Elements consist of tiny particles called atoms.
Atoms are the smallest units of an element that can participate in chemical reactions. They are incredibly tiny, with sizes on the order of 10^{-10} meters. Each element is made up of only one type of atom, and these atoms have a characteristic mass and chemical properties that are unique to that element.
Atoms themselves are composed of even smaller particles called subatomic particles. These include:
Protons: Positively charged particles located in the nucleus (center) of the atom.
Neutrons: Neutrally charged particles that are also found in the nucleus.
Electrons: Negatively charged particles that move around the nucleus in regions called electron clouds or shells.
Rosalinda wants to calculate the mass of Earth using Kepler’s laws or Newton’s universal law of gravitation.Which data would allow her to find the mass of Earth?
the mass of the Sun and the orbital period of the moon
the moon’s orbital period and distance from Earth
Earth’s distance from the Sun and the moon’s orbital period
Earth’s orbital period and distance from the Sun
Answer: B
Explanation:
How many resonance structures does NH₃ have?
What is the conversion of 160g to cg??
what type of bond dose a dimand have?
An atom is
a. the smallest unit of matter that maintains its chemical identity.
b. always made of carbon.
c. smaller than an electron.
d. the smallest unit of a compound.
Answer:
a. the smallest unit of matter that maintains its chemical identity.
Explanation:
Carbon-14 has a half-life of 5730 years. In a plant fossil, you find that the 14C has decayed to 1/4.00 of the original amount. How long ago was this plant alive?
Final answer:
Using the carbon-14 dating method, and knowing that the 14C in the fossil has decayed to 1/4 of its original amount, we can calculate that the plant was alive approximately 11,460 years ago.
Explanation:
In using carbon-14 dating to determine the age of a plant fossil, we utilize the known half-life of 14C which is approximately 5730 years. If the 14C has decayed to 1/4 of the original amount in the plant fossil, that means two half-lives have passed. As each half-life represents 5730 years, the age of the plant can be calculated by doubling this value. Therefore, we conclude that this plant was alive roughly 11,460 years ago.
Which substance is a binary acid?
hydrochloric acid
phosphoric acid
nitrous acid
sulfuric acid
Hydrochloric acid is a binary acid, while the other options are not.
Explanation:Out of the given options, hydrochloric acid is a binary acid. A binary acid is an acid that consists of hydrogen and a nonmetallic element. Binary acids are compounds composed of hydrogen and a nonmetal and participate in various chemical reactions, including acid-base reactions. They are used in chemical analysis and titration processes and are also used in industrial processes, such as the production of semiconductors and cleaning agents.
Hydrochloric acid (HCl) is commonly used to adjust pH levels in pools and water treatment. In hydrochloric acid (HCl), hydrogen and chlorine form a compound. Other options like phosphoric acid, nitrous acid and sulfuric acid are not binary acids as they contain additional elements along with hydrogen.
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Most ionic compounds tend to be classified as Select one:
a. fats
b. proteins
c. sugars
d. salts
A 8.048 gram sample of an organic compound containing C, H and O is analyzed by combustion analysis and 12.00 grams of CO2 and 3.684 grams of H2O are produced.
In a separate experiment, the molar mass is found to be 118.1 g/mol. Determine the empirical formula and the molecular formula of the organic compound.
The empirical formula is C2H3O2, and the molecular formula is C6H9O6.
To determine the empirical formula and the molecular formula of an organic compound from combustion analysis, follow these steps:
Convert the mass of CO2 and H2O to moles by dividing by their molar masses (44.01 g/mol for CO2 and 18.015 g/mol for H2O).Calculate the moles of C in CO2 and the moles of H in H2O (each mole of CO2 contains one mole of C, and each mole of H2O contains two moles of H).Convert these moles to grams of C and H.Subtract the mass of C and H from the original compound mass to find the mass of O.Convert the mass of O to moles by dividing by its molar mass (16.00 g/mol).Determine the simplest whole number ratio of C:H:O to find the empirical formula.Divide the molar mass of the compound by the mass of the empirical formula to find the ratio between the molecular and empirical formulas.Multiply the subscripts in the empirical formula by this ratio to determine the molecular formula.Using the provided data:
The moles of C in CO2: 12.00 g / 44.01 g/mol = 0.273 moles of C.The moles of H in H2O: 3.684 g / 18.015 g/mol = 0.2046 moles of H2, which equals 2 x 0.2046 = 0.4092 moles of H.The grams of C: 0.273 moles x 12.01 g/mol = 3.278 g of C.The grams of H: 0.4092 moles x 1.008 g/mol = 0.4125 g of H.The grams of O: 8.048 g - (3.278 g + 0.4125 g) = 4.3575 g of O.The moles of O: 4.3575 g / 16.00 g/mol = 0.2723 moles of O.C:H:O ratio is 0.273:0.4092:0.2723 which simplifies approximately to 1:1.5:1. This gives us the empirical formula CH1.5O.To get integers, we multiply each subscript by 2 to get C2H3O2 as the empirical formula.The molar mass of C2H3O2 is 43.05 g/mol. The molecular formula contains 118.1 g/mol / 43.05 g/mol = ~2.74 or approximately 3 times the empirical formula units, which gives us C6H9O6 as the molecular formula.how come the melting point of diesel petrol and rapeseed oil is only approximate?
