has a Acids Bases
HCl LiOH
HBr NaOH
HI KOH
HNO 3
Chloe’s teacher gives her and her lab partner soil samples from different parts of the city: the park, the area next to a pond, the school, and a neighborhood. Chloe’s teacher also gives her a soil tester kit, which determines the pH of the soil. Chloe and her lab partner need to determine the pH of each soil sample and then compare them.
Fill in the blank with the word that best completes the statement.
This investigation is a(an)______investigation.
Answer:
an
Explanation:
It is AN because investigation starts with I ( i is a vowel). When there are vowels we use An.
Pls mark me brainliest!
How many liters of hydrogen (at 0.97atm and 24c) will produce 180 grams of water
I also need to know how to get the answer.
H₂ + ½O₂ → H₂O
2g → 18g
So, 18g water needs 2g H₂
So, 1g water needs 2/18g H₂
So, 180g water needs 2/18 x 180g H₂
→ 20 litres of H₂
Answer:
Explanation:
Molar mass of water, H2O = 2 + 16 = 18
So 180g of water contains 10M
H2 + O -> H2O
10M of Hydrogen is needed to produce 10M of water.
Molar volume at STP = 22.4L
So 10M of Hydrogen at STP = 224L
With Ideal Gas Law, P1V1/T1 = P2V2/T2
At STP, P1 = 1atm, T1=273K
At 0.97atm and 24c (273+24 = 297K), 10M of Hydrogen will take up:
1*224/273 = 0.97*V2/297
V2 = 224*297/273/0.97
= 251.23L
So the answer is 251.23L
why do objects cool down
Answer:
wla dyan ang sagut ehh baka mali yan
A doctor is testing a new medication and he doesn’t tell the people in the study about the possible side effects of the medicine. He is _____.
What is a natural disaster?
Answer:
Explanation:
A natural disaster is a major adverse event resulting from natural processes of the Earth; examples include floods, hurricanes, tornadoes, volcanic eruptions, earthquakes, tsunamis, storms, and other geologic processes
Answer:
A natural disaster is a natural, major harmful event resulting from natural processes of the Earth such as floods, earthquakes, or hurricanes, tornadoes, volcanic eruptions, tsunamis, storms, and other geologic processes that causes great damage or loss of life.
Describe the formation of calcium chloride (4 marks)
Answer:
It is an ionic compound that consists of one calcium cation Ca2+ and two chlorine anions. The bivalent calcium metal forms an ionic bond with two chlorine atoms. The formation of cacl2 happens mainly by reacting limestone (CaCo3) with hydrochloric acid (HCl).
The table below gives some characteristics of element Y.
Characteristics of element Y Values
Mass number 11
Number of neutrons in a single atom 6
Average atomic mass (grams/mole) 10.81
What is the identity of element Y?
Answer:
Boron B
Explanation:
According to the periodic table, Boron is the element with atomic mass of approximately 11 [i.e 10.81]
To calculate Neutrons
Neutrons = Mass number - Protons
Number of protons in Boron is same as atomic number which is 5
Thus, N = 11 - 5 = 6
explain how ships made of steel float on water
Answer:
The air that is inside a ship is much less dense than water. That's what keeps it floating
What is the empirical formula of a compound containing 5.03 g carbon, 0.42 g hydrogen, and 44.5 g of chlorine
Answer:
CHCl₃
Explanation:
We have the following data:
C = 5.03 g
H = 0.42 g
Cl= 44.5 g
First, we divide each mass by the molar mass (MM) of the chemical element to calculate the moles:
MM(C) = 12 g/mol
moles of C = mass/MM(C) = 5.03 g/(12 g/mol) = 0.42 mol C
MM(H) = 1 g/mol
moles of H = mass/MM(H) = 0.42 g/(1 g/mol) = 0.42 mol H
MM(Cl) = 35.4 g/mol
moles of Cl = mass/MM(Cl) = 44.5 g/(35.4 g/mol) = 1.26 mol Cl
Now, we divide the moles by the smallest number of moles (0.42):
0.42 mol C/0.42 = 1 C
0.42 mol H/0.42 = 1 H
1.26 mol Cl/0.42 = 3 Cl
Thus, the C:H:Cl ratio is 1:1:3.
