The first step of the scientific method is
A make a conclusion
B make observations
C state the problem
D form a hypothesis
E run an experiment
Answer:
B. Make observation
Explanation:
Know the steps and you will see all else comes afterward.
- Hope that helps! Please let me know if you need further explanation.
Covalent bonds tend to form between
Answer:nonmetals
Explanation:
Elements with high electronegativities have a stronger tendency to attract electrons than elements with lower electronegativities.
What volume of oxygen gas at 20°C and 0.919 atm is
consumed in the production of 5.00 g of iron(III) oxide from
metallic iron?
4Fe(s) + 302(g) → 2Fe2O3 (9)
LO2
Answer:
Volume of oxygen gas is 78.47L
Explanation:
Data;
Temperature (T) = 20°C = (20 + 273.15)K = 293.15K
Pressure (P) = 0.919atm
Mass (m) = 5g
Volume (v) = ?
Equation of reaction;
4Fe + 3O₂ → 2Fe₂O₃
From the equation of reaction, the number of moles of oxygen is 3.
To find the volume of oxygen produced, we'll have to use ideal gas equation
PV = nRT
P = pressure
V = volume
n = number of moles
R = ideal gas constant = 0.082J/mol.K
T = temperature of the ideal gas
PV = nRT
V = nRT/ P
V = (3 × 0.082 × 293.15) / 0.919
V = 72.1149 / 0.919
V = 78.47L
Volume of the gas is 78.47L
What mass of water will be collected if 20.0
grams of hydrogen are consumed
2H2+O2--->2H2O
358g
179g
44.7g
Or 89.4g
Answer: 179 of [tex]H_2O[/tex] will be produced.
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} H_2=\frac{20.0g}{2.01g/mol}=9.95moles[/tex]
[tex]2H_2+O_2(g)\rightarrow 2H_2O[/tex]
According to stoichiometry :
2 moles of [tex]H_2[/tex] give = 2 moles of [tex]H_2O[/tex]
Thus 9.95 moles of [tex]H_2[/tex] will require=[tex]\frac{2}{2}\times 9.95=9.95moles[/tex] of [tex]H_2O[/tex]
Mass of [tex]H_2O=moles\times {\text {Molar mass}}=9.95moles\times 18g/mol=179g[/tex]
Thus 179 of [tex]H_2O[/tex] will be produced.
Given the equation representing a solution equilibrium: BaSO4(s) <—> Ba2+ (aq) + SO4 2- (aq)
What occurs when Na2SO4(s) is added to this system, increasing the concentration of SO4 2- (aq)?
1) The equilibrium shifts to the left, and the concentration of Ba2+(aq) decreases
2)The equilibrium shifts to the left, and the concentration of Ba2+(aq) increases
3)The equilibrium shifts to the right, and the concentration of Ba2+(aq) decreases
4)The equilibrium shifts to the right, and the concentration of Ba2+(aq) increases
Answer:
The equilibrium shifts to the left, and the concentration of Ba2+(aq) decreases
Explanation:
Whenever a solution of an ionic substance comes into contact with another ionic compound with which it shares a common ion, the solubility of the ionic substance in solution decreases significantly.
In this case, both BaSO4 and Na2SO4 both possess the SO4^2- anion. Hence SO4^2- anion is the common ion. Given the equilibrium;
BaSO4(s) <—> Ba2+ (aq) + SO4 2- (aq), addition of Na2SO4 will decrease the solubility of BaSO4 due to the presence of a common SO4^2- anion compared to pure water.
This implies that the equilibrium will shift to the left, (more undissoctiated BaSO4) hence decreasing the Ba^2+(aq) concentration.
1) The equilibrium shifts to the left, and the concentration of [tex]Ba^{2+}[/tex](aq) decreases
Conditions for equilibrium:Whenever a solution of an ionic substance comes into contact with another ionic compound with which it shares a common ion, the solubility of the ionic substance in the solution decreases significantly.
In this case, both BaSO₄ and Na₂SO₄ both possess the [tex]SO_4^{2-}[/tex] anion. Hence [tex]SO_4^{2-}[/tex] anion is the common ion.
Given the equilibrium;
[tex]BaSO_4(s) < = > Ba^{2+} (aq) + SO_4^{2-} (aq)[/tex],
The addition of Na₂SO₄ will decrease the solubility of BaSO₄ due to the presence of a common [tex]SO_4^{2-}[/tex] anion compared to pure water.
This implies that the equilibrium will shift to the left, (more undissociated BaSO₄ ) hence decreasing the [tex]Ba^{2+}[/tex]aq) concentration.
Find more information about Equilibrium here:
brainly.com/question/19340344
K + Li2O what is the product
Answer:
2K + Li2O → 2Li + K2O
Help ASAP.................
