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3 years ago

12

PLS HELP I NEED TO PASS THIS... In physical science lab, Kim and Dawn added small pieces of magnesium to hydrochloric acid. They

observed that bubbles formed, the test tube got hot, and the magnesium disappeared. What is a sign that a chemical reaction has taken place in this experiment?
Question 7 options:

A.odor

B.gas is produced

C.temperature decreased

D.magnesium appeared

1 answer:

Bond [772]3 years ago

8 0

B gas is produced is the answer.

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Calculate the solubility of hydrogen in water at an atmospheric pressure of 0.380 atm (a typical value at high altitude).

Pani-rosa [81]

The question is incomplete, here is the complete question:

Calculate the solubility of hydrogen in water at an atmospheric pressure of 0.380 atm (a typical value at high altitude).

Atmospheric Gas Mole Fraction kH mol/(L*atm)

$N_2$ $7.81\times 10^{-1}$ $6.70\times 10^{-4}$

$O_2$ $2.10\times 10^{-1}$ $1.30\times 10^{-3}$

Ar $9.34\times 10^{-3}$ $1.40\times 10^{-3}$

$CO_2$ $3.33\times 10^{-4}$ $3.50\times 10^{-2}$

$CH_4$ $2.00\times 10^{-6}$ $1.40\times 10^{-3}$

$H_2$ $5.00\times 10^{-7}$ $7.80\times 10^{-4}$

<u>Answer:</u> The solubility of hydrogen gas in water at given atmospheric pressure is $1.48\times 10^{-10}M$

<u>Explanation:</u>

To calculate the partial pressure of hydrogen gas, we use the equation given by Raoult's law, which is:

$p_{\text{hydrogen gas}}=p_T\times \chi_{\text{hydrogen gas}}$

where,

$p_A$ = partial pressure of hydrogen gas = ?

$p_T$ = total pressure = 0.380 atm

$\chi_A$ = mole fraction of hydrogen gas = $5.00\times 10^{-7}$

Putting values in above equation, we get:

$p_{\text{hydrogen gas}}=0.380\times 5.00\times 10^{-7}\\\\p_{\text{hydrogen gas}}=1.9\times 10^{-7}atm$

To calculate the molar solubility, we use the equation given by Henry's law, which is:

$C_{H_2}=K_H\times p_{H_2}$

where,

$K_H$ = Henry's constant = $7.80\times 10^{-4}mol/L.atm$

$p_{H_2}$ = partial pressure of hydrogen gas = $1.9\times 10^{-7}atm$

Putting values in above equation, we get:

$C_{H_2}=7.80\times 10^{-4}mol/L.atm\times 1.9\times 10^{-7}atm\\\\C_{CO_2}=1.48\times 10^{-10}M$

Hence, the solubility of hydrogen gas in water at given atmospheric pressure is $1.48\times 10^{-10}M$

4 0

3 years ago

Identify the correct descriptions of beta particles.

FrozenT [24]

Answer:

a. A beta particle has a negative charge. d. A beta particle is a high-energy electron.

Explanation:

Identify the correct descriptions of beta particles.

a. A beta particle has a negative charge. YES. A beta particle is originated in the following nuclear reaction: ¹₀n ⇒ ¹₁H + ⁰₋₁e (beta particle.)

b. A beta particle contains neutrons. NO. It is a electron originated in the nucleus.

c. A beta particle is less massive than a gamma ray. NO. Gamma rays don't have mass while a beta particle has a mass which is half of one thousandth of the mass of a proton.

d. A beta particle is a high-energy electron. YES. Beta particles are nuclear originated hig-energy electrons.

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3 years ago

How many grams of Sodium will have the same number of atoms as 6 grams of Magnesium?

Ksivusya [100]

Answer:

92gm

Explanation:

Atomic mass of Mg=24g=1 mole of Mg

∴ 24g =1 mole of Mg contain 6.022×10^23 atom

∴ 6gm contains 246.022×1023×6

=4×6.022×10^23 atoms

Now according to question, there are 6.022×1023 atoms of Na

23gm of Na contains 6.022×10^23 atoms

∴6.022×4×10^23 atoms of Na weighs 23×6.022×10^23×4/6.022×10^23⇒92gm

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3 years ago

Reactivity and flammability are are examples of properties.

nika2105 [10]

Answer:

they are eamples of chemical properties

Explanation:

flammibility is the chemical makeup of the element that makes it flamable and reactivitie is the chemical makeup of an element that is able to reacte to another element

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What is science......?

den301095 [7]

$\huge \underbrace \mathfrak \blue{Answer}$

<u>Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe. The earliest roots of science can be traced to Ancient Egypt and Mesopotamia in around 3000 to 1200 BCE.</u>

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3 years ago

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