Answer:
Because we are not perfect
Explanation:
This day is added to the calendar as a corrective measure, because the Earth does not orbit the sun in precisely 365 days.
How can the law of conservation of
mass for a chemical reaction be expressed?
Answer:
The law of conservation of mass states that mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations. According to the law of conservation of mass, the mass of the products in a chemical reaction must equal the mass of the reactants.
Explanation:
How does the concept of conservation of mass apply to chemical reactions? the reactants and products have exactly the same atoms. the reactants and products have exactly the same molecules. the change in the amount of matter is equal to the change in energy.
can someone help me with my qustions?
2. How are UVC rays different from UVA and UVB rays?
a. UVC rays are deflected by earth's atmosphere; UVA and UVB rays aren't
b. UVC rays can penetrate all the layers of your skin; UVA and UVB rays don't
c. UVC rays contain very little energy; UVA and UVB rays are very powerful
d. Sunblock can protect you against UVC rays, but not UVA and UVB rays
Answer: A.. for sure
Explanation:
Please actually help me.
Thank you!
Answer:
The answer is Helium.
Explanation:
Scandium's atomic number is 21.
Sulfur's atomic number is 16
Lithium's atomic number is 3
Helium's atomic number is 2.
Therefore, the answer is Helium.
How many elements, compounds and atoms are in CH3COOH
The movement of blood from your lungs to your heart is ______.
A. picks up nutrients, water, and waste materials
B. pulmonary circulation
C. the lungs, where it picks up oxygen again
D. capillaries
E. 5
F. systemic circulation
Answer:
B. Pulmonary Circulation
Explanation:
Pulmonary circulation moves blood between the heart and the lungs. It transports deoxygenated blood to the lungs to absorb oxygen and release carbon dioxide. The oxygenated blood then flows back to the heart.
How many carbon atoms are in 2C7H5N3O6
Answer:
14
Explanation:
If 2.5 grams of calcium bromide reacted with excess lithium oxide, how many grams of bromide product would be formed?
Answer: 2.17 g of bromide product would be formed
Explanation:
The reaction of calcium bromide with lithium oxide will be:
[tex]CaBr_2+Li_2O\rightarrow 2LiBr+CaO[/tex]
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of calcium bromide}=\frac{2.5g}{199.9g/mol}=0.0125moles[/tex]
As lithium oxide is in excess, calcium bromide is the limiting reagent.
According to stoichiometry :
1 mole of [tex]CaBr_2[/tex] produce = 2 moles of [tex]LiBr[/tex]
Thus 0.0125 moles of [tex]CaBr_2[/tex] will require=[tex]\frac{2}{1}\times 0.0125=0.025moles[/tex] of [tex]NH_3[/tex]
Mass of [tex]LiBr=moles\times {\text {Molar mass}}=0.025moles\times 86.8g/mol=2.17g[/tex]
Thus 2.17 g of bromide product would be formed
Which of the following is the best hypothesis?
*
A. I think the plants given acid will grow taller
B. The plants given acid will be smaller than the plants given only water
C.The plants given water will be better
D.I believe the plants given acid will be smaller
Answer:
b
Explanation:
i think it is b
All of the following rivers are labeled on the map above except the __________ River.
A. Danube
B. Volga
C. Lena
D. Ob
Given the following reaction, how many molecules of H2O will be formed from 200.0g of NaOH?
2 NaOH + H2SO4 -> 2 H2O + Na2SO4
Answer:
30.11×10²³ molecules
Explanation:
Given data:
Mass of NaOH = 200.0 g
Number of molecules of water formed = ?
Solution:
Chemical equation:
2NaOH + H₂SO₄ → 2H₂O + Na₂SO₄
Number of moles of NaOH:
Number of moles = mass/molar mass
Number of moles = 200 g/ 40 g/mol
Number of moles = 5 mol
Now we will compare the moles of NaOH and H₂O.
NaOH : H₂O
2 : 2
5 : 5
Number of molecules of water:
1 mole contain 6.022×10²³ molecules
5 mol × 6.022×10²³ molecules / 1mol
30.11×10²³ molecules
In a population of wheat,
variation in the height of
the wheat decreases
over time so that short
wheat plants survive
more than other heights.
Explain in a short sentence how you can tell if a reaction is a single replacement
reaction.
Explanation:
The reaction can be said to be a single replacement reaction if one substance in a chemical reaction is replacing another one.
For example:
A + BC → AC + B
In such reactions there is a replacement of a metallic ion in solution by a metal atom higher in the activity series than the metal in solution.
The relative positions of the two elements in the activity series provides the driving force for a single replacement reaction. If one element that is to replace another in a compound is more active, the reaction will occur. If it is less reactive, there will be no reaction.
How is carbon(C)-14 is different from carbon(C)-12?
Explanation:
Carbon-12 and carbon-14 are two isotopes of the element carbon. The difference between carbon-12 and carbon-14 is the number of neutrons in each of their atoms. Atoms of both isotopes of carbon contain 6 protons. Atoms of carbon-12 have 6 neutrons, while atoms of carbon-14 contain 8 neutrons.
Which type of climate does Florida have due to its latitude?
After two alpha decays, Carbon-14 will become?
Answer:
Becomes Nitrogen-14
Explanation:
Using the information make a graph.
