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liberstina [14]
3 years ago
9

What are the alkaline earth metals?

Chemistry
1 answer:
Evgesh-ka [11]3 years ago
3 0
The answer is A. Group 2 elements
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In an experiment, a 0.5297 g sample of diphenylacetylene (C14H10) is burned completely in a bomb calorimeter. The calorimeter is
V125BC [204]

Answer:

the Molar heat of  Combustion  of  diphenylacetylene (C_{14}H_{10})  = -6.931 *10^3 \ kJ/mol

Explanation:

Given that:

mass of diphenylacetylene (C_{14}H_{10}) = 0.5297 g

Molar Mass of diphenylacetylene (C_{14}H_{10}) = 178.21 g/mol

Then number of moles of diphenylacetylene (C_{14}H_{10})  = \frac{mass}{molar \ mass}

= \frac{0.5297  \ g }{178.24 \  g/mol}

= 0.002972 mol

By applying the law of calorimeter;

Heat liberated by 0.002972 mole of diphenylacetylene (C_{14}H_{10})  = Heat absorbed by H_2O + Heat absorbed  by the calorimeter

Heat liberated  by 0.002972 mole of diphenylacetylene (C_{14}H_{10})  =  msΔT + cΔT

= 1369 g  × 4.184 J g⁻¹°C⁻¹ × (26.05 - 22.95)°C + 916.9 J/°C (26.05 - 22.95)°C

= 17756.48 J + 2842.39 J

= 20598.87 J

Heat liberated by 0.002972 mole of diphenylacetylene (C_{14}H_{10})  = 20598.87 J

Heat liberated by 1 mole of  diphenylacetylene (C_{14}H_{10}) will be = \frac{20598.87 \ J}{0.002972 \ mol}

= 6930979.139 J/mol

= 6930.98 kJ/mol

Since heat is liberated ; Then, the Molar heat of  Combustion  of  diphenylacetylene (C_{14}H_{10})  = -6.931 *10^3 \ kJ/mol

3 0
3 years ago
Read 2 more answers
Consider the following types of electromagnetic radiation:
liq [111]

Explanation:

Electromagnetic wave              Wavelength

(1) Microwave  =   1 m to 1 mm = 10^9 nm to 10^6 nm

(2) Ultraviolet  =    10 nm to 400 nm

(3) Radio waves  =   1 mm to 100 km = 10^6 nm to 10^{14}nm

(4) Infrared  =    700 nm to 1 mm

(5) X-ray  =   0.01 nm to 10 nm

(6) Visible =   400 nm t0 700 nm

a) In order of increasing wavelength:

: 5 < 2 < 6 < 4 < 1 < 3

b) Frequency of the electromagnetic wave given as:

\nu=\frac{c}{\lambda }

\nu = frequency

\lambda = Wavelength

c = speed of light

\nu \propto \frac{1}{\lambda }

So, the increasing order of frequency:

: 3 < 1 < 4 < 6 < 2 < 5

c) Energy(E) of the electromagnetic wave is given by Planck's equation :

E=h\nu

E\propto \nu

So, the increasing order of energy:

: 3 < 1 < 4 < 6 < 2 < 5

6 0
3 years ago
A substance is made up of slow-moving particles that have very little space between them. Based on this information, what can mo
spin [16.1K]

Answer:

o

Explanation:

it is not a gas because the particles do not move freely it may be a liquid or a solid partly and mostly liquidized.

8 0
3 years ago
What happens when an electron moves from a high energy level to a lower one? it absorbs light it emits light it disappears it ge
Marianna [84]

Answer: The correct answer is it emits light.

Explanation:

When an electron is present in ground level that is the lower energy level and moves to the higher energy level, the energy is provided to the electron which means that it absorbs light. This is known as absorption.

When an electron present in the higher energy level comes back to the lower energy level, it emits radiations in the form of light. This is known as emission.

Hence, the correct answer is it emits light.

8 0
3 years ago
Helpppppp helpppppp helppppp​
soldier1979 [14.2K]

where is the diagram?

without the diagram i can't help

7 0
3 years ago
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