Which elements did the Curies discover?

There are two types of physical changes and chemical reactions- endothermic and exothermic. On the diagram below, which picture

Agata [3.3K]

Answer:

it is b because its releases heat in to all directions and not b because it staying inside and not releasing anything :)

Explanation:

6 0

3 years ago

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Nitrogen has the atomic number 7. an isotope of nitrogen containing seven neutrons would be

BigorU [14]

An isotope of nitrogen containing 7 neutrons would be nitrogen-7

8 0

3 years ago

A chemistry student must write down in her lab notebook the concentration of a solution of sodium hydroxide. The concentration o

taurus [48]

Answer:

The concentration the student should write down in her lab is 2.2 mol/L

Explanation:

Atomic mass of the elements are:

Na: 22.989 u

S: 32.065 u

O: 15.999 u

Molar mass of sodium thiosulfate, Na2S2O3 = (2*22.989 + 2*32.065 + 3*15.999) g/mol = 158.105 g/mol.

Mass of Na2S2O3 taken = (19.440 - 2.2) g = 17.240 g.

For mole(s) of Na2S2O3 = (mass taken)/(molar mass)

= (17.240 g)/(158.105 g/mol) = 0.1090 mole.

Volume of the solution = 50.29 mL = (50.29 mL)*(1 L)/(1000 mL)

= 0.05029 L.

To find the molar concentration of the sodium thiosulfate solution prepared we use the formula:

= (moles of sodium thiosulfate)/(volume of solution in L)

= (0.1090 mole)/(0.05029 L)

= 2.1674 mol/L

6 0

3 years ago

Explain the reaction of metals with water.<br><br>

telo118 [61]

Answer:

it rusts

Explanation:

4 0

3 years ago

For each balanced reaction, indicate the total number of atoms in the table below.

Afina-wow [57]

(i) Make ammonia number of atoms on reactant side is 8 and on product side is 8. (ii) Separate water number of atoms on reactant side is 6 and on product side is 6. (iii) Combust methane number of atoms on reactant side is 9 and number of atoms on product side is 9.

<h3>What is Balanced Chemical Equation ?</h3>

The balanced chemical equation is the equation in which the number of atoms on the reactant side is equal to the number of atoms on the product side in an equation.

(i) Make Ammonia

First we have to write the balanced chemical equation

N₂ + 3H₂ → 2NH₃

Reactant side Product side

N = 2 N = 2

H = 6 H = 6

So total number of atoms on product and reactant side is 8.

(ii) Separate Water

First we have to write the balanced chemical equation

2H₂O → 2H₂ + O₂

Reactant side Product side

H = 4 H = 4

O = 2 O = 2

So total number of atoms on product and reactant side is 6.

(iii) Combust methane

First we have to write the balanced chemical equation

CH₄ + 2O₂ → 2H₂O + CO₂

Reactant side Product side

C = 1 C = 1

H = 4 H = 4

O = 4 O = 4

So total number of atoms on product and reactant side is 9.

Thus from the above conclusion we can say that For each balanced reaction, the total number of atoms are

Reaction Total number of atoms

Reactant side Product side

Make Ammonia 8 8

Separate Water 6 6

Combust Methane 9 9

Learn more about the Balanced Chemical Equation here: brainly.com/question/26694427

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Disclaimer: The question was given incomplete on the portal. Here is the complete question.

Question: For each balanced reaction, indicate the total number of atoms in the table below.

Reaction Total number of atoms

Reactant side Product side

Make Ammonia _________ __________

Separate Water _________ __________

Combust Methane _________ __________

3 0

2 years ago