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serg [7]
3 years ago
13

How does the fossil record suggest common ancestry?

Chemistry
1 answer:
Jobisdone [24]3 years ago
6 0

Answer:

  • the first one is: Fossils provide evidence that organisms from the past are not the same as those found today, and demonstrate a progression of evolution. Scientists date and categorize fossils to determine when the organisms lived relative to each other.
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Four balloons, each with a mass of 10.0 g, are inflated to a volume of 20.0 L, each with a different gas: helium, neon, carbon m
weeeeeb [17]
On temperature 25°C (298,15K) and pressure of 1 atm each gas has same amount of substance:
n(gas) = p·V ÷ R·T = 1 atm · 20L ÷ <span>0,082 L</span>·<span>atm/K</span>·<span>mol </span>· 298,15 K
n(gas) = 0,82 mol.
1) m(He) = 0,82 mol · 4 g/mol = 3,28 g.
d(He) = 10 g + 3,28 g ÷ 20 L = 0,664 g/L.
2) m(Ne) = 0,82 mol · 20,17 g/mol = 16,53 g.
d(Ne) = 26,53 g ÷ 20 L = 1,27 g/L.
3) m(CO) = 0,82 mol ·28 g/mol = 22,96 g.
d(CO) = 32,96 g ÷ 20L = 1,648 g/L.
4) m(NO) = 0,82 mol ·30 g/mol = 24,6 g.
d(NO) = 34,6 g ÷ 20 L = 1,73 g/L.
6 0
3 years ago
Read 2 more answers
What's larger centimeter or meter?
hoa [83]

Answer:

A meter is 100 times larger then a centimeter

6 0
2 years ago
Electrons in atoms exist in particular energy level. A ___ must be emitted or absorbed to move between energy levels.
svetlana [45]

Answer:

Photon of light

Explanation:

According to Bohr's model of the atom, electrons in atoms are found in specific energy levels. These energy levels are called stationary states, an electrons does not radiate energy when it occupies any of these stationary states.

However, an electron may absorb energy and move from one energy level or stationary state to another. The energy difference between the two energy levels must correspond to the energy of the photon of light absorbed in order to make the transition possible.

Since electrons are generally unstable in excited states, the electron quickly jumps back to ground states and emits the excess energy absorbed. The frequency or wavelength of the emitted photon can now be measured and used to characterize the transition. This is the principle behind many spectrometric and spectrophotometric methods.

8 0
3 years ago
An experiment to measure the enthalpy change for the reaction of aqueous
Komok [63]

Given that, an experiment to measure the enthalpy change for the reaction of aqueous copper(II) sulfate, CuSO4(aq) and zinc, Zn(s) was carried out in a coffee cup calorimeter; the heat of the reaction in the whole system is calculated to be 2218.34 kJ

Heat of reaction (i.e enthalpy of reaction) is the quantity of heat that is required to be added or removed when a chemical reaction is taken place in order to maintain all of the compounds present at the same temperature.

The formula used to calculate the heat of the reaction can be expressed as follows:

Q = mcΔT

where:

  • Q = quantity of heat transfer
  • m = mass
  • c = specific heat of water = 4.18 kJ/g °C (constant)
  • ΔT = change in temparature

From the information given:

  • The initial temperature (T₁) = 25° C
  • The final temperature (T₂) = 91.5° C

∴

The change in temperature i.e. ΔT = T₂ - T₁

ΔT = 91.5° C - 25° C

ΔT = 66.5° C

The number of moles of CuSO₄ = 1.00 mol/dm³ × 50.0 cm³

\mathbf{= (1 \times \dfrac{50}{1000})\ moles}

= 0.05 moles

  • Since the molar mass of CuSO₄ = 159.609 g/mol

Then;

Using the relation:

\mathbf{number \ of \ moles = \dfrac{mass}{molar \ mass}}}

By crossing multiplying;

mass of CuSO₄ = number of moles of CuSO₄ ×  molar mass of CuSO₄

mass of CuSO₄ = 0.05 moles  × 159.609 g/moles

mass of CuSO₄ = 7.9805 grams

∴

Using the formula from above:

Q = mcΔT

Q = 7.9805 g × 4.18 kJ/g °C × 66.5° C

Q = 2218.34 kJ

Therefore, we can conclude that the heat of the reaction is 2218.34 kJ

Learn more about the chemical reaction here:

brainly.com/question/20250226?referrer=searchResults

8 0
2 years ago
In Keynes's liquidity preference framework, as the expected return on bonds increases (holding everything else unchanged), the e
Julli [10]

Answer:

the correct words to fill up the blank spaces are falls and money

Explanation:

.1. the expected return on money falls

.2. causing the demand for money to fall.

3 0
3 years ago
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