Answer:
Abiotic and Biotic factors?
ANSWER IT PLEASE!!!!! A virus is a genome, or set of chromosomes, contained inside a protein capsule called a capsid. A virus can be either a single or double strand of RNA or DNA. Although viruses are made of genetic information, they do not have cells. They also need to attach to a host cell in order to live and reproduce. Host cells can be from animals, plants and even bacteria and fungi. Scientists debate whether or not viruses are considered living organisms. Most agree that viruses are not living.
Which of these statements is true based on the information in the passage?
Answer:
?
Explanation:
What are the statements? You've given the passage but not the statements
A football player runs from the 50 yard line to the 20 in 3.4s seconds, what is his speed?
Answer:
8.8 yards per second
Explanation:
50 - 20 = 30 yards
30 yards/3.4 seconds = 8.8235
PLEASE HELP
Consider the chemical equations shown here.
3 equations. 1: upper N upper O gas plus upper O subscript 3 gas right arrow upper N upper O subscript 2 gas plus upper O subscript 2 gas. Delta H subscript 1 equals 198.9 kilojoules. 2: StartFraction 3 over 2 EndFraction upper O gas right arrow upper O subscript 3 gas. Delta H subscript 2 equals 142.3 kilojoules. 3: upper O gas right arrow one half upper O subscript 2 gas. Delta H subscript 3 equals negative 247.5 kilojoules.
What is DeltaHrxn for the reaction shown below?
NO(g)+O(g)->NO2(g)
Answer:
-304.1
I had this question and that’s what I got
Answer:
-867.7
Explanation:
yeah
What is an example of a polyatomic ion
Answer: The hydroxide cation (OH -) and the phosphate cation (PO 4 3-) are both polyatomic ions.
Explanation:
Answer:
OH - and PO 4 3- are both polyatomic ions
Why does dew form on the outside of your glass filled with ice cold water?
A student collects data during an experiment
Mass of empty beaker- 77.25
Mass of 100L water-100.0 g
Mass of salt- 20.0 g
Total mass-197.25 g
After the salt and water are mixed in the beaker and stirred for 1 minute what will be the mass of the contents
Answer:
The mass of the content = 120 g
Explanation:
Given:
Mass of empty beaker = 77.25 g
Mass of 100 L water = 100 g
Mass of salt = 20 g
Total mass = 197.25 g
Computation:
According to Law of Conservation of Mass:
According to the Law of Conservation of Mass, the physical and chemical properties of the substance changes during any type of physical or chemical process, but there is no change in their total mass.
So,
The mass of the content = Total mass - Mass of empty beaker
The mass of the content = 197.25 g - 77.25 g
The mass of the content = 120 g
What is the percentage composition of cobalt in cobalt(II) fluoride, CoF2?
Answer:
60.8%
Explanation:
We'll begin obtaining the molar mass of cobalt(II) fluoride, CoF2. This can be done as shown below:
Molar mass of CoF2 = 59 + (19x2) = 97g/mol.
The percentage composition of cobalt in cobalt(II) fluoride, CoF2 is given by:
Mass of Co/Molar Mass of CoF2 x 100
=> 59/97 x 100 = 60.8%
Therefore, the percentage composition of cobalt in cobalt(II) fluoride, CoF2 is 60.8%
If we start with 1.000g of strontium 90 0.953 grams will remain after 2.0 years (a) what is the half life of strontium 90 (b) how much strontium 90 will remain after 5.00 years Please show the necessary step
Answer:
a) 29.0 years
b) 0.89 g
Explanation:
Using the formula
t1/2= t×ln2/ln(No/Nt)
Where
Nt= mass of radioactive isotope at time= t =0.953g
No= initial mass of radioactive isotope present= 1.000g
t= time taken for N mass of radioactive isotope to remain = 2 years
t1/2 = half-life of radioactive isotope= ???
Substituting the values
t1/2= 2 × ln2/ln(1.000/0.953)
t1/2= 2× 0.693/0.048
t1/2= 29 hours
b)
N= No(1/2)^t/t1/2
Where t= 5 years
N= 1.000(1/2)^5/29
N= 1.000(1/2)^0.17
N= 0.89g
what is the most significant force that attracts water molecules to each other?
Answer:
Hydrogen Bonds
hope this helps
~Savannah :))
According to the forces of attraction, hydrogen bonds is the most significant force that attracts water molecules to each other.
What are forces of attraction?Forces of attraction is a force by which atoms in a molecule combine. it is basically an attractive force in nature. It can act between an ion and an atom as well.It varies for different states of matter that is solids, liquids and gases.
The forces of attraction are maximum in solids as the molecules present in solid are tightly held while it is minimum in gases as the molecules are far apart . The forces of attraction in liquids is intermediate of solids and gases.
