Answer:
Atomic no. = 8
Mass no. = 16
Period no. = 2
Group no. = 6
Why would early Earth have been toxic for modern day animals? Why were cyanobacteria able to
survive
Answer: The surface of early earth was mostly molten and volcanic. The atmosphere was hot and highly toxic.
Explanation: Photosynthetic organisms were present when earth was primarily anoxic. photosynthetic organisms were present when earth was primarily anoxic. the early forms of photosynthesis did not produce oxygen as a waste product. cyanobacteria carry out anoxic photosynthesis. the early forms of photosynthesis did produce oxygen, but it was not enough to make a difference in the atmosphere. the early forms of photosynthesis were carried out in the water, and there was no way for the oxygen to move into the atmosphere.
1
Early earth have been toxic for modern day animals as at that time atmosphere is oxygen free, and cyanobacteris is able to survive due to symbiosis.
What are cyanobacterias?
Cyanobacteria is a group of microorganisms that are related to bacteria but can perform photosynthesis. They are prokaryotic and are thought to be the earliest form of life on the planet.
Early earth atmosphere may proof toxic for modern day animals because at the earliest time, atmosphere is oxygen free means no oxygen is present in the atmosphere. And in the today scenario we can't imagine life without oxygen.
Cyanobacteria were able to suvive in that early atmosphere through alternative option like symbiosis in which a cell merges with another cell in order to the survival of both cells.
Hence life is toxic at the early time because of the absence of oxygen.
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What is the mass, in grams, of a 12.0cm³ sample of aluminum? The density of aluminum is 2.70g/cm³
Answer:
The answer is
32.4 gExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volumeFrom the question
volume of aluminum = 12 cm³
Density = 2.70 g/cm³
The mass of aluminum is
mass = 2.7 × 12
We have the final answer as
32.4 gHope this helps you
Which statement about melting and boiling points is true? Question 3 options:
A. As you move down group 7A in the periodic table, the melting and boiling points of the elements decrease.
B. As you move up group 8A in the periodic table, the melting and boiling points of the elements increase
. C. Smaller atoms in group 8A require higher boiling points for the molecules to separate from each other than larger atoms in group 8A.
D. Larger atoms in group 8A require higher boiling points for the molecules to separate from each other than smaller atoms in group 8A.
Answer:
B
Explanation:
I believe it is B but I am not entirely sure! don't do this is B doesn't sound or look right to you!
Answer:
Its D
Explanation:
Larger atoms in group 8A require higher boiling points for the molecules to separate from each other than smaller atoms in group 8A.
convert 500 inches to m.
1000mm =1m
1inch = 2.54 cm
10mm=1cm
Answer:
12.7m
Explanation:
FORMULA
for an approximate result, divide the length value by 39.370078
Crystal structures with ions must have ____________.a. a positive chargeb. a negative chargec. electrical neutralityd. a 2+ charge
Answer:
c. electrical neutrality.
Explanation:
A crystalline solid possesses a rigid and long-range order; its atoms, molecules, or ions occupy specific positions. The arrangement of such particles in a crystalline solid is such that the net attractive intermolecular forces are at their maximum.
Ionic crystals, particularly, have two important characteristics:
(1) They are composed of charged species.
(2) Anions and cations are generally quite different in size.
The forces holding the atoms together are electrostatic attractions. Examples of these types of crystals include NaCl, LiF, MgO, CaCO₃.
Since they are composed of anions and cations, in stoichiometric amount, they are to be said electrically neutral.
I need y’all helping me with this question?
5(3x) - 7y2=?, when x = 3 and y= 2
Answer:
This might help u......
What is the noble gas notation For zinc
Answer:
The noble gas notation for zinc would be [Ar]3d^104s^2
Explanation:
I hope this helps you:) let me know if it does make sense, okay?
Calculate the density from the following information: A red block had a mass of 15.7 g. It was placed into a graduated cylinder containing 10.0 mL of water. The volume then rose to 17.2 mL when the block was added.
Answer:
Density should be 8.5
Explanation:
When you subtract 17.2-10.0 for water displacement you get 7.2 which is the volume and you divide it by 15.7 so your equation will be 15.7/7.2 = 8.5
Answer:
4.1
Explanation:
What happens to the sound wave in echolocation?
Olt releases energy
O It is reflected
O It is refracted
O It is absorbed
Answer:
D
Explanation:
What is a key difference between chemical and nuclear reactions?
A. In chemical reactions, new compounds are formed. In nuclear reactions, compounds are destroyed.
B. Chemical reactions involve electron rearrangements. Nuclear reactions involve changes to the nucleus.
C. Chemical reactions involve large changes in energy. Nuclear reactions absorb or release small amounts of energy.
D. In chemical reactions, only alpha radiation is emitted. In nuclear reactions, alpha, beta, and gamma decay may occur.
Answer:
B
Explanation:
Chemical reactions involve electron rearrangements. Nuclear reactions involve changes to the nucleus.
Answer:
B
Explanation:
What is the difference between bulk and particle scale?
Someone please help!!
Answer:
Particle density is the volumetric mass of the solid soil. It differs from bulk density because the volume used does not include pore spaces. Particle density represents the average density of all the minerals composing the soil.
Hope that helps
The Sun-Earth-Moon system can be modeled by using three balls. Which
statement describes a benefit of this model?
O A. It can be easily manipulated to represent changes that occur
slowly.
O B. All parts of the entire solar system can be modeled in the same
way.
O C. The model shows only how moon phases happen.
