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vladimir1956 [14]
3 years ago
14

MULTIPLE CHOICE QUESTION

Chemistry
1 answer:
zubka84 [21]3 years ago
4 0

Answer:

This question will be answered based on general understanding of how a controlled experiment should be:

The answer is: We must make sure we are testing/changing only one variable, and controling others

Explanation:

A controlled experiment is an experiment in which the independent variable is changed for a particular group called the EXPERIMENTAL group and unchanged for another group called the CONTROL group.

In a controlled experiment, only one variable should be tested while the others should be kept constant in order to have an effective result or outcome. This is the case in this question, the type of music or soil should be unchanged for each plant because the experimenter must make sure that he/she is testing/changing only one variable, and controling others.

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How many moles are in 4177g of aluminum chloride
Luden [163]
The mole<span> is the </span>unit of measurement<span> in the </span>International System of Units<span> (SI) for </span>amount of substance<span>. It is defined as the </span>amount<span> of a </span>chemical substance<span> that contains as many representative particles, e.g., </span>atoms<span>, </span>molecules<span>, </span>ions<span>, </span>electrons<span>, or </span>photons<span>, as there are atoms in 12 </span>grams<span> of </span>carbon-12<span> (</span>12<span>C), the </span>isotope<span> of </span>carbon<span> with </span>relative atomic mass<span> 12 by definition. 
so to solve the moles, divide the mass with molar mass

moles = 4177 g / </span><span>133.34 g/mol
moles = 31.33 moles</span>
4 0
3 years ago
Draw the lewis structure for so42-. How many equivalent resonance structures can be drawn?
Elena-2011 [213]

Answer : The Lewis-dot structure and resonating structure of SO_4^{2-} is shown below.

Explanation :

Resonance structure : Resonance structure is an alternating method or way of drawing a Lewis-dot structure for a compound.

Resonance structure is defined as any of two or more possible structures of the compound. These structures have the identical geometry but have different arrangements of the paired electrons. Thus, we can say that the resonating structure are just the way of representing the same molecule.

First we have to determine the Lewis-dot structure of SO_4^{2-}.

Lewis-dot structure : It shows the bonding between the atoms of a molecule and it also shows the unpaired electrons present in the molecule.

In the Lewis-dot structure the valance electrons are shown by 'dot'.

The given molecule is, SO_4^{2-}

As we know that sulfur and oxygen has '6' valence electrons.

Therefore, the total number of valence electrons in SO_4^{2-} = 6 + 4(6) + 2 = 32

According to Lewis-dot structure, there are 12 number of bonding electrons and 20 number of non-bonding electrons.

Hence, the Lewis-dot structure and resonating structure of SO_4^{2-} is shown below.

8 0
3 years ago
Consider an ice cube and a hot radiator. Which has the higher thermal energy?
Law Incorporation [45]
The answer to your question is the radiator
8 0
2 years ago
How does classifying the components of air help us to solve the air quality crisis
Lubov Fominskaja [6]

Air pollution is

1. Coal

Herder and Sheep in Central Java. © Kemal Jufri / Greenpeace

A shepherdess watches over her flock of sheep that graze near a coal power plant in Jepara, Central Java, Indonesia. © Kemal Jufri / Greenpeace

Burning all fossil fuels is bad, but coal is the worst. When burnt, it releases more carbon dioxide (CO2) per unit of energy than oil or gas – which means it heats up our planet faster.

Coal is toxic too. Burning it releases elements like mercury and arsenic, and small particles of soot which contribute to air pollution. When we breathe it in, that soot harms our heart and lungs and even increases our risk of strokes.

But the worst thing about coal is how widespread it is. Coal provides more than a third of the world’s electricity. That’s more than any other single source! These power plants affect air quality for hundreds of kilometres – and are often placed right in the heart of cities – so countless millions of people get little respite from the pollution these plants cause.

We desperately need to wean ourselves off coal, and get our power from clean sources like wind, sun and tides.

Some counties have started. In 2019, coal power had its biggest slump ever recorded! But we need every country in the world to move much faster towards renewable energy. Greenpeace International has even mapped out how they could go about

Air pollution is indeed a crisis, but it’s a crisis we can solve – and around the world, people are solving it! Here’s what that looks like.

1. Coal

Coal is toxic too. Burning it releases elements like mercury and arsenic, and small particles of soot which contribute to air pollution. When we breathe it in, that soot harms our heart and lungs and even increases our risk of strokes.

But the worst thing about coal is how widespread it is. Coal provides more than a third of the world’s electricity. That’s more than any other single source! These power plants affect air quality for hundreds of kilometres – and are often placed right in the heart of cities – so countless millions of people get little respite from the pollution these plants cause.

We desperately need to wean ourselves off coal, and get our power from clean sources like wind, sun and tides

2. Cars

Most cars run on oil – petrol and diesel. And just like burning coal, burning oil comes with a huge environmental price tag. Petrol and diesel cars emit CO2 and other gases which heat our planet. On top of other nasties, the exhaust fumes these cars produce contain Nitrogen Dioxide (NO2), which is another pollutant that harms our health.

Cities around the world are waking up to the joys of car-free travel. From pedestrian zones, to proper public infrastructure to comprehensive and affordable public transport, there are so many ways cities can help us go car-free more often. And the benefits are many – from more space and cleaner air to a more active and healthy population.

But for those journeys that still need cars, we should start thinking about cars very differently. Rather than petrol and diesel, we should power cars with electricity.

3. Air pollution is no match for all of us, working together. All the solutions listed here are already happening around the world because people came together and demanded it.

Concerns about air pollution made Shenzhen, China electrify their bus fleet. Parents in Belgium mobilised because the air in schools was so dirty. Now, Brussels, its capital city, is banning petrol and diesel cars from 2030 and investing in public transport and cycling infrastructure. And around the world, concerns about the climate impacts of coal are causing governments to look into new ways of getting their power- Turkey has closed five coal power plants in 2020 alone!

4 0
3 years ago
Individual differences in a group is called what
noname [10]
I’m pretty sure it’s b
6 0
3 years ago
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