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3 years ago

The ancient Egyptians used black eye make up with which element just give me an element don’t give me a definition

Chemistry

1 answer:

Kay [80]3 years ago

3 0

Answer:

galena

Explanation:

The green eye paint was made of malachite, a copper carbonate pigment, and the black kohl was made from galena, a dark grey ore.

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1. Calculate the energy change (q) of the surroundings (water) using the enthalpy equation

Rasek [7]

Answer:

Q1: 728.6 J.

Q2:

a) 668.8 J.

b) 0.3495 J/g°C.

Explanation:

Q1: Calculate the energy change (q) of the surroundings (water) using the enthalpy equation:

The amount of heat absorbed by water = Q = m.c.ΔT.

where, m is the mass of water (m = d x V = (1.0 g/mL)(24.9 mL) = 24.9 g).

c is the specific heat capacity of liquid water = 4.18 J/g°C.

ΔT is the temperature difference = (final T - initial T = 32.2°C - 25.2°C = 7.0°C).

∴ The amount of heat absorbed by water = Q = m.c.ΔT = (24.9 g)(4.18 J/g°C)(7.0°C) = 728.6 J.

Q2: Calculate the energy change (q) of the surroundings (water) using the enthalpy equation

qwater = m × c × ΔT.

We can assume that the specific heat capacity of water is 4.18 J / (g × °C) and the density of water is 1.00 g/mL. calculate the specific heat of the metal. Use the data from your experiment for the unknown metal in your calculation.

a) First part: the energy change (q) of the surroundings (water):

The amount of heat absorbed by water = Q = m.c.ΔT.

where, m is the mass of water (m = d x V = (1.0 g/mL)(25 mL) = 25 g).

c is the specific heat capacity of liquid water = 4.18 J/g°C.

ΔT is the temperature difference = (final T - initial T = 31.6°C - 25.2°C = 6.4°C).

∴ The amount of heat absorbed by water = Q = m.c.ΔT = (25 g)(4.18 J/g°C)(6.4°C) = 668.8 J.

b) second part:

Q water = Q unknown metal.

Q unknown metal = - 668.8 J. (negative sign due to the heat is released from the metal to the surrounding water).

Q unknown metal = - 668.8 J = m.c.ΔT.

m = 27.776 g, c = ??? J/g°C, ΔT = (final T - initial T = 31.6°C - 100.5°C = - 68.9°C).

- 668.8 J = m.c.ΔT = (27.776 g)(c)( - 68.9°C) = - 1914 c.

∴ c = (- 668.8)/(- 1914) = 0.3495 J/g°C.

3 0

4 years ago

PLEASE HELP!!! What is the most likely effect of air temperature differences between San Diego, California and Savannah, Georgia

mash [69]

The correct answer is - D. Savannah is more humid and has higher precipitation than San Diego.

Despite both Savannah and San Diego being on the coast of an ocean, they do have differences in the climate. Savannah comes out on the Atlantic coast, while San Diego comes out on the Pacific Coast. Savannah is influenced by warm and wet air masses all year round, while San Diego is predominantly influenced by dry air masses because of the colder ocean currents. Savannah has a relatively stable temperature throughout the year, and it also has solid amount of precipitation, with the humidity in the air being always high. San Diego, on the other side, is hot for most of the year during the days, but the nights are relatively cool. There's very little precipitation, and the humidity in the air is not as high as in Savannah.

8 0

3 years ago

I’m doing a molecular protfolio on Fentanyl, and I can’t get a definite answer on its polarity or its solubility. Any help is ap

densk [106]

Answer: Fentanyl is a polar molecule.

Explanation:

Oxygen being electro-negative will attract electron pairs towards itself and partial positive charge will generate on carbon atom in (C=O) bond.

Due to partial positive charge on carbon atom of (C=O) group will tend to attract electron pairs from its neighboring atoms by which lone pair on nitrogen atom will come in conjugation with (C=O) group which leaves partial positive charge on nitrogen atom.

Now partial positive charge is on the nitrogen atom which will further withdraws the electron density from the phenyl ring attached to it and positive charge will get de-localize at ortho and para positions in phenyl ring.

Hence, making the molecule of fentanyl polar.

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3 years ago

How many atoms are in 20.6 moles of curium

Harman [31]

Answer: 1.24 × 10^25

Explanation:

$\frac{20.6 moles}{1}$ × $\frac{6.022 * 10^{24} }{1 Mole}$

Using our knowledge in unit conversions, we know the mole units cancel each other out and all there's left is the atom unit. From here we can multiply the fractions and eventually we end with the number 124.0532 × 10^23

According to the scientific notation rules, the number to the left of the decimal cannot exceed 10 so we have to move the decimal to the left two spaces. With this change, we also have to change the exponent of the 10. Because we moved the decimal point two spaces to the left, that means we have 10^25.

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3 years ago

What is usually needed to help a decomposition reaction occur

ArbitrLikvidat [17]

The addtion of energy is usually needed to help a decomposition reaction occur

3 0

3 years ago

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