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3 years ago

Consider this statement: Earth is the only source of gravity in the solar system. Do you agree? Give your reasons.

1 answer:

6 0

No, everything with a mass has gravity. That's why the planets orbit the sun. That's why moons orbit planets. The asteroid belt etc etc. If you drop something heavy on the moon, it'll still fall to the ground, this proves that there is gravity on the moon. The Mars rover is still on Mars, it hasn't floated away, this proves there is gravity on Mars.

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Formula for Sodium Hydrogen Carbonate NaHCO3? or Na2HCO3?

yan [13]

NaHCO3 is the right answer

8 0

3 years ago

Base changes phenolphthalein to pink it is true or false

galben [10]

Answer:

It’s false

Explanation:

it could be true if the question mentioned alkaline solution

4 0

2 years ago

Read 2 more answers

For a particular isomer of C 8 H 18 , C8H18, the combustion reaction produces 5104.1 kJ 5104.1 kJ of heat per mole of C 8 H 18 (

vlada-n [284]

Answer:

The standard enthalpy of formation of this isomer of octane is -220.1 kJ/mol

Explanation:

Step 1: Data given

The combustion reaction of octane produces 5104.1 kJ per mol octane

Step 2: The balanced equation

C8H18(g) + 12.5 O2 ⟶ 8CO2 (g) + 9 H2O (g) ∆H°rxn = -5104.1 kJ/mol

Step 3:

∆H°rxn = ∆H°f of products minus the ∆H° of reactants

∆H°rxn = ∆H°f products - [∆H°f reactants]

-5104.1 kJ/mol = (8*∆H°fCO2 + 9*∆H°fH20) - (∆H°fC8H18 + 12.5∆H°fO2)

∆H°f C8H18 = ∆H°f 8CO2 + ∆H°f 9H2O+ 5104.1 kJ/mol

∆H°f C8H18 = 8 * (-393.5 kJ)/mol + 9 * (-241.8 kJ/mol)] + 5104.1 kJ /mol

∆H°f C8H18 = -220.1 kJ/mol

The standard enthalpy of formation of this isomer of octane is -220.1 kJ/mol

7 0

3 years ago

Strontium-90 is a radioisotope that will decrease in mass by one-half every 29 years. How many years will it take for a 10.0-gra

Lelechka [254]

Answer: It will take 29 years for a 10.0-gram sample of strontium-90 to decay to 5.00 grams

Explanation:

Radioactive decay process is a type of process in which a less stable nuclei decomposes to a stable nuclei by releasing some radiations or particles like alpha, beta particles or gamma-radiations. The radioactive decay follows first order kinetics.

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

Half life is represented by $t_{\frac{1}{2}$

$t_{\frac{1}{2}=\frac{0.693}{\lambda}$

$\lambda$ = rate constant

Given : Strontium-90 decreases in mass by one-half every 29 years , that is half life of Strontium-90 is 29 years.

As half life is independent of initial concentration, it will take 29 years for a 10.0-gram sample of strontium-90 to decay to 5.00 grams as the amount gets half.

7 0

3 years ago

Calculate the mass of 488 moles of calcium carbonate

san4es73 [151]

Answer: 48800g

Explanation:

Using the mathematical relation : Moles = Mass / Molar Mass

Moles = 488

Molar mass of CaCO3 = 40 + 12 + (16 x 3) = 100g/mol

Therefore

488 = mass / 100 = 48800g

6 0

3 years ago