Therefore, the empirical formula is CHCl₃
Answer:
CHCl₃
Explanation:
Which statement about the mass of an electron is correct? A The mass of an electron is equal to the mass of the proton. B The mass of an electron is less than the mass of the proton. с The mass of an electron is equal to the mass of a neutron. D The mass of an electron is greater than the mass of a neutron.
Answer:
B
Explanation:
because mass of an electron is 1/2000.
The statement about the mass of an electron which is correct is: B. The mass of an electron is less than the mass of the proton.
An atom refers to a smallest, indivisible unit that comprises the matter that forms all chemical elements. Therefore, atoms are typically considered as the fundamental building blocks of matter which determines the structure of a chemical element.
Basically, an atom consists of three (3) distinct particles and these include;
Protons. Neutrons. Electrons.
Electrons are the subatomic particles of a chemical element that are negatively charged with a magnitude of -1.
On the other hand, protons can be defined as the subatomic particles of a chemical element that are positively charged.
All of these subatomic particles of a chemical element has a mass. However, the mass of an electron is significantly less than the mass of proton, as a result of its extremely small size.
In conclusion, the mass of an electron is approximately 2000 times smaller than that of a proton and as such contributes almost nothing to the total mass of an atom.
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Lime is added to a lake to neutralize the effects of acid rain. The pH value of the
lake water rises from 4 to 7. What is the change in concentration of H+ ions in the
lake water?
Answer:
The change in concentration of H+ ions is -9.99×10⁻⁵
Explanation:
When pH rises, we talk about neutralization and, there is a decline in proton's concentration.
pH lower than 7 is acid
pH higher than 7 is basic
Protons are neutralized by hydroxides to make water as this:
H₃O⁺ + OH⁻ ⇄ H₂O
pH = - log [H₃O⁺]
[H₃O⁺] = 10^-pH
In conclussion: [H₃O⁺]₁ = 10⁻⁴ → 1×10⁻⁴
[H₃O⁺]₂ = 10⁻⁷ → 1×10⁻⁷
1×10⁻⁷- 1×10⁻⁴
The change in concentration of H+ ions is -9.99×10⁻⁵
How do countries with different currencies trade goods with each other?
A.
They trade actual physical products to avoid confusion over currency differences.
B.
They negotiate to determine which country's currency will be used for the whole exchange.
C.
They create a new shared currency, such as the European Union countries' euro.
D.
They use the exchange rate to convert one country's currency to another's.
Answer:
D- They use the exchange rate to convert one's Country's currency to another's
Explanation:
Question 14 of 30
Which of the following elements has 1 valence electron?
The Periodic Table
A. Sodium (Na)
B. Chlorine (CI)
C. Calcium (Ca)
D. Helium (He)
SUBMIT
Answer:
A. Sodium (Na)
Explanation:
The total number of electrons in the outermost principal energy level of an element is called the valence electrons of that element.
Na (11)---→1s2 2s2 2p6 3s1
There 1 electron in the outermost principal energy level of Sodium. So, the number of valence electron of Sodium is 11.
Answer:
Na
Explanation:
I was learning about it recently, that dude's right, it's Sodium
Which substance is a binary acid?
hydrochloric acid
phosphoric acid
nitrous acid
sulfuric acid
Answer:
A) Hyrdrochloric Acid
Explanation:
This is because binary acids are molecular compounds in which hydrogen is combined with a non-metal element. Hydrochloric acid has hydrogen present in it's compound, therefore identifying it as the only binary acid amongst the answer choices.
PLEASE HELP : Arrange the following elements into a food chain: plants, snake, Sun, hawk, and mouse.
