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3 years ago

Help i know whofkfkfkf

Chemistry

1 answer:

Irina18 [472]3 years ago

7 0

Answer:-

1. A compound contains atoms of different elements chemically combined together in a fixed ratio. An element is a pure chemical substance made of same type of atom. ... Elements that compose the compound are chemically combined. Elements contain only one type of atom.

2. Two ways to add energy to break down a compound are to apply heat and to apply an electric current.

3. The compound composed of these ions exhibits properties entirely different from the properties of the elements sodium and chlorine. Chlorine is poisonous, but sodium chloride is essential to life; sodium atoms react vigorously with water, but sodium chloride simply dissolves in water.

4. In chemistry, the law of definite proportion, sometimes called Proust's law, or law of constant composition states that a given chemical compound always contains its component elements in fixed ratio (by mass) and does not depend on its source and method of preparation.

5. compounds and elements.

6.Solid nonmetals

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A cyclist rode at an average speed of 10 mph for 15 miles. How long was the ride?

xxMikexx [17]

If the cyclist rode at an average speed of 10mph for 15 miles...

we can solve by dividing the distance by the speed to get time using the equation...

Δspeed = Δdistance / Δtime

Δtime = Δdistance / Δspeed

Δtime = 15 miles / 10 mph = 1.5 hours

7 0

3 years ago

Read 2 more answers

Part complete When a 235 92U nucleus is bombarded by neutrons (10n) it undergoes a fission reaction, resulting in the formation

nikdorinn [45]

Answer: The isotopic symbol of barium is $_{56}^{138}\textrm{Ba}$ and that of strontium is $_{38}^{89}\textrm{Sr}$

Explanation:

Nuclear fission reactions are defined as the reactions in which a heavier nuclei breaks down in two or more smaller nuclei.

In a nuclear reaction, the total mass and total atomic number remains the same.

For the given fission reaction:

$^{235}_{92}\textrm{U}+^1_0\textrm{n}\rightarrow ^A_Z\textrm{Ba}+^{94}_{36}\textrm{Kr}+3^1_0\textrm{n}$

To calculate A:

Total mass on reactant side = total mass on product side

235 + 1 = A + 94 + 3

A = 139

To calculate Z:

Total atomic number on reactant side = total atomic number on product side

92 + 0 = Z + 36 + 0

Z = 56

The isotopic symbol of barium is $_{56}^{139}\textrm{Ba}$

For the given fission reaction:

$^{235}_{92}\textrm{U}+^1_0\textrm{n}\rightarrow ^A_Z\textrm{Sr}+^{143}_{54}\textrm{Xe}+3^1_0\textrm{n}$

To calculate A:

Total mass on reactant side = total mass on product side

235 + 1 = A + 143 + 3

A = 90

To calculate Z:

Total atomic number on reactant side = total atomic number on product side

92 + 0 = Z + 54 + 0

Z = 38

The isotopic symbol of strontium is $_{38}^{89}\textrm{Sr}$

Hence, the isotopic symbol of barium is $_{56}^{138}\textrm{Ba}$ and that of strontium is $_{38}^{89}\textrm{Sr}$

7 0

3 years ago

True or false. (Pls help)

grigory [225]

I believe they’re both true.

5 0

3 years ago

Read 2 more answers

The conversion of cyclopropane to propene occurs with a first-order rate constant of . How long will it take for the concentrati

Gennadij [26K]

This is an incomplete question, here is a complete question.

The conversion of cyclopropane to propene occurs with a first-order rate constant of 2.42 × 10⁻² hr⁻¹. How long will it take for the concentration of cyclopropane to decrease from an initial concentration 0.080 mol/L to 0.053 mol/L?

Answer : The time taken will be, 17.0 hr

Explanation :

Expression for rate law for first order kinetics is given by:

$t=\frac{2.303}{k}\log\frac{a}{a-x}$

where,

k = rate constant = $2.42\times 10^{-2}\text{ hr}^{-1}$

t = time passed by the sample = ?

a = initial concentration of the reactant = 0.080 M

a - x = concentration left = 0.053 M

Now put all the given values in above equation, we get

$t=\frac{2.303}{2.42\times 10^{-2}}\log\frac{0.080}{0.053}$

$t=17.0\text{ hr}$

Therefore, the time taken will be, 17.0 hr

5 0

3 years ago

How do you find a theoretical mass? Is there a difference between theoretical mass and theoretical yield?

swat32

Theoretical yield is the quantity of a product obtained from the complete conversion of the limiting reactant in a chemical reaction. It is the amount of product resulting from a perfect chemical reaction and thus not the same as the amount you'll actually get from a reaction.

3 0

4 years ago