Answer:
B) A control group is used for comparison to other groups.
E) A controlled experiment must have a control group and test group(s).
Explanation:
Answer:
B & E should be the answers
Please answer this question
Answer:
K^2O
Explanation:
I remember a question like this one and I got it right its K^2O
(aka its C)
find the number of molecules in 35.20 g of nitrogen dioxide
Answer:
4.584*10^23 molecules
Explanation:
Find molar mass of nitrogen and oxygen on periodic table.
find molar mass of nitrogen dioxide
use this to find moles of nitrogen dioxide
multiply by avagadros number
g Hydrogen iodide, HI, decomposes at moderate temperatures according to the equation The amount of I2 in the reaction mixture can be determined from the intensity of the violet color of I2; the more intense the color, the more I2 in the reaction vessel. When 3.80 mol HI was placed in a 5.00-L vessel at a certain temperature, the equilibrium mixture was found to contain 0.443 mol I2. What is the value of Kc for the decomposition of HI at this temperature
Answer:
Equilibrium constant, Kc = 0.023
Explanation:
Equation for the decomposition of Hydrogen iodide is given below:
2HI ----> H₂ + I₂
Initially, the number of moles of the reactant and the products are given as follows:
n(HI) = 2 * 3.800 moles = 7.600 moles
nH₂) = 0.000 moles
n(I₂) = 0.000 moles
At equilibrium, the equation becomes: 2HI <----> H₂ + I₂
Number of moles of the reactant and the products are given as follows:
n(HI) = 7.600 - (0.886 + 0.886) moles = 5.828 moles
nH₂) = 2 * 0.443 = 0.886 moles
n(I₂) = 2 * 0.443 = 0.886 moles
Equilibrium constant, Kc = [H₂] [I₂] / [HI]²
Equilibrium constant, Kc = (0.886) * (0.886) / (5.828)²
Equilibrium constant, Kc = 0.023
Help! What is this question I do not understand
Answer:
A 70%
B 92%
C 87%
D 79%
Explanation:
This excercise is about dividing water by liquid.
A cylinder of oxygen (O2) gas at STP has a volume of 2.75 L. How many oxygen molecules does it contain?
Answer:
7.40×10²² molecules.
Explanation:
From the question given above, the following data were obtained:
Volume of oxygen = 2.75 L
Number of molecules of oxygen =?
Next, we shall determine the number of mole of oxygen present. This can be obtained as follow:
22.4 L contains 1 mole of oxygen at STP.
Therefore, 2.75 L will contain = 2.75 / 22.4 = 0.123 mole of oxygen at STP.
Finally, we shall determine the number of molecules of oxygen present. This can be obtained as follow:
From Avogadro's hypothesis:
1 mole of oxygen = 6.02×10²³ molecules
Therefore,
0.123 mole of oxygen = 0.123 × 6.02×10²³
0.123 mole of oxygen = 7.40×10²² molecules.
Thus, the cylinder contains 7.40×10²² molecules of oxygen.
How many sulfur atoms are in 3.7 mol of SO2?
× 10 S atoms
Answer: 22.3 *10^23 S atoms
Explanation:
The type of radioactive particle that can be stopped by a sheet of paper is the
A. alpha particle
B. beta particle
C. gamma ray
D. uranium
Please help me thanks so much
Answer:
a switch
Explanation:
Answer:
a switch is the answer hope it helps
help and will give brainly. PLEASEEEEEEEEEEEEEEE!!!!!
In a single replacement reaction, the chloride ion in NaCl can be replaced
by
a. potassium
b. carbon
c.fluorine
d.neon
Answer:
c. fluorine
Explanation:
A single replacement reaction is defined as the chemical reaction in which a strong molecule replaces the weak molecule from a compound.
In a single replacement reaction, the chloride ion in NaCl can be replaced by fluorine and gives Sodium fluoride as fluorine (F) is stronger than chlorine (Cl) and from other given molecules also. So the single replacement reaction between NaCl and F will be:
NaCl + F2 => NaF + Cl2
Hence, the correct answer is "c. fluorine".
You are given 127 g H2CO3 (Carbonic Acid) and a volume of 800 mL of water, what will the final concentration of your solution be? (The final unit is the Molar (M), but do not include it.) (Round to 3 decimal places.)