Answer:
Plants ➯ Mouse ➯ Snake ➯ Hawk ➯ Sun
Explanation:
In Order As A Food Chain
The elements are arranged into food chain like plants ⇒Mouse ⇒ Snake⇒ Hawk ⇒ Sun.
What is element?A substance that could not be further decomposed according to any chemical reaction is known as a chemical element.
What is food chain?
The flow of nutrients as well as energy through such an ecosystem is described by a food chain. Energy is first produced by plants at the most fundamental level, and then it is used by higher-level species like herbivores. Energy is then transmitted from one carnivore to the next when they eat the herbivores.
The elements are arranged into food chain like plants ⇒Mouse ⇒ Snake⇒ Hawk ⇒ Sun.
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Explain why a mixture of copper (Il) Oxide and Magnesium reacts while there is no reaction when a mixture of Copper and Magnesium Oxide is heated.
Answer:
Copper oxide + magnesium = copper + magnesium oxide
Explanation:
When copper oxide is heated with magnesium powder, then magnesium oxide and copper are formed.. For example, magnesium is more reactive than copper. ... brown copper coats the surface of the magnesium.
What happens to the freezing point of a solution when more solute is added?
Which of the following statements regarding carbon is false? Group of answer choices Carbon has the capacity to form single and double bonds. Carbon has the ability to bond with up to six other atoms. Carbon has a tendency to form covalent bonds. Carbon has the ability to bond together to form extensive branched or unbranched "carbon skeletons."
Answer: The statement, carbon has the ability to bond with up to six other atoms is false.
Explanation:
Carbon is a group 14 element and it is a non-metal. The atomic number of carbon is 6 and its electronic distribution is 2, 4.
This means that there are 4 valence electrons present in it. Also, in order to attain stability a carbon atom forms only covalent bonds, that is, it shares its valence electrons with its own atoms or atoms of other elements.
Carbon has the capacity to form single and double bonds.
As valency of carbon is four so it can only combine to 4 other atoms vis single bond and it cannot bond with up to six other atoms.
Carbon shows the property of catenation, that is, it forms covalent bonds with its own atoms in a large number. So, carbon has the ability to bond together to form extensive branched or unbranched "carbon skeletons".
Thus, we can conclude that the statement, carbon has the ability to bond with up to six other atoms is false.
Identifying Changes of Matter
Which of these are chemical changes in matter? Check all tha
Answer:
In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed. The distinction between physical and chemical change is not clear cut.
Which kind of energy is stored in the chemical bonds of molecules found in
wood?
A. Mechanical energy
B. Potential energy
C. Gravitational energy
D. Kinetic energy
Answer:
B. Potential energy
Explanation:
It's not mechanical energy, because it is not doing work
It's not kinetic energy because it;s not moving
It's not gravitational energy because it is not above the ground
It is potential energy because it is stored energy
What is the general form of a synthesis reaction?
O A. AB + CD → AC + BD
B. A + B → AB
O C. AB + C → AC + B
D. AB → A+B
Be
The answer is B
Answer:
B. A+ B → AB
Explanation:
general form of a synthesis reaction
20 POINTS!!
What is the enthalpy of combustion when 1 mol C6H6(g) completely reacts with oxygen?
2C6H6(g) + 15O2(g) ? 12CO2(g) + 6H2O(g)
Options:
A. - 6339 kJ/mol
B. - 3169 kJ/mol
C. 1268 kJ/mol
D. 6339 KJ/mol
Answer:
-3169
Explanation:
trust the process
-3169 kJ/mol is the enthalpy of combustion when 1 mol [tex]C_6H_6(g)[/tex] completely reacts with oxygen.
Explanation:
Given:
The reaction of combustion of [tex]C_6H_6(g)[/tex] along with enthalpies of formation of the compounds.
To find:
The enthalpy of combustion when 1 mol [tex]C_6H_6(g)[/tex] completely reacts with oxygen.