The physical properties such as melting point, boiling point, density are all dependent on forces of attraction which exists in the substances.
Learn more about forces of attraction,here:
https://brainly.com/question/2122941
#SPJ2
1. In which order does food travel through the digestive
system after it is swallowed?
A. trachea, stomach, large intestine, small intestine
B. esophagus, stomach, small intestine, large intestine
C. stomach, esophagus, large intestine, small intestine
D. trachea, stomach, small intestine, large intestine Hurry!!
Answer:
B :)
Explanation:
Trachea is were oxygen is entered :D (5 stars?)
Which phrase provides the best definition of mass movement?
the movement of material caused by erosion
the slow flow of a glacier as it moves through the valley of a mountain
the movement of large amounts of soil and rock debris down a slope
the fast movement of a boulder rolling down a slope
Answer:
the movement of large amounts of soil and rock debris down a slope
Explanation:
yeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeetyeet
when does thermal energy stop moving
Answer:
at absolute zero.
Explanation:
absolute zero or 0 kelvin, is where all kinetic movement of electrons ceases in a molecule.
help me name these molecules please
Answer:
1. carboxylic acid
2. ether
3. ester
4. aldehyde
5. ketone
6. amine
7. alcohol
Explanation:
Know the functional groups. If you would like to learn them, let me know.
- Hope that helps! Please let me know if you need further 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%
Calculate the amount of heat released when the bottle (250g) of water is cooled from 30°C to 25°C. The specific heat of water is 4.186J/g Degree Celsius
Answer:
5232.5J
Explanation:
Data obtained from the question. This includes the following:
Mass (M) = 250g
Initial temperature (T1) = 30°C
Final temperature (T2) = 25°C
Change in temperature (ΔT) = T1 – T2 = 30°C – 25°C = 5°C
Specific heat capacity (C) = 4.186J/g°C
Heat (Q) =.?
The heat released can be obtained as follow:
Q = MCΔT
Q = 250 x 4.186 x 5
Q = 5232.5J
Therefore, the heat released is 5232.5J
The amount of heat released when the bottle (250g) of water is cooled is 5232.5J .
Given data:-
Mass (M) = 250g
Initial temperature (T1) = 30°C
Final temperature (T2) = 25°C
Change in temperature (ΔT) = T1 – T2 = 30°C – 25°C = 5°C
Specific heat capacity (C) = 4.186J/g°C
Heat (Q) =.?
The heat released can be obtained as follow:
[tex]Q = MC\delta T\\\\Q = 250\times 4.186 \times 5\\\\Q = 5232.5J[/tex]
Therefore, the heat released is 5232.5J.
To know more about:-
https://brainly.com/question/9424485
Whats the answer to 7/2 × 1/5?
Answer:7/10
Explanation:multiply top and bottom
Determine the volume occupied by 2.5 mol of a gas at 18 °C if the pressure is 81.8 kPa?
Answer:
74 litre
Explanation:
using ideal gas eqation PV=nRT
here P(pressure)=81.8 kPa =81.8×10^3 Pa
moles=2.5
temperature=273.15+18=291.15K
Gas constant R=8.314m^3-Pa/K-mol
now, V=nRT/P = 8.314×2.5×291.5/81.8×10^3 ≈74litre
✌️;)
What’s the two products of H2Co3
Answer:
Hydrogen and Cobalt
Explanation:
Break up each individual element
- Hope that helps! Please let me know if you need further explanation.
How many milliliters of 0.2 M NaOH are required to exactly neutralize 40 milliliters of 0.1 M HCl?
A) 10
B) 20
C) 40
D) 80
Answer:
Option B. 20mL
Explanation:
Step 1:
Data obtained from the question.
Volume of base (Vb) =..?
Molarity of base (Mb) = 0.2M
Volume of acid (Va) = 40mL
Molarity of acid (Ma) = 0.1M
Step 2:
The balanced equation for the reaction.
HCl + NaOH —> NaCl + H2O
From the balanced equation above, the following were obtained:
Mole ratio of the acid (nA) = 1
Mole ratio of the base (nB) = 1
Step 3:
Determination of the volume of base, NaOH needed for the reaction. This is illustrated below:
MaVa/MbVb = nA/nB
0.1 x 40 / 0.2 x Vb = 1
Cross multiply
0.2 x Vb = 0.1 x 40
Divide both side by 0.2
Vb = 0.1 x 40 / 0.2
Vb = 20mL
Therefore, the volume of the base is 20mL.
Consider the intermediate chemical reactions.
