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2 years ago

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Stars were classified first by the strength of the hydrogen lines in their spectra, and then by temperature. Which arrangement o

f stellar types is in order of the strength of their hydrogen lines, from strongest to weakest?

1 answer:

zzz [600]2 years ago

3 0

sorry, don't know

sorry, don't know

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I need help pls Where does it belong to?

Daniel [21]

The answer is B. Fungi,Protists

6 0

2 years ago

The airbags that protect people in car crashes are inflated by the extremely rapid decomposition of sodium azide, which produces

Oxana [17]

Answer:

1. NaN₃(s) → Na(s) + 1.5 N₂(g)

2. 79.3g

Explanation:

<em>1. Write a balanced chemical equation, including physical state symbols, for the decomposition of solid sodium azide (NaN₃) into solid sodium and gaseous dinitrogen.</em>

NaN₃(s) → Na(s) + 1.5 N₂(g)

<em>2. Suppose 43.0L of dinitrogen gas are produced by this reaction, at a temperature of 13.0°C and pressure of exactly 1atm. Calculate the mass of sodium azide that must have reacted. Round your answer to 3 significant digits.</em>

First, we have to calculate the moles of N₂ from the ideal gas equation.

$P.V=n.R.T\\n=\frac{P.V}{R.T} =\frac{1atm.(43.0L)}{(0.08206atm.L/mol.K).286.2K} =1.83mol$

The moles of NaN₃ are:

$1.83molN_{2}.\frac{1molNaN_{3}}{1.5molN_{2}} =1.22molNaN_{3}$

The molar mass of NaN₃ is 65.01 g/mol. The mass of NaN₃ is:

$1.22mol.\frac{65.01g}{mol} =79.3g$

5 0

2 years ago

The equation shows one mole of ethanol fuel being burned in oxygen. Convert the energy released into its equivalent mass. C2H5OH

lana [24]

Answer:

47.9 g of ethanol

Explanation:

Combustion is a chemical reaction in which a substance reacts with oxygen to produce heat and light. Combustion reactions have been very useful as a source of energy. Ethanol is now burnt for energy purposes as a fuel. Ethanol has even been proposed as a possible alternative to fossil fuels.

Since 1 mole of ethanol when combusted releases 1367 kJ/mol of energy

x moles of ethanol releases 1418 kJ/mol.

x= 1 × 1418 kJ/mol/ 1367 kJ/mol

x= 1.04 moles of ethanol.

Mass of ethanol = number of moles × molar mass

Molar mass of ethanol = 46.07 g/mol

Mass of ethanol = 1.04 moles × 46.07 g/mol

Mass of ethanol= 47.9 g of ethanol

7 0

2 years ago

How many total atoms are there in one molecule of C145H293O168?

nasty-shy [4]

Answer:

606 atoms

Explanation:

Add the numbers 145 + 293 + 168

4 0

2 years ago

The amount of a harmful chemical to which a person is exposed is the ____.

kotykmax [81]

A. dose
a dose is an amount, a response is an action, and pollutant and toxins are substances

6 0

3 years ago

Read 2 more answers