Convert 4.5 x 10-3 to standard Notation
Posted today at 6:30 am
1
=
Answer:
0.0045
Explanation:
Scientific notation is the way to express the large value in short form.
The number in scientific notation have two parts.
The digits (decimal point will place after first digit)
× 10 ( the power which put the decimal point where it should be)
for example 4.5×10⁻³
In standard notation
4.5 / 10³
0.0045
The expanded notation is standard notation of writing the numerical values which is normal way. The numbers are written as they are, without the power of 10.
An equation that shows only the chemical formulas without
anything to indicate relative amounts is called a ______.
Answer: skeleton equation
Explanation:
If something is up higher it will have ________________ potential energy.
the same
more
less
Answer:
More
Explanation:
what water has 97% of water
Answer:
ocean
Explanation:
because its easy
Which kind of worm has a closed circulatory system?
a planarian
a fluke
a pinworm
an earthworm
An earthworm has a closed circulatory system.
The earthworm has a closed circulatory system. An earthworm circulates blood exclusively through vessels. There are three main vessels that supply the blood to organs within the earthworm.
As important as they are alive for distributing nutrients and organisms and decomposing matter, worms are also very important in the food chain. They provide a crucial protein-rich source of food for other important species like birds, hedgehogs and frogs.
They may live up to eight years, though one to two is more likely. Full size for an earthworm varies among species, ranging from less than half an inch long to nearly 10 feet.
Learn more about earthworm here:- https://brainly.com/question/13938105
#SPJ1
which is more reactive oxygen or hydrogen? explain why?
Answer:
Explanation:
Which is more reactive hydrogen or oxygen?
Hydrogen is not particularly reactive. For example, just mixing hydrogen and oxygen gas will not cause a reaction at room temperature, but many metal elements oxidize at least on the surface in air. ... It is combustible because oxygen wants electrons and takes them from hydrogen to form water.
Subscripts in a molecular formula indicate how many of each type of ____ can be found
Answer:
Atoms
Explanation:
The molecular formula uses chemical symbols to indicate the types of atoms followed by subscripts to show the number of atoms of each type in the molecule. :)
How many moles of Ca3N2 will be produced if you react 6.3 moles of Calcium with an excess (more than you need) of Nitrogen?
3Ca + N2→ Ca3N2
a) 18.9 moles of Ca3N2
b) 6.3 moles of Ca3N2
c) 2.1 moles of Ca3N2
Answer:
C
Explanation:
For every mol of Ca3N2 produced, you will need 3 mols of Ca
So the answer can be set up using a proportion.
3/1 = 6.3 / x Cross multiply
3x = 6.3 *1 Divide by 3
3x/3 = 6.3/3
x = 2.1
The answer is C
2.1 moles of Ca3N2 will be produced if you react 6.3 moles of Calcium with an excess nitrogen. Details about stoichiometry can he be found below.
How to calculate number of moles?The number of moles of a compound can be calculated as follows:
The chemical reaction between calcium and nitrogen is given as follows:
3Ca + N2→ Ca3N2
Based on the above reaction, 3 moles of calcium forms 1 mole of Ca3N2
Hence, 6.3 moles of calcium will produce 6.3/3
= 2.1 moles of Ca3N2
Therefore, 2.1 moles of Ca3N2 will be produced if you react 6.3 moles of calcium with an excess nitrogen.
Learn more about stoichiometry at: https://brainly.com/question/9743981
#SPJ2
100 pts
HELP!!!!!!!!
Between steps 2 and 3, the chemical energy in the coal is converted to
electrical energy
mechanical energy
transitional energy
heat energy
Answer:
It Is Transitional Energy.
Explanation: I Took The Quiz And Got It Wrong. It Showed That Transitional Energy Was The Correct Answer.
Answer:
heat energy
Explanation:
15 POINTS!!
In the South Texas Plains, the Rio Grande River flows along the southern border of the state. The Rio Grande shapes the region through the processes of weathering, erosion, and deposition. Which of the following is an example of the river forming a depositional feature?
A.
As the water's speed decreases along the inside edge of a curve, sediment is laid down to form a point bar.
B.
As the water flows along the outside edge of a curve, it removes rock and soil from the river bank.
C.
As the water's speed increases, it scours deep grooves in the muddy river bottom.
D.
all of these
Answer:
A) As the waters speed decreases along the inside edge of a curve, sediment is laid down to form a point bar
Explanation:
Depositional landforms are the visible evidence of processes that have deposited sediments or rocks after they were transported by flowing ice or water, wind or gravity.
how many atoms of carbon or one mole of glucose
Answer:
6 carbon atoms
Explanation:
For instance, we can say that one molecule of glucose has 6 carbon atoms, or we can say, equivalently, that one mole of glucose has 6 moles of carbon atoms
Which material has carbon atoms interspersed with iron atoms in its molecular structure?
0 hematite
0malachite
0 bauxite
0 steel
Answer:
steel should be correct
Which of these substances has a definite volume but not a definite
shape?
A. paper
B. grass
C. juice
D. water vapor
explain with example the combination and decomposition reaction.
Answer:
Decomposition reactions require an input of some form of energy. For example, under the influence of an electric field, water breaks down to give hydrogen and oxygen. In the presence of sunlight, hydrogen peroxide decomposes into oxygen and water.