Could somebody answer these questions for me? Thanks!
1. What percentage of the earth is covered by water?
2. What sorts of signals does the brain use to communicate sensations, thoughts and actions?
3. Did dinosaurs and humans ever exist at the same time?
4. What is Darwin's theory of the origin of species?
5. Why does a year consist of 365 days and a day of 24 hours?
Explanation:
1) %70 earth is water and %30 is land.
2)" The single cells in the brain communicatethrough electrical and chemical signals.
3) b'coz earth revolve around the sun in365 days and rotates on its axis in 24 hours. It takes 365 days , because it takes that much time to complete one revolution and it takes 24 hours,because it takes time to complete one rotation as mercury takes 81 earthdays to complete one revolution.
4) Human originated from Adam And Eve.
what causes different colors to appear in the sky?
Answer:
Molecules and small particles in the atmosphere change the direction of light rays, causing them to scatter. Scattering affects the color of light coming from the sky.
Explanation:
A reaction starts with 20.0 grams of lithium hydroxide (LiOH) and produces 31.0 grams of lithium chloride (LiCl), what is the percent yield of lithium chloride (LiCl)? *
LiOH + KCl - LiCl + KOH
A) 64.5%
B) 88.6%
C) 81.5%
D) 92.8%
Answer:
B) 88.6%
Explanation:
Percent yield equals actual yield divided by theoretical yield
actual yield is 31.0g
theoretical yield is 35g
percent yield was 88.57 which rounds up to 88.6%
please help me please
Answer:
b
Explanation:
i read this once and remember,trust me!
Answer:
20 is b and 21 is a.
The endocrine system sends hormones through the blood to control the activities of tissues and organs.
Group of answer choices
a. True
b. False
answer:it is false
explanation: as it is true or false I think you don't need explanation
Sulfuric acid (H2SO4) has a molar mass of 98.1 g/mol. How many oxygen atoms are found in 75.0 g of H2SO4? A. 1.15 × 10^23 B. 1.84 × 10^24 C. 4.61 × 10^23 D. 7.87 × 10^23
Answer:
B
Explanation:
first find the no. Of moles of H2SO4
= 75/98.1
= 0.7645
Next step
In on mole of H2SO4 the no.of oxygen atom is 4.
1 H2SO4 : 4 O
0.7645 : x x= 0.7645x4= 3.0581
next multiply avogadros constant
3.0581 x 6.022× 10^23 =1.84x10^24
Mass present in 1 gram of mole substance is called molar mass. Molar mass is calculated by: dividing the mass of the compound in grams by the number of moles present in the substances.
The correct answer is:
option B. 1.84 × 10²⁴
Given,
The mass of sulfuric acid =75.0 gThe molar mass of sulfuric acid = 98.1 g/mol
1.The moles of sulfuric acid can be calculated by
M = m ÷ n
where M is molar mass, m is mass and n moles.
moles of sulfuric acid = mass ÷ molar mass
= 75 g ÷ 98.1 g/mol
=0.7645 moles
Hence moles of sulfuric acid present is 0.7645 moles.
2. 1 mole of sulfuric acid = 4 oxygen atoms.
Then, 0.7645 moles of sulfuric will contain: 0.7645 × 4 = 3.0581 atoms of oxygen
3. Oxygen atoms present in 75.0 g of H₂SO₄ will be calculated by multiplying it with Avogadro's constant:
= 3.0581 x 6.022× 10²³
= 1.84x10²⁴
Therefore, 1.84 × 10²⁴ oxygen atoms will be found in 75.0 g of H₂SO₄.
To learn more about moles follow the given link:
https://brainly.com/question/20486415
PLZZZ HELP CHEM!!!!!!! Easy points!!!!!
Answer:
H+
Explanation:
Answer:
OH-
Explanation:
An Arrhenius base is any species that increases the concentration of
OH
Calculate the molar mass of ammonium chloride
Answer:
53.491 g/mol
Explanation:
Create the chemical compound and find each individual element's molar mass. Lastly, add them up.
why is the international space station in orbit
Answer:
The ISS provides a location in the relative safety of low Earth orbit to test spacecraft systems that will be required for long-duration missions to the Moon and Mars.
Explanation:
how many number of electrons are in aluminium and nitrogen in their free state?
Answer:
MRCORRECT has answered the question
Explanation:
13 electrons
So... for the element of ALUMINUM, you already know that the atomic number tells you the number of electrons. That means there are 13 electrons in a aluminum atom. you can see there are two electrons in shell one, eight in shell two, and three in shell three.
7 electrons
So... for the element of NITROGEN, you already know that the atomic number tells you the number of electrons. That means there are 7 electrons in a nitrogen atom. Looking at the picture, you can see there are two electrons in shell one and five in shell two.
On May 3, Zirbal Corporation purchased 4,500 shares of its own stock for $36,000 cash. On November 4, Zirbal reissued 800 shares of this treasury stock for $7,200. Prepare the May 3 and November 4 journal entries to record Zirbal's purchase and reissuance of treasury stock.
Answer:
Explanation:
Each share costs $36000/4500
= $8
800 shares will cost 800*8
= $6400
Find attached the journal
What is the charge of an atom's nucleus of an atom has 20 protons, 23 neutrons, and 18 electrons?
Answer:
It would have a charge of +2.
Explanation:
A proton has a charge of +1, an elctron has a charge of -1, and a neutron has a charge of 0. Ignore the neurons since they have a charge of 0. Since there are 20 protons and 18 electrons (20-18), the overall charge of the atom is +2.
During light-dependent reactions, carbon dioxide is converted to glucose.
Group of answer choices
True
False
Answer:The light-independent reactions use the ATP and NADPH from the light-dependent reactions to reduce carbon dioxide and convert the energy to the chemical bond energy in carbohydrates such as glucose.
