Answer:
0.124% of Cr2O3 in the sample
Explanation:
A mass percent is expressed as 100 times the ratio of the mass of analyte and the mass of the sample. For this problem, the equation is:
Mass Cr2O3(g) / Mass Mineral(g) * 100
To solve this question we must convert the mass of Cr2O3 to grams and then, compute the value in the equation:
Mass Cr2O3 in g:
0.560mg * (1g / 1000mg) = 5.6x10⁻⁴g Cr2O3
Percent of Cr2O3 is:
5.6x10⁻⁴g Cr2O3 / 0.45g * 100
0.124% of Cr2O3 in the samplewhat does the t cell do to your body?
Answer: it's part of the immune system that focuses on specific foreign particles. Rather than generically attack any antigens, T cells circulate until they encounter their specific antigen. As such, T cells play a critical part in immunity to foreign substances !
Explanation:
100 pts HORTICULTURE (HURRY)
The hundredweight is the common way of evaluating crop yield for which of the following crops?
A. wheat
B. soy
C. rice
D. corn
Answer:
Option A and C
Explanation:
Generally yield of wheat and rice crop is measured in terms of hundredweight. It is also known as centum weight or quintal. one quintal is equal to 100 Kg. It is used primarily in United States of America and British reign. In India quintal is used to measure the yield of wheat and rice
Hence, option A and C is the correct answer
Answer:
Option C, Rice
Explanation:
Rice is measured in hundredweight as stated in the lesson, wheat isn't mentioned to be measured by hundredweight.
What important ingredients do you need to create a fertilized egg
Answer:
In the 1970s, Epel and other researchers showed that calcium is the essential factor that sparks development in eggs. As calcium levels rise, metabolic changes occur that cause the egg to divide and form into an embryo.
Explanation:
What type of reaction is
illustrated?
Ca + CuSO4 -> CaSO4 + Cu
A. synthesis
B. decomposition
C. single
replacement
Explain why the following are made of thermosetting plastics.
(a) Saucepan handles
(b) Electric plugs/switches/plug boards
Answer:
a: they're used in saucepan handles 'cause they don't soften when heated and also 'cause they cant be bent easily.
b: thermosetting plastics are bad electricity conductors. they don't get moulded and are also hard and strong.
How is 2Mg+O2= 2MgO balanced?
Answer:
A half-reaction can be written to represent reduction. At the same time the magnesium atoms become ions, the oxygen atoms become –2 anions by gaining one electron each. By combining these two reactions, we have an oxidation reaction and a re- duction reaction, that are perfectly balanced.
Explanation:
Regroup terms.
2Mg+2O=2mgo
Subtract 2Mg2Mg from both sides.
2O=2mgo-2Mg
Factor out the common term 2.
2O=2(mgo-Mg)
Cancel 2 on both sides.
O=mgo−Mg
which electrons of an atom take part in a bond formation
Answer:
The electrons in the outermost electron shell are responsible for forming chemical bonds. These electrons are also known as valence electrons. Chemical bonds are formed when the outermost electron shells are not completely filled and atom needs more (or less) electrons to completely fill the outermost shell.
Explanation:
Calcium hydroxide, Ca(OH)2, is an ionic compound with a solubility product constant, Ksp, of 6.5×10–6. Calculate the solubility of this compound in pure water.
Answer: The solubility of this compound in pure water is 0.012 M
Explanation:
Solubility product is defined as the equilibrium constant in which a solid ionic compound is dissolved to produce its ions in solution. It is represented as [tex]K_{sp}[/tex]
The equation for the ionization of the is given as:
[tex]Ca(OH)_2\rightarrow Ca^{2+}+2OH^-[/tex]
By stoichiometry of the reaction:
1 mole of [tex]Ca(OH)_2[/tex] gives 1 mole of [tex]Ca^{2+}[/tex] and 2 mole of [tex]OH^-[/tex]
When the solubility of [tex]Ca(OH)_2[/tex] is S moles/liter, then the solubility of [tex]Ca^{2+}[/tex] will be S moles\liter and solubility of [tex]OH^-[/tex] will be 2S moles/liter.
[tex]K_{sp}=[Ca^{2+}][OH^{-}]^2[/tex]
[tex]6.5\times 10^{-6}=[S][2S]^2[/tex]
[tex]S=0.012M[/tex]
Thus solubility of this compound in pure water is 0.012 M
8. (07.05 LC)
Which statement is correct about the rate of most chemical reactions? (5 points)
1.It increases when the concentration of reactants decreases.
2.It does not depend on the concentration of reactants.
3.It increases when the temperature increases.
4.It does not depend on the temperature.
Answer: 3.It increases when the temperature increases.
Explanation:
The speed of most chemical reactions increase as if the temperature of those same reactions increase as well. This is because a higher temperature allows for reactants to gain the necessary activation energy needed to react.
