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3 years ago

Hạt nhân nguyên tử được tạo bởi

Chemistry

1 answer:

Anna007 [38]3 years ago

8 0

Answer:

The FitnessGram™ Pacer Test is a multistage aerobic capacity test that progressively gets more difficult as it continues. The 20 meter pacer test will begin in 30 seconds. Line up at the start. The running speed starts slowly, but gets faster each minute after you hear this signal. [beep] A single lap should be completed each time you hear this sound. [ding] Remember to run in a straight line, and run as long as possible. The second time you fail to complete a lap before the sound, your test is over.

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How many moles of hydrogen are in the sample? Round your answer to 4 significant digits.

finlep [7]

Answer:

1.56 mol H₂

Explanation:

Mg₃(Si₂O₅)₂(OH)₂

There are 4 Si moles per Mg₃(Si₂O₅)₂(OH)₂ mol. With that in mind we can calculate how many Mg₃(Si₂O₅)₂(OH)₂ moles are there in the sample, using the given number of silicon moles:

3.120 mol Si * $\frac{1molMg_3(Si_2O_5)_2(OH)_2}{4molSi}$ = 0.78 mol Mg₃(Si₂O₅)₂(OH)₂

Then we can convert Mg₃(Si₂O₅)₂(OH)₂ moles into hydrogen moles, keeping in mind that there are 2 hydrogen moles per Mg₃(Si₂O₅)₂(OH)₂ mol:

0.78 mol Mg₃(Si₂O₅)₂(OH)₂ * 2 = 1.56 mol H₂

8 0

2 years ago

Carbon dioxide (CO2) is the gas that is mainly responsible for global warming (the greenhouse effect). The burning of fossil fue

Nesterboy [21]

Answer:

$1.7\cdot 10^{15} g$

Explanation:

Glucose reacts with oxygen do produce carbon dioxide and water:

$C_6H_12O_6 (s) + 6 O_2 (g)\rightarrow 6 CO_2 (g) + 6 H_2O (l)$

Given a daily mass of glucose:

$m_1 = 5.0\cdot 10^2 g$

Find moles of glucose:

$n_1 = {5.0\cdot 10^2 g}{180.156 g/mol} = 2.775 mol$

From stoichiometry of this equation, moles of carbon dioxide can be found by multiplying this amount by 6:

$n_2 = 2.775 mol\cdot 6=16.65 mol$

Convert this into mass using the molar mass of carbon dioxide:

$m_2 = 16.65 mol\cdot 44.01 g/mol = 732.8 g$

This is the mass of carbon dioxide per person per day. Multiply by the population and by the number of days to get the total mass:

$732.8 \frac{g}{person\cdot day}\cdot 365 days\cdot 6.5\cdot 10^9 people = 1.7\cdot 10^{15} g$

5 0

2 years ago

On average, how many hours of sleep do teenagers need each night? 7 hours 7.5 hours 8 hours 8.5 hours

Marrrta [24]

Answer:

8 to 8.5 since that is the recommended and people usualy sleep more than that

5 0

2 years ago

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Imagine a substance that is a red, shiny solid at room temperature, with a melting point of 115 °C. It is brittle and a poor con

AlexFokin [52]

Explanation:

Metals and non-metals can be identified either by their position in the periodic table or by their properties.

he metal elements are found on the left hand side of the periodic table, and the non-metal elements are found on the right. You can imagine a zig-zag line, starting at B-Al-Si, separating metals from non-metals.

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3 years ago

What inner planet has enough gravity to hold on to all its gases

Viefleur [7K]

The earth has enough gravity to do that

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3 years ago

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