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sammy [17]
3 years ago
10

Help assignment, please please

Chemistry
1 answer:
andrey2020 [161]3 years ago
7 0
True........................
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0.2640 g of sodium oxalate is dissolved in a flask and requires 30.74 mL of potassium
Free_Kalibri [48]

Moles of potassium permanganate = 0.0008

<h3>Further explanation  </h3>

Titration is a procedure for determining the concentration of a solution by reacting with another solution which is known to be concentrated (usually a standard solution). Determination of the endpoint/equivalence point of the reaction can use indicators according to the appropriate pH range  

Reaction

5Na2C2O4(aq) + 2KMnO4(aq) + 8H2SO4(aq) ---> 2MnSO4(aq) + K2SO4(aq) + 5Na2SO4(aq) +  10CO2(g) + 8H2O(1)

The end point ⇒titrant and analyte moles equal

titrant : potassium  permanganate-KMnO4

analyte : sodium oxalate - Na2C2O4

so moles of KMnO4 = moles of Na2C2O4

moles of Na2C2O4(mass = 0.2640 g, MW=134 g/mol) :

\tt mol=\dfrac{mass}{MW}\\\\mol=\dfrac{0.264}{134 g/mol}\\\\mol=0.002

From equation, mol ratio  Na2C2O4 : KMnO4 = 5 : 2, so mol KMnO4 :

\tt \dfrac{2}{5}\times 0.002=0.0008

6 0
3 years ago
How many atoms are in a sample of 68.7 g copper (Cu)?
dlinn [17]
<span>Divide the number of grams present in the sample by copper's gram atomic weight to find the number of gram atomic weights present. Then multiply that result by Avogadro's Number: 6.022137 x 10^23 atoms/gram atomic weight.1,200 g/(63.54 g/gram atomic weight) ? 18.885741 gram-atomic weights. Hope this helps. </span>
8 0
3 years ago
Read 2 more answers
Name the homologous series for this compound and show its structure<br>ch3ch2cc(ch2)2ch3​
kotykmax [81]

Answer:

Alkyne

Explanation:

The homologous series for this compound is the Alkyne because of the presence of the triple bond present between the third and fourth carbon atoms as seen in the picture attached.

5 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
An element that has 2 core electrons and 3 valence electrons
gavmur [86]

Answer:

Boron

Explanation:

You can find this by looking at the number of protons in Boron, 5.

Then calculate how many electrons you are given, in this case the 2 core plus the 3 valence equal 5 total electrons

Neutral elements have the same number of protons and electrons, so your answer would be the element with 5 electrons, Boron.

You can also know this by using electron configuration. Since you kow there are 5 electrons then you can use EC to find out where your element is. In this case it is: 1s2 2s2 2p1

6 0
3 years ago
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