Enzymes are another reason. Enzymes are catalysts in reactions which reduce the activation energy needed for a reaction to occur and enzymes work best in certain higher temperatures - not too high - so this also leads to the reaction speed increasing due to temperature increases.
Answer:
It increases when the temperature increases.
Explanation:
I took the test and the other guy is right ;)
How many molecules of nitrogen gas are found in 0.045 L of nitrogen gas at STP
Answer:
1.2 × 10²¹ molecules
Explanation:
Step 1: Given data
Volume of nitrogen gas (V): 0.045 LConditions: Standard temperature (273.15 K) and standard pressure (1 atm)Step 2: Calculate the number of moles corresponding to 0.045 L of nitrogen gas at STP
At STP, 1 mole of nitrogen gas occupies 22.4 L.
0.045 L × 1 mol/22.4 L = 2.0 × 10⁻³ mol
Step 3: Calculate the number of molecules in 2.0 × 10⁻³ moles of nitrogen
We will use Avogadro's number: there are 6.02 × 10²³ molecules in 1 mole of molecules of nitrogen gas.
2.0 × 10⁻³ mol × 6.02 × 10²³ molecules/1 mol = 1.2 × 10²¹ molecules
True or False: If bubbles are produced when two reactants are mixed, a chemical reaction has occurred.
Answer:
True
Explanation:
Because yes
Answer:
true because that is a reactant or the chemical
Explanation:
Please Help! My question is attached below.
Answer:
C?
Explanation:
what would be the effect of bringing a negatively charged metal ball near an iron bar
When the negatively charged metal ball comes in contact with the iron bar, the positive charges of the bar aligns near to the negative charges and they electrostatically attracts results in a static electricity.
What is static electricity?When a negatively charged body is comes in contact with an conductor or an insulator, the random charges gets polarized, where the positive charges of the second object align with the negative charges and there occurs a flow of electron from the negatively charged object. This is called static electricity.
A metal in its neutral state contains a sea of positive ions and free electrons. Here, the when the negatively charged metal ball comes near the iron bar, the iron bar gets polarized.
The positive charges of the iron bar gets polarized near the negative charge of the ball and there occurs an electrostatic force of attraction. Electrons from the negative charged ball tends to flow to the conductive iron bar and leads to a static electricity.
To find more on static electricity, refer here:
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At terminal velocity, which two forces are balanced? *
gravity and air resistance
gravity and magnetism
O magnetism and air resistance
O friction and air resistance
Answer:
friction and air resistance
at terminal velocity, the weight of the object due to gravity is balanced by the frictional forces, and the resultant force is zero.
Can someone help me answer these chemistry problems?
1. How many moles of helium are required to fill a 5.10 L balloon to a pressure of 1.1 atm at 22 degrees C? Show your work to receive full credit.
2. If there are 4.00 moles of a gas at a pressure of 5.60 atm and a volume of 12.0 liters, what is the temperature? Show your work to receive full credit.
3. If I contain 3 moles of gas in a container with a volume of 60 liters and at a temperature of 400 K, what is the pressure inside the container? Show your work to receive full credit.
4. You are given a 3.00 mol sample of krypton with a volume of 7.00 L. The temperature is held at 300. K. What is the pressure of the krypton sample? Show your work to receive full credit.
5. The air at the top of Mount Everest has pressures of 201.0 torr N2, 50.0 torr O2, 2.0 torr Ar, and 0.5 torr CO2. What is the total air pressure at the top of the highest peak in the world? Show all work to receive full credit.
6. A mixture of 1.20 mols He, 2.40 mols Ne, 4.80 mols Kr, and 0.60 mols Ar has a total pressure of 600.0 mm Hg. What is the partial pressure of the Kr? Show all work to receive full credit.
Answer:
Q.1
To calculate moles of helium (n)=?
given
p=1.1 Atm
V=5.10 L
T =22°C
R =8.314 (universal gas constant)
Now use,
PV = nRT
1.1×5.10 =n×8.314×22
n= 5.61÷182.9
n= 0.030 moles
Use the same method to solve further questions!
To try and stimulate the correct distance, how close would you put the animal
representing the electron?
its out of
Select one
Here's link to the answer:
bit.[tex]^{}[/tex]ly/3a8Nt8n
Answer: out in the parking lot
Explanation:
If the velocity of the spacecraft is 250 m/s and the asteroid is pushed back –25 m/s, what is the mass of the asteroid? Assume there is no net force on the system. 100 kg 6,250 kg 10,000 kg 6,250,000 kg
Answer:10,000 kg
Explanation:I went on my calculator and did 1,000 × 250 ÷ 25 or -25 to get 10,000 or -10,000 ;)
You have been shipwrecked on a deserted island with no running water/fresh water, you have your clothes and a plastic bag containing your phone out of
charge and some sunscreen) How are you going to survive and escape?
