Answer:
57.68
Explanation:
Last digit is 5 so we round of 7 to 8
Which statements about freshwater sources are true? Check all that apply.
O Only about 3 percent of Earth's water ís fresh water.
O Most of the fresh water on Earth is groundwater.
O About 75 percent of the fresh water on Earth is frozen in ice sheets.
O The largest source of usable fresh water is groundwater.
O More fresh water is in the atmosphere than in rivers and lakes.
Answer:
Explanation:
1 is true
2 is false
3 is true
4 is true
5 is false
That is what I got from researching.
Only about 3% of the water in the Earth is fresh water and about 75 % of the fresh water on Earth is frozen in ice sheets.
• The most vital element present on the Earth is water. All the living beings are dependent on it.
• Water is present in the majority of the Earth, however, of this only 3% of the water is freshwater, the rest is saline and undrinkable.
• Of this 3%, the 75 percent of the freshwater is present in the form of ice and glaciers in the polar region.
• The remaining 24 percent is the groundwater and the rest 1 percent includes the waters of rivers, lakes, and ponds.
• The prime source of usable freshwater is present in the trapped form in the ice and glaciers.
Thus, the correct statements are 1st and 3rd.
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How would you do this?
The empirical formula : C₁₀H₂₀O
Further explanationGiven
Combustion of menthol
Required
The empirical formula
Solution
Mass of CO₂ produced : 0.449 g
mass C = 12/44 x 0.449 = 0.122
Mass water produced : 0.1840 g
Mass H = 2.1/18 x 0.1840 = 0.02
Mass O in menthol :
=mass sample - (mass C+mass H)
= 0.1595 - (0.122+0.02)
= 0.0175
Mol ratio C : H : O in sample :
= 0.122/12 : 0.02/1 : 0.0175/16
= 0.01 : 0.02 : 0.001
= 10 : 20 : 1
Identify the following as a chemical (C) or physical property (P):
1. blue color ______
2. melting point ______
3. density ______
4. reacts with water ______
5. flammability (burns) ______
6. solubility (dissolves) ______
7. boiling point ______
8. luster ______
Answer: 1. Phys 2. Phys 3. Phys 4. Chem 5. Chem 6. Phys 7. Phys 8. Phys
Explanation:
According to the concept of physical and chemical property ,reaction with water and flammability are chemical properties while rest are physical properties.
What are chemical properties?These properties are defined as those properties which become evident during or after a chemical reaction after the identity of the substance is changed during chemical reaction.
These properties cannot be determined externally just by viewing the substance ,these change immensely after a substance undergoes a chemical change.These are used for identification of unknown substances and for building up chemical classifications.
The major chemical properties are flammability,toxicity,reactivity,acidity and heat of combustion.For a chemical property to be apparent , it is necessary that the structure of the substance is altered.
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xg 4Na + 15g 02 → 70g 2Na20
Answer: 43.125g
Explanation:4Na+ O2=2Na2O
Molar mass: 23. 32. 62. React.mass: 92.
What kind of energy can be transferred?
Help quick please.
Answer:
Any kind, as long as there is an action.
Answer:
Energy can be transferred from one form to another like kinetic energy to potential energy, light energy to heat energy, kinetic energy to electrical energy, light energy to chemical energy .etc ...
Explanation:
brainest please
A student states, "When the alcohol sample was at a temperature of 500 K, all the particles were moving faster than any of the particles were moving at 400 K." Do you agree or disagree with this student’s statement? Justify your answer
Answer: i rlly dont know srry
Explanation:
When using the process of evaporation to separate a mixture, what is left behind
in the evaporating dish?
Answer:
When a solution is heated, the solvent evaporates, leaving behind the dissolved solids as residue. When a solution containing dissolved solutes is heated, the solvent will evaporate. Only the solute will remain in the evaporating dish.
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When using the process of evaporation to separate a mixture, solute is left behind in the evaporating dish
What is evaporation?
Evaporation is a sort of vaporization that occurs on a liquid's surface when it transitions from a liquid to a gas.
Evaporation is a separation technique that can be used to separate components of a combination including a decomposed solid in a liquid. The liquid gets evaporated, which means it is converted from a liquid to a gas. This frequently necessitates the use of heat. The solid will be all that remains after the liquid has entirely evaporated.