O D. The actual Sun-Earth-Moon system moves too quickly to be
studied directly.
Answer:
A. it can be easily manipulated to represent changes that occur slowly.
The data were collected over five spring seasons. What is the difference between the number of frogs in the pond when the rainfall was 5 cm and when the rainfall was 20 cm?
Please help
Answer: they like deep water
Explanation: they do
___KClO3--->___KCl+___O2 I need help bro.
A science student wants to use distillation to separate a mixture of two
substances in the liquid state. For the student to be successful, which property
should be significantly different between the two liquids?
h-
ies
h-
Freezing point
Ability to dissolve a solid substance, such as table sugar
1
Ability to react with oxygen
O Boiling point
et
< Previous
Next
Answer:
Boiling point
Explanation:
Distillation is one of the most widely used separation technique in chemistry. It is used to separate a mixture of liquid substances with different boiling point. Hence, the basis of the separation is BOILING POINT DIFFERENCE.
In the procedure, the liquid substances are heated until they turn gaseous, which they do at different times considering their different boiling points. The separated components are then converted back to liquid states in a process called CONDENSATION.
If 2a=3b and a=6 then b=
then b is 4
2a=3b since a=6
2x6=3b
12=3b
b=12/3
b=4
Answer:
b=4
Explanation:
2a=3b
2a=2*6
2*6=12
2a=12
12=3b
12/3=4
b=4
which part of a plant conducts food and water to different part of it?
Answer:
stem is the correct answer
Explanation:
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What is the best way to represent the number 1,550,000
Answer:
You can represent as a exponent. That will be the best way.
Explanation:
a pencil is 7 in Long what is its length in centimeters
look the following picture i think that will help you too find out answer
what type of battery still uses lead?
Answer:
Starter batteries
Explanation:
explain why the planet Venus rotates the opposite way?
Answer:
The reason why it rotates the opposite way is due to an asteroid collision forcing the planet to spin backwards and is also the reason why a day on Venus is longer then a year on Venus
Electronic configuration of 11N
Answer:
The Electronic configuration of 11N is
[Ne]3s1
- At sea level, water boils at 100°C. This is an example of an)
a chemical property.
c. physical property.
b. extensive property.
d. chemical change.
Answer:
d
Explanation:
The measurement of boiling point is a physical property it involves only physical changes and not any chemical change. Hence, option c is correct.
What is physical properties?Physical properties of a substance include properties such as boiling point, melting point, density, mass, solubility etc. These are all characterised with a change in physical state of the substance and not any chemical reactions.
Boiling point of a substance is the temperature at which the substance converts from its liquid state to vapor state where the vapor pressure of the gas phase above the liquid is equal to the atmospheric pressure.
Boiling of a substance does not involve any making or breaking of chemical bonds and not producing a new compound. Therefore, boiling point is a physical property.
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Which of these outcomes is conclusive evidence that mixing sugar in water is a physical change?
OA. There is no change in color.
OB. There is no precipitate formed.
OC. There is no gas given off.
OD. There is no molecular change,
Explanation:
Physical change can observe by physical appearance
OA = No change in color
other choices are chemistry change
Explain how you would test the presence of oxygen and hydrogen gases.
You are throwing a pizza party for 15 people and figure that each person will eat 4 slices. You call the pizza place and learn that each pizza will cost you $14.75 and it will be cut into 12 slices. How much is the pizza for this party going to cost you? Give the answer to the nearest cent.
Answer:
15 people x 4 slices so you’ll need 60 pieces
60/12(the amount of slices per pizza) =5
You need 5 pizzas. $14.78 x 5 = 73.90.
Explanation:
the answer is that one 73.90 is rounded nearest cent : ) took me a while to get it
Answer:
the cost of pizza for 15 people is $73.9
Explanation:
a pizza party for 15 and each person will eat 4 slices.
meaning the 15 people will eat 4 x 15 = 60 slices
Since each pizza will cost you $14.78 and will be cut into 12 slices.
`1 pizza = 12 slices = $ 14.78
60 slices = (14.78 x 60) / 12 = 886.8 /12 = $73.9the cost of pizza for 15 people is $73.9
Constants (“controlled variables”) and a control are easily confused by students! How would you explain the difference between the two words?
Answer:
Please find the explained difference below
Explanation:
In a scientific experiment, the CONTROLLED VARIABLE, also known as CONSTANT, is the the variable that is kept unchanged by the experimenter throughout the course of the experiment. The constants are not part of the actual experiment but altering them can influence its outcome.
A control group is one of the two groups in an experiment (the other being experimental group) that doesn't receive the variable being manipulated (independent variable). The control group is the same as the experimental group except that the independent variable is unchanged in the control group. It is used to make a comparison with the experimental group.
For example, in an experiment to test the effect of sunlight on plant growth. Some plants were exposed to sunlight while some were placed in the dark. The CONTROL group of this experiment are the plants placed in the dark (no light). They didn't receive any treatment.
The constants of this experiment can be same amount of water, same type of plants used etc. This is done in order not to affect the outcome of the experiment.
What is it known as
Answer:
Some of the most incredible discoveries in science were made because the data looked wrong! Once you have the data, you may need to perform a mathematical analysis to support or refute your hypothesis. Conclusion Conclude whether to accept or reject your hypothesis. There is no right or wrong outcome to an experiment, so either result is fine.
how is matter and energy conserved when liquid is frozen
Answer:
The big energy change when water freezes is in the potential energy of interactions between the water molecules.
Explanation:
I am not to sure if this is correct, but I hope it helps in some way.