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2 years ago

What kind of change took place when the magnesium was heated?

Chemistry

2 answers:

nirvana33 [79]2 years ago

7 0

Explanation:

<h2>hope is help...brainliest,heart</h2>

Dmitrij [34]2 years ago

6 0

Answer:

You can see that it is an endothermic reaction or heat is being absorbed for the change from magnesium to magnesium oxide. So it is an endothermic reaction. So these are the four reasons why we can say that burning of magnesium ribbon in the air is considered a chemical change.

Explanation:

hope it help

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Week 4 learning task 1 science 4th quarter

cestrela7 [59]

Answer:

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Explanation:

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2 years ago

A. Calculate the empirical formula of a molecule with percent compositions: 55.3% potassium (K), 14.6% phosphorus (P), and 30.1%

Otrada [13]

The way you calculate the empirical formula is to firstly assume 100g. To find each elements moles you take each elements percentage listed, times it by one mole and divide it by its atomic mass. (ex: moles of K =55.3g x 1 mole/39.1g, therefore there is 1.41432225 moles of Potassium) Once you’ve completed this for every element you list each elements symbol beside it’s number of moles and divide by the smallest number because it can only go into its self once. After you’ve done this, you’ve found your empirical formula, which is the simplest whole number ratio of atoms in a compound. I’ve added an example of a empirical question I completed last semester :)

6 0

3 years ago

Read 2 more answers

Come up with 2 examples of derived units from everyday life.

kirill115 [55]

Answer:

answer

Explanation:

Area : Square Meters,

Volume : Cubic Meters,

Density : Kilograms per Meter Cube,

Velocity : Meters per Second Squared,

Force : Newtons (Mass multiplied by Acceleration or Mass multiplied by Displacement divided by Time squared)…..

5 0

2 years ago

How many moles of methane (CH4) is 6.70 x 1022 atoms of methane?

suter [353]

Answer:

0.1113 mol

Explanation:

Data Given:

no. of atoms of CH₄= 6.70 x 10²² atoms

no. of moles of methane (CH₄) = ?

Solution:

we will find no. of moles of methane (CH₄)

Formula used

no. of moles = no. of atoms / Avogadro's number

Where

Avogadro's number = 6.022 x 10²³

Put values in above equation

no. of moles = 6.70 x 10²² atoms / 6.022 x 10²³ (atoms/mol)

no. of moles = 0.1113 mol

So,

There are 0.1113 moles of methane.

8 0

3 years ago

Consider the reaction between hydrazine and hydrogen to produce ammonia, N2H4(g)+H2(g)→2NH3(g). Use enthalpies of formation and

kupik [55]

Answer:

The enthalpy of the nitrogen-nitrogen bond in N2H4 is 162.6 kJ

Explanation:

For the reaction: N2H4(g)+H2(g)→2NH3(g), the enthalpy change of reaction is

ΔH rxn = 2 ΔHºf NH3 - ΔHºf N2H4

but we also know that the ΔH rxn is calculated by accounting the sum of number of bonds formed and bonds broken as follows:

ΔH rxn = 6H (N-H) + 4 (N-H) + 2H (H-H)

where H is the bond enthalpy .When bonds are broken H is positive, and negative when formed, in the product there are 6 N-H bonds , and in the reactants 4 N-H and 1 H-H bonds).

Consulting an appropiate reference handbook or table the following values are used:

ΔHºf (NH3) = -46 kJ/mol

ΔHºf (N2H4) = 95.94 kJ/mol

(The enthalpy of fomation of hydrogen in its standard state is zero)

H (N-H) = 391 kJ

H (H-H) = 432 kJ

H (N-N) = ?

So plugging our values:

ΔH rxn = 2mol ( -46.0 kJ/mol) - 1mol(95.4 kJ/mol) = -187.40 kJ

-187.40 kJ = 6(-391 kJ) + 4 (391 kJ) + 432 + H(N-N)

-187.40 kJ = -350 kJ + H(N-N)

H(N-N) = 162.6 kJ

7 0

2 years ago