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3 years ago

A.Which non-metal is essential for our life and all living beings inhale it during breathing?

Chemistry

2 answers:

vodomira [7]3 years ago

6 0

Answer:

A. oxygen

B. chlorine

2. iodine

(a) because aluminium is a soft malleable metal. it can be made to in sheets to form thin wrapping sheets. also, it does not react with food items.

(b) because metals are good conductors of heat and electricity. the immersion rod needs electric supply to get heated and to heat liquids.

(c) they're kept in kerosene to keep them from coming in contact with oxygen and moisture as they react to form their hydroxides.

4. Magnesium is a metal. Metals react with oxygen to form metallic oxides. So Magnesium oxides are basic in nature. But nonmetals react with oxygen to form nonmetallic oxides. These oxides differ from metallic oxides because they are acidic in nature. Nonmetallic oxides react with water to form acids. Therefore, Sulphur dioxide is acidic in nature. Magnesium oxide is basic in nature.

5. Copper forms a green deposit on its surface when exposed to air which is usually a mixture of copper carbonate and copper hydroxide. It's acidic in nature.

Mandarinka [93]3 years ago

5 0

Answer:

2.A

Explanation:

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Which description of salt is a physical property?

Nonamiya [84]

Answer:

White being the color and coming in small grains.

Explanation:

Physical properties are something you can clearly see about the object.

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2 years ago

Read 2 more answers

Help me please for brainliest and 10 points.

Stella [2.4K]

Answer:

The red arrow from igneous to sedimentary rock

Explanation:

When rocks are weathered and eroded, they become sediment. This sediment is later compacted and cemented to form sedimentary rock. Therefore, the red arrow going from igneous rock to sedimentary rock represents weathering and erosion.

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4 years ago

Stearic acid (C18H36O2) is a fatty acid, a molecule with a long hydrocarbon chain and an organic acid group (COOH) at the end. I

Paha777 [63]

Answer:

There is 9671 Kj of heat released

Explanation:

Step 1: The balanced equation:

C18H36O2(s) + 26O2(g) --> 18CO2(g)+18H2O(g)

This means for 1 mole of C18H36O2 consumed there is 26 moles of O2 needed to produce 18 moles of CO2 and 18 moles of H2O.

Step 2: Calculate the heat of combustion

ΔH (combustion) = [18*(ΔHf of CO2) + 18*(ΔHf of H2O)] - [1*(ΔHf of C18H36O2) + 26*(ΔHf of O2)]

ΔH (combustion) = [18*(-394 kJ/mol) + 18*(-242 kJ/mol)] - [1*(-948 kJ/mol) + 26*(0 kJ/mol)]

ΔH (combustion) = [(-7092 kJ/mol) + (-4356 kJ/mol)] - (-948 kJ/mol)

= -10500 kJ/mol

ΔH (combustion) = heat released / number of moles of stearic acid

Step 3: Calculate moles of stearic acid

moles of stearic acid = mass / Molar mass of stearic acid

moles of stearic acid = 262g / 284.48 g/mole = 0.921 moles

Step 4: Calculate moles of oxygen

moles of O2 = 914.5 / 32g/mole

moles of O2 = 28.578125 moles

Stearic acid is the limiting reactant: it will completely react

There will react 26*0.921 mole = 23.946 mole of O2

This means there will remain 4.63 moles of O2

Step 5: Calculate heat released

q = (ΔH combustion) * (moles of stearic acid) = (-10500 kJ/mol) * (0.921 moles) = 9671 Kj

There is 9671 Kj of heat released

6 0

3 years ago

Which of the following objects would be the best conductor of electricity?

earnstyle [38]

Answer:

A safety pin

Explanation:

Rubber, plastic and food are all non-metals, meaning they are poor conductors of heat and electricity. However, safety pins are made up of steel - a metal - making them good conductors.

4 0

2 years ago

Where does the formation of rocks began

bekas [8.4K]

Hi!

All rocks are connected in a cycle of creation, change, and destruction called the Rock Cycle. The rock cycle begins with molten rock (magma below ground, lava above ground), which cools and hardens to form igneous rock.

Hope this helps!

~CoCo

7 0

3 years ago