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I don’t know this question please help
Answer: A. is elliptical
B. IS inrregulur C. spiral
Explanation: this should be it
Calculate the pH after 0.13 mol NaOH are added to 1.00 L of 0.50M HC2H3O2 and 0.80M NaC2H3O2 buffer solution, Ka= 1.3 x 10^-5. I really need help, I'm struggling with this topic.
Determine how many mL of solution A (acetic acid-indicator solution) must be added to solution B (sodium acetate-indicator solution) to obtain a buffer solution that is equimolar in acetate and acetic acid. Solution A: 10.0 mL 3.0e-4M bromescol green
hoped I helped
What is this equation balanced?
Answer:
2Al + 6HCl —> 3H₂ + 2AlCl₃
Explanation:
From the question given above:
Al + HCl —> H₂ + AlCl₃
The above equation can be balance as illustrated below:
Al + HCl —> H₂ + AlCl₃
We have 1 atom of Cl on the left side and 3 atoms on the right side. It can be balance by putting 6 in front of HCl and 2 in front of AlCl₃ as shown below:
Al + 6HCl —> H₂ + 2AlCl₃
We have 6 atoms of H on the left side and 2 atoms on the right side. It can be balance by 3 in front of H₂ as shown below:
Al + 6HCl —> 3H₂ + 2AlCl₃
We have 1 atom of Al on the left side and 2 atoms on the right side. It can be balance by putting 2 in front of Al as shown below:
2Al + 6HCl —> 3H₂ + 2AlCl₃
Thus, the equation is balanced.
How many moles of nitrogen are in a 14.57 gram sample of nitrogen?
Answer:
[tex]\boxed {\boxed {\sf About \ 1.040 \ moles \ of \ nitrogen }}[/tex]
Explanation:
To convert from grams to moles, we must use the molar mass. This can be found on the Periodic Table. We have a sample of nitrogen, so look for N on the table.
Nitrogen (N): 14.007 g/molNow, use this molar mass as a ratio.
[tex]\frac {14.007 \ g \ N }{1 \ mol \ N }[/tex]
Multiply by the number of grams in the sample (14.57)
[tex]14.57 \ g \ N *\frac {14.007 \ g \ N }{1 \ mol \ N }[/tex]
Flip the fraction so the grams of nitrogen will cancel.
[tex]14.57 \ g \ N *\frac {1 \ mol \ N }{14.007 \ g \ N}[/tex]
[tex]14.57 *\frac {1 \ mol \ N }{14.007 }[/tex]
[tex]\frac {14.57 \ mol \ N }{14.007 }[/tex]
[tex]1.04019419 \ mol \ N \\[/tex]
The original measurement of grams had 4 significant figures, so we need to round our answer to the same number of sig figs.
For the number we calculated, that is the thousandth place. The 1 in the ten thousandth place tells us to keep the 0 in the thousandth place.
[tex]1.040 \ mol \ N[/tex]
There are about 1.040 moles of nitrogen in 14.57 grams.
PLEASE HELP ME FILL IN THE BLANKS
Answer:
The order the words go for the blanks
Explanation:
Interia
Rest
Constant
Unbalanced
Balanced
Distance
11. Which elements are least likely to react with other elements? A) metals C) nonmetals B) noble gases D) transition elements
Answer:
I believe the answer is B. Noble gases.
Explanation:
their outer shell is already full of electrons which makes then less reactive.
The process of pumping oxygen-rich blood out of your heart into the rest of your body 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:
its A
Explanation:
Answer:
Pulmonary circulation.
Explanation:
The question is asking you to identify a process. The process is pulmonary circulation. While your blood certainly transports nutrients, water, and waste materials, that answer simply does not match the structure of the question.
The primary food source for many sea animals is:
crayfish
squid
sea grass
plankton
Answer:
plankton
Explanation:
like in spongebob lol but for real I'm a marine biologist I know this is the answer lol
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Which of the following is not a good safety practice in the kitchen?
A
keep cleaning agents in a safe place away from food supplies
B
keep household cleaners and other hazardous chemicals in their original container
C
mix household cleaners to get a stronger cleaning product
D
keep the phone number for the poison control hotline next to the phone
Answer:
C
Explanation:
LIFE LESSON: mixing cleaning products can create toxic chemicals and gas. please do NOT attempt doing anything like that kids.
27/13AL+? ->> 24/11NA+4/2HE
Answer:
hhhsstyi chick to yay to today do y'all
Answer:
¹₀n
Explanation:
The given expression is:
²⁷₁₃Al + ₐᵇT → ²⁴₁₁Na + ⁴₂He
This expression is typical of nuclear reactions. To balance this expression we must conserved the mass number and the atomic number.