2 equations. First: upper C a (s) plus upper C upper O subscript 2 (g) plus one half upper O subscript 2 (g) right arrow upper C a upper C upper O subscript 3 (s). Delta H 1 equals negative 812.8 kilojoules. Second: 2 upper C a (s) plus upper O subscript 2 (g) right arrow 2 upper C a upper O (s). Delta H 2 equals negative 1, 269 kilojoules.
The final overall chemical equation is Upper Ca upper O (s) plus upper C upper O subscript 2 (g) right arrow upper C a upper C upper O subscript 3 (s).. When the enthalpy of this overall chemical equation is calculated, the enthalpy of the second intermediate equation
When the enthalpy of this overall chemical equation is calculated, the enthalpy of the second intermediate equation is halved and has its sign changed.
Let's consider the following intermediate chemical reactions.
Reaction 1: Ca(s) + CO₂(g) + ½O₂(g) → CaCO₃(s) ΔH₁ = -812.8 kJ
Reaction 2: 2 Ca(s) + O₂(g) → 2 CaO(s) ΔH₂ = -1269 kJ
We want to calculate the enthalpy of the following overall chemical equation.
CaO(s) + CO₂(g) → CaCO₃(s) ΔH = ?
We can apply Hess' law.
What is Hess' law?Hess' law states that regardless of the multiple stages or steps of a reaction, the total enthalpy change for the reaction is the sum of all changes.
To apply Hess' law in this case we have to:
Conserve equation 1 as is.Reverse equation 2 and multiply it by 1/2, thus changing the sign of its enthalpy and multiplying it by 1/2.Add both equations and their enthalpies.Ca(s) + CO₂(g) + ½ O₂(g) → CaCO₃(s) ΔH = -812.8 kJ
+
CaO(s) → Ca(s) + ½ O₂(g) ΔH = 634.5 kJ
--------------------------------------------------------------------------------------
CaO(s) + CO₂(g) → CaCO₃(s) ΔH = -178.3 kJ
When the enthalpy of this overall chemical equation is calculated, the enthalpy of the second intermediate equation is halved and has its sign changed.
The complete question is as follows.
Consider the intermediate chemical reactions.
Ca (s) + CO₂ (g) + ½O₂ (g) → CaCO₃ (s) ΔH₁ = -812.8 kJ
2Ca (s) + O₂ (g) → 2CaO (s) ΔH₂ = -1269 kJ
The final overall chemical equation is
CaO (s) + CO₂ (g) → CaCO₃ (s) ΔH = ?
When the enthalpy of this overall chemical equation is calculated, the enthalpy of the second intermediate equation
is halved and has its sign changed. is halved. has its sign changed. is unchanged.Learn more about Hess' law here: https://brainly.com/question/11628413
Answer:
Consider the following intermediate reactions.
CH₄(g)+2O₂(g)⇒CO₂(g)+2H₂O(g) ΔH₁ = -802 kJ
2H₂O(g)⇒2H₂O(I) ΔH₁ = - 88 kJ
The overall chemical reaction is as follows.
CH₄(g)+2O₂(g)⇒CO₂(g)+2H₂O(I) ΔH₂ = -890 kJ
What is the correct enthalpy diagram using the Hess law for this system?
✔️ A←❌ B
❌ C
❌ D
The half-life of gold-198 is 2.7 days. After
amount of gold-198 will remain.
days, 1/4 of the original
Answer: 8.1 days
Explanation:
Expression for rate law for first order kinetics is given by:
[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]
where,
k = rate constant
t = age of sample
a = let initial amount of the reactant = x
a - x = amount left after decay process= [tex]\frac{x}{4}[/tex]
a) to find rate constant
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
[tex]t_{\frac{1}{2}}=\frac{0.693}{k}[/tex]
[tex]k=\frac{0.693}{2.7days}=0.257days^{-1}[/tex]
b) for completion of one fourth of reaction
[tex]t=\frac{2.303}{k}\log\frac{x}{\frac{x}{4}}[/tex]
[tex]t=\frac{2.303}{0.257}\log{4}[/tex]
[tex]t=8.1days[/tex]
Thus after 8.1 days , one fourth of original amount will remain.
what is the reaccion when copper (II) carbonate, Cuco3(s), and
sulfuric acid, H2S04(aq), are mixed.
Answer:
Copper (II) oxide will react with sulfuric acid to create water and copper (II) sulfate. This reaction could be classified as a double displacement reaction or a neutralization reaction (metal oxides have basic properties in water).
so basically a neutralization reaction.
In general, when a substance changes from a solid to a liquid,
A.
the density of the substance increases.
B.
the substance no longer has density since density is a property only solids have.
C.
the density of the substance decreases.
D.
the density of the substance remains the same.
Answer:
c,density is the measure of compactness in a substance. Liquid particles are close together however they aren't as close as the particles in solids.