Explanation:step-by-step
Answer:
FALSE
Explanation:
I just took the test and put true and it was wrong so it's false. Hope this helps and please mark brainliest!
How many grams of H20 will be formed when 32.0 g H2 reacts with 16.0 g
O2? *
2H2 + O2 + 2H2O
9.00 g
16.0 g
18.0 g
32.0g
Answer:
18.0 g
Explanation:
M(H2) = 2.0 g/mol
32.0g * 1 mol/2 g= 16 mol H2
M(O2) = 32 g/mol
16.0 g * 1mol/32 g= 0.5 mol O2
2H2 + O2 ---> 2H2O
from reaction 2 mol 1 mol
given 16 mol 0.5 mol
We see that O2 is a limiting reactant.
2H2 + O2 +-------> 2H2O
from reaction 1 mol 2 mol
given 0.5 mol x mol
x =(0.5*2)/1= 1 mol H2O
M(H2O)= 18 g/mol
18 g/mol* 1 mol = 18 g H2O
Na2O+H2O= 2NaOH how many grams of Na2O are required to produce 1.06*10^2 grams of NaOH
Answer:
77.5 grams of Na2O
Explanation:
Convert grams to mols.
1.06 x 10^2 grams x 1 mol NaOH/39.99
= 2.50 mols NaOH
Find the mole ratio of NaOH and Na2O
1:2
Convert mols NaOH to Na2O mols
2.50 mols NaOH x 1 mol Na2O/2 mols NaOH
= 1.25 mols Na2O
Convert to grams
1.25 mols Na2O x 61.98 grams Na2O/1 mol
= 77.5 grams Na2O required to produce 1.06 x 10^2 grams of NaOH
Is the same reactant always the limiting reactant?
What does the questions “how much?” and “how many?” have in common?
Calculate the molarity of a nitric acid solution if 38 ml of the solution is neutralized by 16 ml of 0.25 M barium hydroxide solution. The balanced equation for the reaction is
Answer:
l
Explanation:
in a titration 20.0 mL of 0.150 M NaOH(aq) Solution exactly neutralize is 24.0 mL of an HCl solution what is the concentration of the HCl solution
Answer:
0.125
Explanation:
i took a test and got it right choosing this answer hopes this help
How many moles of H2 are needed to produce 18 moles NH3 in the reaction below?
N2 + 3 H2 —> 2 NH3
Answer:
27 moles of H₂
Explanation:
Equation of reaction:
N₂ + 3H₂ → 2NH₃
From the equation of reaction,
3 moles of H₂ is required to produce 2 moles of NH₃
3 moles H₂ = 2 moles of NH₃
X moles of H₂ = 18 moles of NH₃
X = (3 * 18) / 2
X = 27 moles of H₂
27 moles of H₂ is required to produce 18 moles of NH₃
Which of the following did Antoine Lavoisier correctly characterize as an element? light silicone dioxide mercury
Answer: mercury
Explanation: I looked up the answer to your question.
Answer:
Mercury
Explanation:
I did this question and I got it right.
what is the correct formula for the compound platinum (vi) flouride?
Answer: PtF6
Explanation: is one of seventeen known binary hexafluorides.
What is the overall reduction potential for the reaction Agt (aq) + Cu(s)——>Ag(s) + Cu2+ (aq)?
-0.46 V
+0.46 V
+0.57 v
+1.14V
Answer:
it should be +0.46 :)
Explanation:
I just took the test and got it right.
Answer:
I think it's +1.14 V, but don't take my word for it..
(02.02 MC)
How is Earth's surface most likely to change in a place that experiences strong sand storms?
Answer:
Mechanical weathering will cause wearing down of rocks.
Explanation:
All the other choices aren't suitable for a dry climate where sand storms occur.
mutations that neither benefit nor harm the organism have (blank) effect on the organisms survival
Answer:
I would say that the mutation has no effect on the organism, as it doesn't help or harm it.
hope this helps :)
Explanation:
Answer:
its a neutral
Explanation:
i did the test
Balance equation: _NO + _H2O = _NH3 + _O2
Answer:
4NO + 6H2O = 4NH3 + 5O2
Explanation:
Think about it this way: there are 4N's 4O's and 12H's and 10O's on both sides that's what makes it balanced
Hope this helps :)
In most mirrors, the virtual image appears to come from behind the mirror. True False
Answer
False
Explanation:
what happens when light is not spread out
Answer:
Spreading out a wave over a larger area just causes the wave strength to weaken, but does not cause gaps to form. Therefore, if you look at photons as waves, spatial gaps never form in light as it travels through free space, no matter how dim it gets.Spreading out a wave over a larger area just causes the wave strength to weaken, but does not cause gaps to form. Therefore, if you look at photons as waves, spatial gaps never form in light as it travels through free space, no matter how dim it gets
Explanation:
In the graph above for the dissociation of a strong acid, why do the bars for H3O+ and A- have the same height as the bar for HA?
Answer:
The concentration of HA is the same as concentration of H3O+ and A- produced.
Explanation:
The dissociation equation is given below:
HA(aq) + H2O (l) —> H3O+(aq) + A-(aq)
From the reaction above, we can see that the acid is monoprotic acid i.e it has only 1 ionisable hydrogen atom.
Now, from the balanced equation, we can see that the acid produced equal concentration of H3O+ and A-.
This account for the reason why the bars for H3O+ and A- have the same height as the bar for HA.
How many senses does the human body have?
O A. 3
B. 5
Answer:
B
Explanation:
sight, hearing, smell, taste and touch
Answer:
Most easiest answer..
There are 5 senses in human body.☺️
