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3 years ago

Pls help really easy just search the questions f u need to

Chemistry

2 answers:

noname [10]3 years ago

8 0

1. because it’s features are very very like the planet mars so is useful for research on the planet. 2. it protects scientists from the extreme temperatures. 3.i’m not sure but i guess they would research how suitable mars is for humans to live on?

kherson [118]3 years ago

5 0

Answer:i cant seee

Explanation:

none

You might be interested in

what’s the empirical and molecular formula for a compound with 20.2% sodium, 37.6% sulfur, 42.2%oxygen and a molar mass of 682.8

boyakko [2]

Answer:

Empirical formula: Na3S4O9

Molecular formula: Na6S8O18

Explanation:

1) To find the empirical formula, which is the simplest whole number ratio of each element that makes up this unknown compound, we first divide the portion of each element by it's respective atomic mass.

Na= 23g/mol, S= 32g/mol, O=16g/mol

Na = 20.2/23 = 0.878mol

S = 37.6/32 = 1.175mol

O = 42.2/16 = 2.638mol

Next, we divide each number of moles by the smallest value (0.878mol)

Na = 0.878/0.878 = 1

S = 1.175/0.878 = 1.34

O = 2.638/0.878 = 3.004

Next, we multiply each decimal fraction by 3 to make it whole no:

Na = 3

S= 4.02 ~ 4

O= 9.012 ~ 9

The simplest ratio between Na, S and O is 3:4:9 hence, the empirical formula is Na3S4O9

2) To get the molecular formula, we use the molecular weight of each element in the empirical ratio, and the overall molar mass of the compound i.e.

Molar mass of compound= 682.8g/mol

molecular weight of Na3S9O4 = (3 x 23g/mol) + (4 x 32 g/mol) + (9 x 16 g/mol)

= 69 + 128 + 144

= 341 g/mol

Hence, (Na3S4O9)n = 682.8g/mol

= (341)n = 682.8

n = 682.8/341

n = 2.002

n~ 2

Hence, molecular formula = (Na3S4O9)2

= Na6S8O18

8 0

4 years ago

Draw the products formed when cholesterol is treated with [1] bh3·thf; [2] h2o2, −oh. indicate the stereochemistry around any st

Andreas93 [3]

Alkene on Hydration yield Alcohols. When Asymmetric Alkenes are treated with water in the presence of acid they follow Markovnikoff rule, and the Hydrogen of incoming reagent goes to that carbon which contain more number of Hydrogen atoms. The reverse (Anti-Markovnikoff) is done by carrying out Hydroboration reaction.In this case the Hydrogen atom of incoming reagent goes to that carbon which contains less number of Hydrogen atoms. In this reaction both -H and -OH adds in syn fashion. The Hydroboration reaction of Chloestrol is shown below,

3 0

3 years ago

Using the relation dS = (δQ/T)int rev for the definition of entropy, calculate the change in the specific entropy of R-134a as i

pashok25 [27]

Answer:

The value of specific entropy = 0.847 $\frac{KJ}{kg K}$

Explanation:

Constant pressure = 120 K pa

From the property tables of R - 134 a at P = 120 K pa

Temperature T = - 22.5 ° c

Value of heat transfer = 212.32 $\frac{KJ}{kg}$

Thus entropy change ΔS = $\frac{dq}{T}$

⇒ ΔS = $\frac{212.32}{250.5}$

⇒ ΔS = 0.847 $\frac{KJ}{kg K}$

Therefore the value of specific entropy = 0.847 $\frac{KJ}{kg K}$

7 0

3 years ago

The decay of radioactive elements occurs at a fixed rate. The half-life of a radioisotope is the time required for one half of t

Stolb23 [73]

Answer:

100 grams of C-14 decays to 25 grams in 11,460 years.

The C-14 isotope is only useful for dating fossils up to about 50,000 years old

If an ancient bone contains 6.25% of its original carbon, then the bone must be 22,920 years old.

Explanation:

We already know that the half life of C-14 is 5,730 years. After the first half life, we have 50 grams remaining. This takes 5,730 years. After the second half life (11,460 years now gone) we have 25 grams of C-14 left.

If a fossil material is older than 50,000 years an undetectable amount of 14C is left in the sample hence Carbon-14 is no longer suitable for dating the sample.

From;

0.693/5730 = 2.303/t log (No/0.0625No)

Where;

t = time taken and No = initial amount of C-14

0.693/5730= 2.77/t

t = 22,920 years

6 0

3 years ago

If 5.48 g of CuNO3 is dissolved in water to make a 0.840 M solution, what is the volume of the solution in milliliters?

Ainat [17]

Answer:

34.8 mL

Explanation:

First we convert 5.48 g of CuNO₃ into moles, using its molar mass:

5.48 g CuNO₃ ÷ 187.56 g/mol = 0.0292 mol

Now we can calculate the volume of the solution, using the definition of molarity:

Molarity = moles / liters

0.840 M = 0.0292 mol / liters

liters = 0.0348 L

Finally we convert L into mL:

0.0348 L * 1000 = 34.8 mL

5 0

3 years ago