Answer:
2.562
Explanation:
First we convert 127 g of H₂CO₃ to moles, using its molar mass:
127 g ÷ 62 g/mol = 2.05 mol H₂CO₃Then we convert 800 mL to L:
800 mL / 1000 = 0.800 LFinally we can calculate the concentration of the solution as molarity:
molarity = moles / litersmolarity = 2.05 mol / 0.800 L = 2.562 MHelp plz now !
Which statement explains why a chemical equation must be balanced?
A. It must show the reactants and products on the correct sides of
the reaction arrow.
B. It must show that the mass of each element involved is conserved
by a chemical reaction.
C. It must show how each chemical formula is written to accurately
represent each substance.
D. It must show that coefficients and subscripts can be used in
chemical formulas.
Answer: B. It must show that the mass of each element involved is conserved by a chemical reaction.
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
The correct statement why a chemical equation must be balanced is It must show that the mass of each element involved is conserved by a chemical reaction.
Answer:
B. It must show that the mass of each element involved is conserved
by a chemical reaction.
Explanation:
a p e x, just took the quiz
Methods of Heat Transfer
Identify the following examples of heat transfer as conduction, convection, or radiation.
1. Touching a metal spoon that is sitting in a pot of boiling water.
Will mark brainliest
Answer:
1
Explanation:
touching a metal spoon ....................water.
As the [h+] in a solution decreases, what happens to the [OH^-]?
А. It increases and the pH increases.
B. It increases and the pH decreases.
C. It increases and the pH stays constant.
D. It decreases and the pH increases.
E. It decreases and the pH decreases.
Explanation:
as the Hydrogen (acid) ion decreases there is a corresponding increase in the Hydroxide (basic) ion.
Hydrogen can be produced according to the following word equation
=zinc +hydrochloric acid =zinc chloride +hydrogen [zn^+2]
Write a complete balanced chemical equation for this chemical reaction?
Answer:
Zn + 2HCl → ZnCl₂ + H₂
Explanation:
First we write the equation using the molecular formulas instead of words:
Zn + HCl → ZnCl₂ + H₂We know zinc chloride is ZnCl₂ as the problem tells us the oxidation state of zinc in the products is +2, and chloride means Cl⁻¹.
Now we proceed to balance the reaction:
There are 2 Cl atoms and 2 H atoms on the right side, so we add a coefficient of 2 to HCl on the left side:
Zn + 2HCl → ZnCl₂ + H₂Can someone please help me!!
Answer:
Less in the top
your well wisher
What is the percent composition of a 16.75 g sample of a compound containing 14.02 g oxygen and 2.73 g hydrogen? Select the correct answer below: 83.7% oxygen, 16.3% hydrogen O 17% oxygen, 13% hydrogen O 68.2% oxygen, 31.8% hydrogen 89.5% oxygen, 10.5% hydrogen
Answer:
83.7% oxygen, 16.3% hydrogen
Explanation:
Mass of compound = 16.75 g
Mass of Oxygen = 14.02 g
Mass of Hydrogen = 2.73 g
Percentage composition = Mass of element / Mass of compound 100%
Percentage composition of Oxygen = 14.02 g / 16.75 g * 100%
Percentage composition of Oxygen = 0.837 * 100 = 83.7%
Percentage composition of Hydrogen = 2.73 g / 16.75 g * 100%
Percentage composition of Hydrogen = 0.163 * 100 = 16.3%
The correct option is;
83.7% oxygen, 16.3% hydrogen
Answer:
83.7% oxygen, 16.3% hydrogen
Explanation:
To determine the percent composition we can divide, our mass by total mass and afterwards, multiply by 100.
(Mass of O / Total mass) . 100 = % O
(Mass of H / Total mass) . 100 = % H
Remember that:
% O + % H = 100
Mass of O / Total mass + Mass of H / Total mass = 1
(14.02 g / 16.75g) . 100 = 83.7 %
(2.73 g /16.75g) . 100 = 16.3 %
Please please help me please please help please please help me please please help please please help me
Answer:
AU9NJ-BLVHV-TCLJS-54YTB
What does Ra Ra Ah Ah Ah Ro Ma Ro Ma Ma Ga Ga O La La mean?
Answer:
They are symbols of elements.
