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4 years ago

BRAINLIESTTT ASAP!!! PLEASE HELP ME :)

Chemistry

1 answer:

Iteru [2.4K]4 years ago

5 0

<h3>✽ - - - - - - - - - - - - - - - ~Hello There!~ - - - - - - - - - - - - - - - ✽</h3>

➷ Astrology: It hasn't shown any clear effectiveness in studies and doesn't have any scientific validity.

Aromatherapy with essential oils: It is only backed with low quality studies that just demonstrate the placebo effect

Acupuncture: Lots of research suggests it is just the placebo effect so it has no scientific backing

➶ Hope This Helps You!

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↬ <u>ʜᴀɴɴᴀʜ</u> ♡

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Will mark brainliest!

aniked [119]

The decoders of the DNA messege

4 0

4 years ago

PLZ HELP *NO LINKS*

Radda [10]

Answer: (1). There are 0.0165 moles of gaseous arsine (AsH3) occupy 0.372 L at STP.

(2). The density of gaseous arsine is 3.45 g/L.

Explanation:

1). At STP the pressure is 1 atm and temperature is 273.15 K. So, using the ideal gas equation number of moles are calculated as follows.

PV = nRT

where,

P = pressure

V = volume

n = number of moles

R = gas constant = 0.0821 L atm/mol K

T = temperature

Substitute the values into above formula as follows.

$PV = nRT\\1 atm \times 0.372 L = n \times 0.0821 L atm/mol K \times 273.15 K\\n = 0.0165 mol$

2). As number of moles are also equal to mass of a substance divided by its molar mass.

So, number of moles of Arsine $(AsH_{3})$ (molar mass = 77.95 g/mol) is as follows.

$No. of moles = \frac{mass}{molar mass}\\0.0165 mol = \frac{mass}{77.95 g/mol}\\mass = 1.286 g$

Density is the mass of substance divided by its volume. Hence, density of arsine is calculated as follows.

$Density = \frac{mass}{volume}\\= \frac{1.286 g}{0.372 L}\\= 3.45 g/L$

Thus, we can conclude that 0.0165 moles of gaseous arsine (AsH3) occupy 0.372 L at STP and the density of gaseous arsine is 3.45 g/L.

4 0

3 years ago

is the general formula of a certain hydrate. When 256.3 g of the compound is heated to drive off the water, 214.2 g of anhydrous

Marizza181 [45]

Answer:

The general formula of the hydrate is Caa Seb Oc. nH2O. Based on the given information, the weight of the hydrated compound is 256.3 grams, the weight of the anhydrous compound is 214.2 grams.

Therefore, the weight of water evaporated is 256.3 g - 214.2 g = 42.1 grams

The molecular weight of water is 18 gram per mole. So, the number of moles of water will be,

Moles of water = weight of water/molecular weight

= 42.1 grams / 18 = 2.3

The given composition of calcium is 21.90 %. So, the concentration of calcium in anhydrous compound is,

= 214.2 * 0.2190 = 46.91 grams

The given composition of Se is 43.14 %. So, the concentration of selenium in anhydrous compound is,

= 214.2 * 0.4314 = 92.40 grams

The given composition of oxygen is 34.97%, So, the concentration of oxygen in anhydrous compound is,

= 214.2 * 0.3497 = 74.91 grams

The molecular weight of Ca is 40.078, the obtained concentration is 46.91 grams, stoichiometry will be, 46.91/40.078 = 1.17

The molecular weight of Se is 78.96, the obtained concentration is 92.40, stoichiometry will be,

92.40/78.96 = 1.17

The molecular weight of Oxygen is 15.999, the concentration obtained is 74.91, the stoichiometry will be,

74.91/15.999 = 4.68.

Thus, the formula becomes, Ca1.17. Se1.1e O4.68. 2.3H2O, the closest actual component is CaSeO4.2H2O

6 0

4 years ago

Protons are located

Lyrx [107]

<span>(C) in the nucleus with neutrons
</span>

7 0

3 years ago

What is the pH of a solution that has a [H+] = 0.010 mol/L?

Serjik [45]

Answer:

pH = 2

A 0.010 M solution of hydrochloric acid, HCl, has a molarity of 0.010 M. This means that [H+] = 1 x 10-2 M. The pH of this aqueous solution of H+ ions is pH = 2

hope this helps :3

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5 0

3 years ago