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2 years ago

Umm care to help, please

Chemistry

2 answers:

marysya [2.9K]2 years ago

4 0

Answer:

17.5

Explanation:

Archy [21]2 years ago

3 0

Explanation:

Protons (the atomic number) and neutrons both contribute to the atomic mass.

If you therefore subtract the number of protons (19) from the atomic mass (39), you are left with the number of neutrons (=20).

hope this helped :)

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(Direct answer=Upvote cause I aint smart xD)

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3 years ago

Why do elements that make positive ions occur on the left side of the periodic table while those that make negative ions occur o

Lynna [10]

Answer:

Elements in the same group have the same number of valence electrons.

Explanation: Science.

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3 years ago

What is litmus paper used for? To indicate if all the reactants have been used up to determine if a chemical reaction has occurr

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The main use of litmus is to test whether a solution is acidic or basic. Blue litmus paper turns red under acidic conditions and red litmus paper turns blue under basic or alkaline conditions, with the color change occurring over the pH range 4.5–8.3 at 25 °C (77 °F).

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3 years ago

Fe(NO3)2 not sure how to get the oxidation numbers of all elements

Cloud [144]

Fe(NO3)2
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3 years ago

Assume that you have a cylinder with a movable piston. What would happen to the gas pressure inside the cylinder if you do the f

pishuonlain [190]

Answer:

A. The pressure will increase 4 times. P₂ = 4 P₁

B. The pressure will decrease to half its value. P₂ = 0.5 P₁

C. The pressure will decrease to half its value. P₂ = 0.5 P₁

Explanation:

Initially, we have n₁ moles of a gas that occupy a volume V₁ at temperature T₁ and pressure P₁.

What would happen to the gas pressure inside the cylinder if you do the following?

Part A: Decrease the volume to one-fourth the original volume while holding the temperature constant. Express your answer in terms of the variable P initial.

V₂ = 0.25 V₁. According to Boyle's law,

P₁ . V₁ = P₂ . V₂

P₁ . V₁ = P₂ . 0.25 V₁

P₁ = P₂ . 0.25

P₂ = 4 P₁

Part B: Reduce the Kelvin temperature to half its original value while holding the volume constant. Express your answer in terms of the variable P initial.

T₂ = 0.5 T₁. According to Gay-Lussac's law,

$\frac{P_{1}}{T_{1}} =\frac{P_{2}}{T_{2}}\\\frac{P_{1}}{T_{1}} =\frac{P_{2}}{0.5T_{1}}\\\\P_{2}=0.5P_{1}$

Part C: Reduce the amount of gas to half while keeping the volume and temperature constant. Express your answer in terms of the variable P initial.

n₂ = 0.5 n₁.

P₁ in terms of the ideal gas equation is:

$P_{1}=\frac{n_{1}.R.T_{1}}{V_{1}}$

P₂ in terms of the ideal gas equation is:

$P_{2}=\frac{n_{2}.R.T_{1}}{V_{1}}=\frac{0.5n_{1}.R.T_{1}}{V_{1}}=0.5P_{1}$

3 0

3 years ago