Answer:
i have no clue
Explanation:
how conditions on Earth would be different if its axis of rotation were vertical instead of tilted.
Answer:
there would be different times because the sun and moon are in different places and one side would be sunny for a long time
Explanation:
A wave traveling through air meets an object and bounced off its flat surface
at a new angle. Which statement best describes what has happened to the
wave?
A. The object reflected the wave.
B. The object caused the wave to refract.
C. The object absorbed the wave's energy.
D. The object had a slit in its surface that diffracted the wave.
SUBMIT
When a wave moves through the air and comes into contact with an object, it hits its flat surface from a new angle, causing the wave to refract.
When a wave passes through one material and moves through another, how does its direction change?When waves cross the boundary between two different materials, their speed changes. For example, light waves refract when they pass through glass to air. Refraction is the effect that causes them to change direction as a result. When water waves move from deep water to shallow water (or the other way around), they refract light.
When a wave traveling through the air comes into contact with an object and bounces off its flat surface, what happens?
When waves bounce back from a surface they can't pass through, this is called reflection. When waves enter a new medium at an angle and begin traveling at a different speed, refraction occurs. Diffraction happens when waves spread out as they travel around impediments or through openings in obstructions.
To know more about wave visit :-
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a 20.0 mL solution of HCl with a pH if 1.500 is diluted by the addition of 80.0 additional mL of water, so that the total solution volume is 100.0 mL. What is the new pH of the solution after the dilution?
a.) 7.000
b.) 2.199
c.) 3.320
d.) 12.599
answer is a
Explanation:
why is the volume of hydrogen is doubled the volume of oxygen in electrolysis of water?
Answer:
The volume of the hydrogen produced is always twice the volume of the oxygen produced, because water contains two atoms of hydrogen for each atom of oxygen.
Which of the following would not be studied within the topic of stoichiometry?
Answer:
The amount of energy required to break the ionic bonds in CaF2.
Can someone help me please I am doing a test!!.
Your lips are more sensitive to touch than your forehead. What is different about the touch receptive fields in the lips compared to the forehead?
(Mark the one best answer.)
A There are more touch receptive fields in the lips.
B The touch receptive fields are bigger in the lips.
C The touch receptive fields are more sensitive in the lips.
D The touch receptive fields are used more often in the lips
Answer:
c i think
Explanation:
Please help me, I really don't want to fail but I don't know how to do this
Answer:
A)
4, 7, 4, 6
B)
12 moles
Explanation:
[tex] NH_{3}(g) + O_{2}(g) \: → NO_{2} + H_{2}O(g)[/tex]
__↑______↑
8.00 mol | 14.00 mol
________________
[tex] NH_{3}(g) + O_{2}(g) \: → NO_{2} + H_{2}O(g)[/tex]
You can turn this into a system of variables which are solvable.
To do this, create variables for the coefficients of each compound in the reaction respectively.
[tex] a(NH_{3}(g)) + b(O_{2}(g)) → \\c(NO_{2}) + d(H_{2}O(g))[/tex]
Because to be balanced, the count of atoms in each element of the compound correspond to the coefficient of the variable in that compound so that the count of the left (reactant) side is set equal to the right (product) side.
a corresponds to the coefficient of the first compound, b corresponds to the coefficient of the second compound, c corresponds to the coefficient of the third compound, and d corresponds to the coefficient of the fourth compound.
(Reactant = Product)
Reactant: 1a [N] Product: 1c.
Reactant: 3a [H] Product: 2d.
Reactant: 2b [O] Product: 2c + 1d.
Thus the system is:
1a = 1c
3a = 2d
2b = 2c + 1d.
Then just use the substitution methods to solve.
Use the above steps to balance the reaction for the combustion of methane.
____CH4 + ___O2→ ____CO2 + ___H2O
Answer:
__1__CH4 + __2_O2→ __1__CO2 + _2__H2O
True/False: A virus could have a mutation that makes it more transmissible (higher
chance of spreading).
Answer True
Explanation:
I NEED HELP ASAP alligator
turtle
raccoon +
According to the food web above,
which of the following would be an
example of a predator-prey
relationship?
bass
egret mountain lion
snail
sunfish
deer
algae
shrub
A snail and sunfish
Balligator and raccoon
Cinsect and deer
D mountain lion and alligator
insect
The reason Senators are in office for 6 years is....( No links pls or I’m reporting you :)
1) To separate Senators from the whims of the
general public.
2) to save money in elections
3) Because Senators are required to be older
than representatives
What happens to the molecules within a gas when the gas condenses?
A.
They gain energy.
B.
They lose energy.
C.
They drift apart.
D.
They move faster.
Answer:
B
Explanation:
They lose energy and slow down and move closer to other gas molecules and the molecules collect together to form a liquid
Answer:
B. They lose energy.
Explanation:
took the test, can confirm it's b ヾ(•ω•`)o