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3 years ago

The most familiar elements are typically the most

Chemistry

2 answers:

egoroff_w [7]3 years ago

5 0

Explanation:

The most familiar elements are the ones most abundant in the earth and therefore the most economic ones. Good examples of this elements are oxygen, carbon, nitrogen silicium.

rodikova [14]3 years ago

4 0

-Are the most used in daily life and basic human needs

(such as oxygen,nitrogen,carbon, etc)

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Plants are living organisms that respond to stimuli, use resources for energy, grow and develop, are organized by cells, and rep

Andreas93 [3]

Answer:

true

Explanation:

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2 years ago

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When 1.045 g of CaO is added to 50.0 mL of water at 25.0 °C in a calorimeter, the temperature of the water increases to 32.3 °C.

Rus_ich [418]

Answer:

1.71 kJ/mol

Explanation:

The expression for the calculation of the enthalpy change of a process is shown below as:-

$\Delta H=m\times C\times \Delta T$

Where,

$\Delta H$ is the enthalpy change

m is the mass

C is the specific heat capacity

$\Delta T$ is the temperature change

Thus, given that:-

Mass of CaO = 1.045 g

Specific heat = 4.18 J/g°C

$\Delta T=32.3-25.0\ ^0C=7.3\ ^0C$

So,

$\Delta H=1.045\times 4.18\times 7.3\ J=31.88713\ J$

Also, 1 J = 0.001 kJ

So,

$\Delta H=0.03189\ kJ$

Also, Molar mass of CaO = 56.0774 g/mol

$Moles=\frac{Mass}{Molar\ mass}=\frac{1.045}{56.0774}\ mol=0.01863\ mol$

Thus, Enthalpy change in kJ/mol is:-

$\Delta H=\frac{0.03189}{0.01863}\ kJ/mol=1.71\ kJ/mol$

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2 years ago

What is the mass of 0.28 mole of iron?

vredina [299]

Answer:

Your answer should be 15.68 grams.

Explanation:

Seeing as 1 mole has a mass of 56 g, 56*0.28 would get you 15.68 g.

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3 years ago

By replacing hardware safety features with software controls in the therac-25 machine, aecl was able to?

Ipatiy [6.2K]

Therac-25, AECL was able to reduce costs by replacing hardware safety features with software controls.

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2 years ago

Hydrates that have a low vapor pressure and remove moisture from air are said to be ___. Question 8 options: effloresce hygrosco

-Dominant- [34]

Answer:

Hygroscopic

Explanation:

An hygroscopic substance is one that absorbs moisture from the atmosphere and becomes wet. Their ability to remove water from air is less than that of deliquescent substances. Most of the solid hygroscopic substances forms pasty substances and not solutions like the deliquescent compounds.

Examples are sodium trioxonitrate(v), copper(ii) oxide e.t.c

Efflorescence compounds gives off their water of crystallization to the atmosphere.

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2 years ago