How many atoms are in 11.9 moles of chromium?
Answer:
[tex]7,16.10^{24}[/tex]
Explanation:
We know that in 1 mole of any substances there are [tex]6,02. 10^{23}[/tex] atoms
This number ([tex]6,02. 10^{23}[/tex]) is a constant that is known as the avogadros number
if we know how many atoms are in a mole of chromium to calculate how many there are in 11.9 moles we apply a simple rule of three
[tex]1 mol Cr\longrightarrow 6,02.10^{23} atoms\\ 11.9 moles Cr\longrightarrow x\\x=\frac{(11.9)(6,02.10^{23})}{1}\\ x= 7,16.10^{24} atoms[/tex]
In 11.9 moles of chrome there are [tex]7,16.10^{24}[/tex] atoms
Sea water is _____.
an acid
a base
a neutral
Answer:
A neutral
Explanation:
Because sea water is neutral
Answer:
a neutral
Explanation:
Another important chemical property of water is its neutral pH. Pure water has pH value of 7. It is neither acidic nor basic. Living organisms cannot survive in highly acidic or basic environments.
Which type of institution employs the most forensic anthropologists on a full-time basis?
Answer: Government laboratories and educational institutions
Explanation:
Certain government institutions and educational institutions offers forensic anthropologists full time permanent jobs. These jobs are awarded on the basis of their research and teaching experience. They are placed as scientists or laboratory assistants in the laboratory and professors or lectarar in educational institutes.
Water is an example of a(n) _____.
Your answer is d ) a complex system
Which of the following elements has the most properties in common with molybdenum (Mo)?
A) manganese (Mn)
B) iron (Fe)
C) vanadium (V)
D) chromium (Cr)
D) Chromium (Cr)
______________
If Keq = 4 x 10^-7, which of the following is true?
A) products are favored
B) reactants are favored
C) there are no reactants remaining
D) reactants and products are present in equal amounts
2. What does a chemical reaction rate measure?
A) the amount of reactant used
B) energy change per unit of time
C) change in amount of reactant per unit of time
D) the amount of time needed for the reaction to come to completion
3. In an equilibrium reaction that makes more moles of gas than it consumes, what is the effect of increasing the pressure?
A) the reaction makes more reactants
B) the reaction makes more products
C) the reaction is unchanged
D) the answer cannot be determined
4. What is the effect of adding ore water to the following equlibrium reaction? CO2 + H20 <--> H2CO3
A) more H2CO3 is produced
B) there is no effect
C) the equilibrium is pushed in the direction of the reactants
D) CO2 concentration increases
5. Which of the following explains the increase in reaction rate from a catalyst?
A) more collisions between particles, so more successful collisions
B) catalysts do not increase the reaction rate
C) same number of collisions, but more are successful
D) fewer collisions but more successful
6. Which of the changes listed below would shift the following reaction to the right? 4HCI(g) + 02(g) <--> 2CL2(g) + 2h20(g)
A) increase of pressure
B) addition of Cl2
C) decrease of pressure
D) removal of 02
Final answer:
1. Reactants are favored. 2. A chemical reaction rate measures the change in amount of reactant per unit of time. 3. When an equilibrium reaction makes more moles of gas than it consumes, increasing the pressure favors the reactants.
Explanation:
1. If Keq = 4 x 10^-7, the equilibrium constant, then reactants are favored because the Keq value is very small, indicating that the concentration of products is much lower than the concentration of reactants.
2. A chemical reaction rate measures the change in the concentration of a reactant or product per unit of time, so the correct answer is C) change in amount of reactant per unit of time.
3. In an equilibrium reaction that makes more moles of gas than it consumes, increasing the pressure favors the side with fewer moles of gas. Therefore, the equilibrium will shift to the left, favoring the reactants.
4. Adding more water to the equilibrium reaction CO2 + H2O <--> H2CO3 will result in the equilibrium being pushed in the direction of the reactants because adding more water will decrease the concentration of H2CO3, favoring the formation of more CO2 and H2O.
5. A catalyst increases the reaction rate by providing an alternative reaction pathway with a lower activation energy, which leads to more successful collisions between particles. Therefore, the correct answer is A) more collisions between particles, so more successful collisions.
6. To shift the reaction 4HCl(g) + O2(g) <--> 2Cl2(g) + 2H2O(g) to the right, the equilibrium can be shifted by increasing the pressure, which will favor the side with fewer moles of gas, in this case the products. Therefore, the correct answer is A) increase of pressure.
Which property of water makes it helpful to use in car radiators?
A) Water can climb up the sides of a tube.
B) Water is a universal solvent.
C) Water takes long to heat and cool down than other liquids.