Solution:
[tex]2C_6H_6(g) + 15O_2(g) \rightarrow 12CO_2(g) + 6H_2O(g)[/tex]
Enthalpy of the reaction:
[tex]\Delta H^o_{rxn}=\sum [\Delta H^o_{f,products}]-\sum [\Delta H^o_{f,reactants}]\\=[12mol\times \Delta H^o_{f.CO_2(g)}+6mol\times \Delta H^o_{f,H_2O(g)}]-[2 mol\times \Delta H^o_{f.C_6H_6(g)}+15\times \Delta H^o_{f,O_2(g)}]\\=[12mol\times (-393.50 kJ/mol)+6mol\times (-241.82 kJ/mol)]-[2mol\times 82.90kJ/mol+15mol\times 0 kJ/mol]\\=-6338.72 kJ[/tex]
[tex]2C_6H_6(g) + 15O_2(g) \rightarrow 12CO_2(g) + 6H_2O(g).\Delta H^o_{rxn}=-6338.72 kJ[/tex]
When 1 mole of [tex]C_6H_6(g)[/tex] reacts with oxygen gas:
[tex]=\frac{\Delta H^o_{rxn}}{\text{2 mol of } C_6H_6}\\=\frac{-6338.72 kJ}{2 mol}\\=-3169.36 kJ/mol\approx -3169 kJ/mol[/tex]
-3169 kJ/mol is the enthalpy of combustion when 1 mol [tex]C_6H_6(g)[/tex] completely reacts with oxygen.
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Calculate the standard enthalpy change for the reaction 2A+B⇌2C+2D Use the following data: Substance ΔH∘f (kJ/mol) A -235 B -413 C 193 D -493
Answer:
ΔH = 283kJ/mol
Explanation:
Using Hess's law, the ΔH of a reaction is equal to the sum of ΔH° of products times its coefficient subtracting the sum of ΔH° of reactants times its coefficient. Replacing, for the reaction:
ΔH = 2ΔH°C + 2ΔH°D - (2ΔH°A+ΔH°B)
ΔH = 2*193kJ/mol + 2*-493kJ/mol - (2*-235kJ/mol+ (-413kJ/mol)
ΔH = 283kJ/molHow many centimeters are in 5 miles? Hint: 1 miles = 5280 feet
Which of the following pairs of elements is most likely to form an ionic compound?
• magnesium and sodium
• nitrogen and sulfur
• oxygen and chlorine
• magnesium and chlorine
• carbon and fluorine
Explanation:
magnesium and sodium because they are minerals and part of iron
Why don’t scientists use the Bohr model above to explain charge transfer?
Answer:
nsksbsjensnsjeiejensbsksks
Hydrogen and nitrogen react to form ammonia. The chemical equation for this reaction is shown here. 3 H2(g) + N2(g) 2 NH3(g). What amount of hydrogen will produce 44.0 mol of ammonia?
66.0 mol
88.0 mol
132.0 mol
29.3 mol
Answer:
someone already answered but i think it's 132.0 mol too
what are the characteristics or properties that you can use to classify elements
Answer:
The number of outermost energy level electrons ( valency electrons )
The atomic number
An apple has been left out, and it is starting to rot. Which of the following is the best method to slow down the chemical changes that are occurring?
The best method is to keep rinsing the apple with water every hour.
The best method is to keep the apple in a cooler place.
The best method is to put the apple in the sun to warm it up.
The best method is to wrap the apple in plastic.
How many moles of oxygen are required to react with methanol in order to produce 13 moles of formaldehyde?
Answer:
6.5 moles of Oxygen are required
Explanation:
Based on the reaction:
CH3OH + 1/2 O2 → CH2O + H2O
1 mole of methanol reacts with 1/2 moles O2 to produce 1 mole of formaldehyde and 1 mole of water.
Thus, to produe 13 moles of formaldehyde, CH2O, are needed:
13 moles CH2O * (1/2mol O2 / 1mol CH2O) =
6.5 moles of Oxygen are required