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3 years ago

How do scientists distinguish between an element and a compound?

1 answer:

8 0

An element is just consisted of one type of atom and cannot be broken down by chemicals (Ex. Oxygen just has the oxygen molecule)

A compound is when there's a mixture of atoms and can be broken down by chemicals (Ex. NaCl is made up of sodium and chloride atoms)

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A wave is moving toward the shore If its frequency is 2.7 hertz, what is its wavelength? What would the correct number of signif

ArbitrLikvidat [17]

Answer:

λ = 1.1×10⁸ m

Explanation:

Given data:

Frequency of wave = 2.7 Hz

Wavelength of wave = ?

Solution:

Formula:

Speed of wave = frequency × wavelength

Speed of wave = 3×10⁸ m/s

now we will put the values in formula.

3×10⁸ m/s = 2.7 s⁻¹ × λ

λ = 3×10⁸ m/s /2.7 s⁻¹

λ = 1.1×10⁸ m

7 0

2 years ago

Cutting, melting, bending, or crushing are examples of what kind of change?

Ksivusya [100]

Answer:

those are all physical changes and most physical changes can be undone like crushing a pice of metal you can flatten it back out you anwser is physical change

Explanation:

8 0

3 years ago

Read 2 more answers

(a) What is the total volume (in L) of gaseous products, measured at 350°C and 735 torr, when an automobile engine burns 100. g

Anarel [89]

Answer:

Part A

The volume of the gaseous product is $V = 787L$

Part B

The volume of the the engine’s gaseous exhaust is $V_e = 2178 \ L$

Explanation:

Part A

From the question we are told that

The temperature is $T = 350^oC = 350 +273 =623K$

The pressure is $P = 735 \ torr = \frac{735}{760} = 0.967\ atm$

The of $C_8 H_{18} = 100.0g$

The chemical equation for this combustion is

$2 C_8 H_{18}_{(l)} + 25O_2_{(l)} ----> 16CO_2_{(g)} + 18 H_2 O_{(g)}$

The number of moles of $C_8 H_{18}$ that reacted is mathematically represented as

$n = \frac{mass \ of \ C_8H_{18} }{Molar \ mass \ of C_8H_{18} }$

The molar mass of $C_8 H_{18}$ is constant value which is

$M = 114.23 \ g/mole$

So $n = \frac{100 }{114.23} }$

$n = 0.8754 \ moles$

The gaseous product in the reaction is $CO_2_{(g)}$ and water vapour

Now from the reaction

2 moles of $C_8 H_{18}$ will react with 25 moles of $O_2$ to give (16 + 18) moles of $CO_2_{(g)}$ and $H_2 O_{(g)}$

1 mole of $C_8 H_{18}$ will react with 12.5 moles of $O_2$ to give 17 moles of $CO_2_{(g)}$ and $H_2 O_{(g)}$

This implies that

0.8754 moles of $C_8 H_{18}$ will react with (12.5 * 0.8754 ) moles of $O_2$ to give (17 * 0.8754) of $CO_2_{(g)}$ and $H_2 O_{(g)}$

So the no of moles of gaseous product is

$N_g = 17 * 0.8754$

$N_g = 14.88 \ moles$

From the ideal gas law

$PV = N_gRT$

making V the subject

$V = \frac{N_gRT}{P}$

Where R is the gas constant with a value $R = 0.08206 \ L\cdot atm /K \cdot mole$

Substituting values

$V = \frac{14.88* 0.08206 *623}{0.967}$

$V = 787L$

Part B

From the reaction the number of moles of oxygen that reacted is

$N_o = 0.8754 * 12.5$

$N_o = 10.94 \ moles$

The volume is

$V_o = \frac{10.94 * 0.08206 *623}{0.967}$

$V_o = 579 \ L$

No this volume is the 21% oxygen that reacted the 79% of air that did not react are the engine gaseous exhaust and this can be mathematically evaluated as

$V_e = V_o * \frac{0.79}{0.21}$