The mass number is the superscripts and the atomic number is the subscript;
Now;
conserving mass number:
27 + b = 24 + 4
27 + b = 28
b = 28 - 27 = 1
conserving the atomic number;
13 + a = 11 + 2
13 + a = 13
a = 0
So;
The particle T is a neutron ¹₀n
Calcium
and what
makes bones hard
Uranium has three common isotopes. If the abundance of 234U is 0.0054%, the abundance of 235U is 0.7204% and the abundance of 238U is 99.2742%, what is the average atomic mass of uranium?
Answer:
237.9 amu
Explanation:
Given data:
Abundance of U-234 = 0.0054 %
Abundance of U-235 = 0.7204%
Abundance of U-238 = 99.2742%
Average atomic mass = ?
Solution:
Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) + (abundance of 3rd isotope × its atomic mass / 100
Average atomic mass = (0.0054×234)+(0.7204×235) +(99.2742×238) /100
Average atomic mass = 1.2636+ 169.294+ 23627.2596 / 100
Average atomic mass = 23797.8172/ 100
Average atomic mass = 237.9 amu.
what kind of bond would you find between two alike oxygen atoms
Answer:
Covalent bond
Explanation:
Answer: covalent bonds
BIOdotEDU. A water molecule consists of two atoms of hydrogen linked by covalent bonds to the same atom of oxygen. Atoms of oxygen are electronegative and attract the shared electrons in their covalent bonds.
Explanation:
define the clinical thermometer
Answer:
a small medical thermometer with a short but finely calibrated range, for taking a person's temperature.
Answer:
Thermometer which are used in clinical to measure the temperature of human body is called clinical thermometer.
can you help me on this i neeed help
Answer:
cell,brain,tissue
Explanation:
Name a famous scientists and why they're
famous.
Answer:
Nikola Tesla
Explanation:
He made electricity major, he invented the first AC, and developed AC generation and transmission tech.
A compound contains carbon and hydrogen this compound goes through a combustion reaction such that compound y is produced from the hydrogen atoms in the reactant. What are compounds x and y
Answer:
x is CO2
y is H2O
Explanation:
An organic compound that contains carbon and hydrogen is called a hydrocarbon.
When a hydrocarbon is burnt in air (combustion) only two products are obtained; carbon dioxide and water. The carbon dioxide comes from the carbon component of the molecule while the water comes from the hydrogen component of the molecule.
Therefore, for a hydrocarbon CxHy we obtain; xCO2 and (x + 1)H2O as products.
Answer:
X is carbon dioxide, and Y is water.
Explanation:
I took the test.
5. Describe the effects of photons of light on an electron of the hydrogen atom
Answer:
How do atoms give off light?
Atoms emit light when they are heated or excited at high energy levels. The color of light that is emitted by an atom depends on how much energy the electron releases as it moves down different energy levels. ... It shows the electron moving down energy levels.
Explanation:
Write a complete balanced equation for the following reaction:
magnesium metal reacts with oxygen gas
Explanation:
Given species:
Magnesium metals = Mg
Oxygen gas = O₂
Magnesium metal and oxygen gas are the reactants in this chemical process,
2Mg + O₂ → 2MgO
The product of the reaction is MgO because both oxygen and magnesium are divalent.
This reaction is called a combination reaction where two species combines to form a single compound.
State one part of Dalton’s Atoms Theory?
Answer:
The second part of the Dalton's atoms
theory says all atoms of a given element are identical in mass and properties.
A scientist has 207.45g of H2O in a beaker. How many water molecules are in the beaker?
Answer:
6.94 x 10²⁴molecules
Explanation:
Given parameters:
Mass of water = 207.45g
Unknown:
Number of molecules = ?
Solution:
To solve this problem, we must understand:
1 mole of a substance contains 6.02 x 10²³ molecules
Now, first find the number of moles of water;
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
Molar mass of water = 2(1) + 16 = 18g/mol
Number of moles = [tex]\frac{207.45}{18}[/tex] = 11.53moles
So;
1 mole of a substance contains 6.02 x 10²³ molecules
11.53moles of carbon dioxide will contain 11.53 x 6.02 x 10²³
= 6.94 x 10²⁴molecules
Which of the following happens to a molecule of an object when the object is cooled?
Answer: It loses kinetic energy.