Ra is the symbol of the element Radium
Ah is the symbol of the element Arrhenium
Ma is the symbol of the element Molybdenum
Ga is the symbol of the element Gallium
La is the symbol of the element Lanthanum
Answer:
Ra is the symbol of the element Radium
Ah is the symbol of the element Arrhenium
Ma is the symbol of the element Molybdenum
Ga is the symbol of the element Gallium
La is the symbol of the element Lanthanum
Explanation:
They are elements
Cu + 2AgNO3 → Cu(NO3)2 + 2Ag
If a 40. g sample of Copper is used with an excess of silver nitrate, calculate the theoretical yield of silver. What is the percent yield of the silver, if 120 g was collected?
Answer:
[tex]m_{Ag}=135.8gAg[/tex]
[tex]Y=88.4\%[/tex]
Explanation:
Hello there!
In this case, according to the described chemical reaction, it is possible to compute the theoretical mass of silver as mass via the 1:2 mole ratio of copper to silver and their atomic mass in the periodic table, in order to perform the following stoichiometric setup:
[tex]m_{Ag}=40.gCu*\frac{1molCu}{63.55gCu}*\frac{2molAg}{1molCu}*\frac{107.87gAg}{1molAg}\\\\ m_{Ag}=135.8gAg[/tex]
Next, given the actual yield of 120 g, we compute the percent yield via:
[tex]Y=\frac{120g}{135.8g}*100\%\\\\Y=88.4\%[/tex]
Regards!
hellpppppppp me pleaseeeeeeeee
what element is this?????/
Answer:
Helium
Explanation:
Answer:
the element is helium as it's mass number is 4 and number of electrons is equal to it's atomic no. which is 2
hi, if your looking for extra points (50+) and br ainiest here is ur chance, answer this question correctly plz
Answer:
it should be C. the filtering of ground water. have a good day!
What is the enthalpy change(Q) when 60.0 g of NaOH is dissolved in one litre of water, given that the temperature of the solution increased by 15.8 °C?
Answer:
ΔH = -44.029 KJ/mol
Explanation:
We are told that 60.0 g of NaOH is dissolved in one litre of water.
From conversion, 1 litre = 1000 g
From tables, specific heat capacity of water; c = 4.18 J/g/°C
We are given ΔT = 15.8 °C
Formula for the heat absorbed by the solution is given as;
Q = mcΔT
Where;
Q = Heat gained by the water
m = Mass of the water
c = Specific heat of water
ΔT = change in temperature
Thus;
Q = 1000 × 4.18 × 15.8
Q = 66044 J
The solution absorbed 66044 J and therefore it means that the dissolution of the salt gave off 66044 J.
Thus;
Enthalpy is; ΔH = -66044 J
Now, Mass of NaOH is 60 g.
We know that molar Mass of NaOH is 39.997 g/mol. Thus;
Converting to moles, we have;
n = 60/39.997
n = 1.5 mol
Now, enthalpy when 1.5 moles of NaOH are dissolved in water will be;
ΔH = -66044 J/1.5 moles
ΔH = -44029.33 J/mol
ΔH = -44.029 KJ/mol
Which states have no oil or gas production?
Answer:
Georgia and minessota
Explanation:
they have no production
I NEED HELP!!!!! IM TIMEDDDD! HELP PLZZZZ!!!!
Answer:
a
Explanation:
PLEASE HELP ME PLEASE!!
Answer:
1: f 2: b 3: d 4: e 5:a 6:c
Explanation:
If you know, answer this. If you don’t know this, don’t second guess
Answer:
1 and the element is hydrogen (there is an exception for the octet rule for the element hydrogen) hope this helps
Explanation:
Describe the process of two neutral atoms forming an ionic bond
oops... sorry... I need to delete this response. I was trying to answer a different question,
what makes a substance a good insulator
Answer:
zoo wee mama
Explanation:
The particles that make up an object are held together by bonds. Insulators have strong bonds that hold their particles rigidly in place. This prevents particles from gaining energy and increasing the temperature. Wool, dry air, plastics, and polystyrene foam are all examples of good insulators.
How many moles are in 2.5L of 1.75 M Na2CO3
Answer:
4.4 mol.
Explanation:
Hello!
In this case, since the formula for calculating the molarity is:
[tex]M=n/V[/tex]
Whereas n stands for moles and V for the volume in liters; we can solve for n as shown below when we are given the volume and the molarity:
[tex]n=V*M[/tex]
Thus, we plug in the given data to obtain:
[tex]n=2.5L*1.75mol/L=4.4mol[/tex]
Best regards!
Answer:
4.4 mol.
Explanation:
Have a great day