ago

11

4. The picture shows a full moon.

2 answers:

Anuta_ua [19.1K]2 years ago

6 0

Answer:

A full moon occurs when the Moon appears as a complete circle in the sky.

Explanation:

- We see it as a full orb because the whole of the side of the Moon facing the Earth is lit up by the Sun's rays.

- The moon shows no visible light of its own, so we only see the parts of the moon that are lit up by other objects.

sineoko [7]2 years ago

3 0

The answer is d i hope this helps

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How does acid rain happen? (Use the term Sulfur Dioxide) PLS HALP

mafiozo [28]

Acid rain<span> is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. These substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as </span>acid rain<span>.</span>

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3 years ago

4 Which pair of ions is isoelectronic?

Softa [21]

Answer:

B. Na+ and O2-

Explanation:

Na+ plus has 10 electrons and O2- also has 10 electrons

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2 years ago

The column just before the stable noble gases are called the

Sergio039 [100]

Is called the Halogen

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2 years ago

Magnesium metal burns in air to form a mixture of magnesium oxide (MgO, M = 40.31) and magnesium nitride (Mg3N2, M = 100.95). A

dedylja [7]

Answer:

26.95 %

Explanation:

Air contains the highest percentage of oxygen and nitrogen gases. Magnesium then combines with both of the gases:

$2 Mg (s) + O_2 (g)\rightarrow 2 MgO (s)$

$3 Mg (s) + N_2 (g)\rightarrow Mg_3N_2 (s)$

Firstly, find the total number of moles of magnesium metal:

$n_{Mg} = \frac{1.000 g}{24.305 g/mol} = 0.041144 mol$

Let's say that x mol react in the first reaction and y mol react in the second reaction. This means:

$x + y = 0.041144 mol$

According to stoichiometry, we form:

$n_{MgO} = x mol, n_{Mg_3N_2} = \frac{y}{3} mol$

Multiplying moles by the molar mass of each substance will yield mass. This means we form a total of:

$m_{MgO} = 40.31x g, m_{Mg_3N_2} = \frac{y}{3} 100.95 g =$

The total mass is given, so we have our second equation to solve:

$40.31x + 33.65y = 1.584$

We have two unknowns and two equations, we may then solve:

$x + y = 0.041144$

$40.31x + 33.65y = 1.584$

Express y from the first equation:

$y = 0.041144 - x$

Substitute into the second equation:

$40.31x + 33.65(0.04144 - x) = 1.584$

$40.31x + 1.39446 - 33.65x = 1.584$

$6.66x = 0.18954$

$x = 0.028459$

$y = 0.041144 - x = 0.012685$

Moles of nitride formed:

$n_{Mg_3N_2} = \frac{y}{3} = 0.0042282 mol$

Convert this to mass:

$m_{Mg_3N_2} = 0.0042282 mol\cdot 100.95 g/mol = 0.4268 g$

Find the percentage:

$\omega_{Mg_3N_2} = \frac{0.4268 g}{1.584 g}\cdot 100\% = 26.95 \%$

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2 years ago

What group of plants was found in the mesozoic but not in the paleozoic?

const2013 [10]

Angiosperms didn't exist until the late Mesozoic era..

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3 years ago