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3 years ago

What was discovered first helium or samarium?

1 answer:

7 0

The correct answer is helium, but both discoveries were quite close. Helium was discovered in 1868 during a solar eclipse by French astronomer Jules Janssen, while samarium was discovered in 1879 by a French chemist Paul Émile Lecoq de Boisbaudran.

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A new technology company is marketing drones for residential use. The bar graph shows the relation between number of sales and t

zhuklara [117]

Answer:

1- The graph provides a comparison of the different marketing strategies

2- The graph helps in selecting the best marketing strategy to improve sales

Explanation:

Hope this help

plz mark brainliest

Have a nice day!!!

4 0

4 years ago

Check my answer plz!! 100 points. Tell me if they are wrong! 1. You have three elements, A, B, and C, with the following electro

Artyom0805 [142]

look good w small changes below:

Answer:

AB is an ionic compound. The electronegativity difference between A and B is greater.

AC is an ionic compound. The electronegativity difference between A and C is greater.

BC is a covalent compound because the electronegativity difference between C and B is small.

everything else look good!

6 0

3 years ago

Read 2 more answers

write short notes on the following:1. Analytical chemist 2. Chemical engineer 3. Healthcare scientists 4. Forensic scientist 5.

worty [1.4K]

Analytical chemistry studies and uses instruments and methods used to separate, identify, and quantify matter. In practice, separation, identification or quantification may constitute the entire analysis or be combined with another method. Separation isolates analytes
Chemical engineers use chemistry and engineering to turn raw materials into usable products, such as medicine, petrochemicals, and plastics on a large-scale, industrial setting. They are also involved in waste management and research. ... They may be involved in designing and constructing plants as a project engineer.
A healthcare scientist or medical scientist is a scientist working in any of a number of health related disciplines. Healthcare scientists may work directly for health service providers, or in academia or industry.
Forensic science, also known as criminalistics, is the application of science to criminal and civil laws, mainly—on the criminal side—during criminal investigation, as governed by the legal standards of admissible evidence and criminal procedure.
Research scientists are responsible for designing, undertaking and analysing information from controlled laboratory-based investigations, experiments and trials. You could work for government laboratories, environmental organisations, specialist research organisations or universities.
Toxicology is a scientific discipline, overlapping with biology, chemistry, pharmacology, and medicine, that involves the study of the adverse effects of chemical substances on living organisms and the practice of diagnosing and treating exposures to toxins and toxicants.
A medicinal or pharmaceutical chemist researches and creates chemical compounds for use as drugs. By applying chemical research techniques to isolate natural healing agents or develop artificial ones, these chemists play a vital role in the pharmaceutical industry.
Nuclear chemists conduct basic, applied, or theoretical research. They often work in laboratories and may be responsible for operating, maintaining, and repairing state-of-the-art instrumentation.
Some industrial chemists work to improve product efficiency or to create better building materials, plastics, textiles, or petroleum products. They may help to set new industry standards, improve production techniques, and increase the effectiveness of various chemical processes.

7 0

3 years ago

Write and balance sodium when it burns in air to form sodium peroxide

Zanzabum

Answer:7.229 grams of oxygen is formed by the complete reaction of 35.23 g of metallic sodium with oxygen at 130–200 °C, a process that generates sodium oxide, which in a separate stage absorbs oxygen: 4 Na + O2 → 2 Na2O. The ozone oxidizes the sodium to form sodium peroxide.

7 0

3 years ago

URGENT!! This is timed, PLEASE HELP!

Andrews [41]

Answer:

99.24 gm of nitrogen .

Explanation:

molecular weight of ammonia = 17 , molecular weight of nitrogen = 28.

2 NH₃(g) + 3 CuO(s) → 1N₂(g) + 3 Cu(s) + 3 H₂O(g)

2 x 17 gm 28 gm

( 34 gm )

34 gm of ammonia forms 28 gms of nitrogen

1 gm of ammonia forms 28 / 34 gms of nitrogen

120.51 gn of ammonia forms 28 x 120.51 / 34 gms of nitrogen

28 x 120.51 / 34 gms

= 99.24 gms of nitrogen will be formed .

8 0

4 years ago