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miss Akunina [59]
3 years ago
7

1. According to the fossil record, the first LAND plants were most likely pine trees. moss and ferns. flowering plants. 2. Scien

tists have found fossils of pine cones, seeds, and leaves with veins. More than likely scientists would also find fossilized remains of fish. dinosaurs. mammals 3. Lots of shell fossils and no plant fossils tell us that Earth probably mostly covered with oceans and little dry land. true
Chemistry
2 answers:
Lynna [10]3 years ago
7 0

Answer:

It is true that earth was once covered with oceans and little dry land.

Explanation:

Over the course of around four billion years, the Earth's oceans have lost about a quarter of their original mass. Today the atmosphere is rich in oxygen, which reacts with both hydrogen and deuterium to recreate water, which falls back to the Earth's surface. So the vast bulk of the water on Earth is held in a closed system that prevents the planet from gradually drying out. According to the researchers,  the continents emerged relatively suddenly from an ocean that covered 95 percent of the Earth's surface. The appearance of large masses of dry land would have caused more extreme weather, changes in ocean currents and the emergence of proper seasons. In turn, these environmental changes may have led to rise in atmospheric oxygen that enabled the explosion of new life forms around 500 million years ago.

Law Incorporation [45]3 years ago
3 0

Answer:

Explanation:

`1. Moss and ferns

2.  Mammals

3. True

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Jill then wrote the formulas for all the possible compounds that sodium can form with the other ions. What formulas did she writ
sp2606 [1]

Explanation:

Sodium has atomic number of 11 and its electronic configuration is given by:

[Na]=1s^22s^22p^63s^1

The nearest stable electronic configuration to sodium is of the neon. So, in order to attain stability of noble gas it will loose its single electron.

Na\rightarrow Na^++1e^-

[Na^+]=1s^22s^22p^63s^0

Sodium has single valency that is 1.

Let nbe the valency of the ion 'X'

By criss-cross method, the oxidation state of the ions gets exchanged and they form the subscripts of the other ions. This results in the formation of a neutral compound.

Na_nX_1

So, the formulas for all the possible compounds that sodium can form with the other ions will be:

Na_nX_1

4 0
3 years ago
A student investigated how much solid was dissolved in sea water.
SashulF [63]

Answer:

weighing balance/analytical balance

Graduated cylinder/buret

Explanation:

The mass of the evaporating basin could be measured using a weighing balance or an analytical balance. Both are classified as weighing scales but the analytical balance can measure the mass of objects up to 4 decimal places, thus, providing better accuracy in measurement than ordinary weighing balance that can only measure up to 2 decimal places.

In order to measure 50 cm3 of the sea water, a graduated cylinder or a buret can be used. Both equipment can measure up to the same decimal places and, thus, have virtually the same accuracy.

3 0
3 years ago
Which of these limiting factors is MOST likely to affect low-growing plants in a tropical forest? Group of answer choices air wa
Georgia [21]

Answer:

air, water, sunlight

Explanation:

A limiting factor may be defined as a environmental condition or a resource that can limit the plant growth as well as distribution or the abundance of an organism or its population within the ecosystem. The ability  of any plant species to grow and spread throughout any geographic area is the direct result of the adaption to its biotic  and abiotic components of that region.

Some of the factor that affect the plant growth are : sunlight, air, proper temperature, moisture, nutrients, wind,etc.

The lack of the any one of the above essential component will determine the health of the  plant.

8 0
4 years ago
Octane has a density of 0.703 g/ml. Calculate the mass of CO2(g) produced by burning one
STatiana [176]

The mass of CO₂ gas produced during the combustion of one gallon of octane is 8.21 kg.

The given parameters:

  • <em>Density of the octane, ρ = 0.703 g/ml</em>
  • <em>Volume of octane, v = 3.79 liters</em>

<em />

The mass of the octane burnt is calculated as follows;

m = \rho V\\\\m = 0.703 \ \frac{g}{ml} \times 3.79 \ L \ \frac{1000 \ ml}{L} \\\\m = 2,664.37 \ g

The combustion reaction of octane is given as;

2C_8H_{18} +  \ 25O_2 \ --> \ 16CO_2 \ + \ 18H_2O

From the reaction above:

228.46 g of octane -------------------> 704 g of  CO₂ gas

2,664.37 of octane --------------------> ? of CO₂ gas

= \frac{2,664.37 \times 704}{228.46} \\\\= 8,210.3 \ g\\\\= 8.21 \ kg

Thus, the mass of CO₂ gas produced during the combustion of one gallon of octane is 8.21 kg.

Learn more about combustion of organic compounds here: brainly.com/question/13272422

8 0
3 years ago
What is the volume occupied by 4.20 miles of oxygen gas (O2) at STP
Drupady [299]

Answer: 94.13 L

Explanation: In STP in an ideal gas there is a standard value for both temperature and pressure. At STP,pressure is equal to 1atm and the temperature at 0°C is equal to 273.15K. This problem is an ideal gas so we use PV=nRT where R is a constant R= 0.08205 L.atm/mol.K.

To find volume, derive the equation, it becomes V=nRT/P. Substitute the values. V= 4.20 mol( 0.08205L.atm/mol.K)(273.15K) / 1 atm = 94.13 L. The mole units, atm and K will be cancelled out and L will be the remaining unit which is for volume.

8 0
3 years ago
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