A sample of C3H8 has 6.72 x 10^24 H atoms.
What is the total mass of the sample?
To find the total mass of a C3H8 sample with 6.72 × 1024 H atoms, we calculate the number of moles of C3H8 and multiply it by the compound's molar mass to get approximately 61.5 grams.
Explanation:The question asks us to calculate the total mass of a sample of C3H8 (propane) given the number of H atoms in the sample. First, we determine the number of moles of H atoms by dividing the given number of H atoms by Avogadro's number (6.022 × 1023 atoms per mole), then use the molar ratio of H to C3H8 to find the moles of C3H8. We can then multiply the moles of C3H8 by its molar mass (the sum of the mass of 3 carbon atoms and 8 hydrogen atoms) to find the total mass of the sample.
Using the provided information, C3H8 has 8 H atoms per molecule. Therefore, if there are 6.72 × 1024 H atoms, that constitutes 6.72 × 1024 ÷ 8 = 8.4 × 1023 molecules of C3H8. One mole of C3H8 contains 6.022 × 1023 molecules, so the sample contains 8.4 × 1023 ÷ (6.022 × 1023) ≈ 1.395 moles of C3H8.
Next, we calculate the molar mass of C3H8: (3 × 12.011 amu for C) + (8 × 1.0079 amu for H) ≈ 44.1 g/mol. The total mass of the sample is therefore 1.395 moles × 44.1 g/mol = 61.5 grams.
. Which of the following is a balanced chemical equation for the synthesis of NaBr from Na and Br2?
Na + Br2 —> NaBr
2Na + Br2 —> NaBr
Na + Br2 —> 2NaBr
2Na + Br2 —> 2NaBr
Answer: The correct option is:
[tex]2Na+Br_2\rightarrow 2NaBr[/tex]
Explanation:
In balanced chemical equation , mass of the reactants is always equal to the mass of the products.
[tex]2Na+Br_2\rightarrow 2NaBr[/tex]
This is the balanced equation because on both sides number of sodium and bromine atoms are same.
On the reactant side there are two sodium atoms and two bromine atoms
On the product side there are also two sodium atoms and two bromine atoms in NaBr.
Mass of reactants (here 2Na and [tex]Br_2[/tex])= Mass of products(here 2NaBr)
2(23u) + 2(79.9u) = 2(23u + 79.9u) = 205 u
The correct balanced chemical equation for the synthesis of NaBr from Na and Br₂ is: 2Na + Br₂ → 2NaBr. Therefore, the correct option is option C.
A balanced chemical equation is a representation of a chemical reaction using chemical formulas and symbols. In a balanced equation, the number of atoms of each element is the same on both sides of the equation. This means that the total mass and the total charge remain constant during the chemical reaction.
The balanced equation provides important information about the reactants and products involved in the reaction, as well as the stoichiometry (the molar ratio) between them. It follows the law of conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction, only rearranged.
Thus, the ideal selection is option C.
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Why are electrons important?
Persamaan setara pada reaksi besi dengan asam klorida membentuk besi (II) klorida dan gas hidrogen
Iron reacts with hydrochloric acid to form Iron II Chloride and hydrogen gas. This is a single displacement reaction common in chemistry. Hess's Law can be employed to understand the energy changes in the reaction.
Explanation:The question refers to the chemical reaction of iron (Fe) with hydrochloric acid (HCl) to form Iron (II) Chloride (FeCl2) and hydrogen gas (H2). The balanced chemical equation for this reaction is: Fe + 2HCl -> FeCl2 + H2.
This is an example of a single displacement or substitution reaction, where element (iron) reacts with a compound (hydrochloric acid) to form a new compound (Iron II Chloride) and another element (hydrogen gas). Such reactions are common in Chemistry and understanding them helps comprehend how different substances interact. Hess's Law can also be applied here to understand the energy changes that occur during this reaction.
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How many electrons does nitrogen (N) need to gain to have a stable outer electron shell
Answer: 3 more electrons
Explanation: Generally elements with inert gas configuration are more stable. It is also called as Octet rule.
It tells that, elements which have electrons equal to atomic number of inert gases (2,8,10,18,36 etc) in their valency shell are exceptionally stable.
Here in our case, nitrogen has atomic number-7, 1s2 2s2 2p3
Here N has 5 electrons in valency shell , hence it needs 3 more electrons to get octet configuration.
So answer is 3 Electrons
The outer electron shell of nitrogen (N) contains 5 electrons. It would need to obtain 3 electrons to fill its shell with 8 electrons in order to have a stable outer electron shell.
An element's capacity to maintain its current state or withstand any changes under usual circumstances is referred to as stability. The fact that it guarantees an element's durability and versatility across a range of applications makes it a desirable property. Depending on the situation, stability can have a variety of meanings. Chemical stability, which refers to an element's resistance to reactions or decomposition when exposed to various chemical environments, is a crucial component of stability. Strong chemical bonds that take a lot of energy to break are common in elements with high chemical stability. The outer electron shell of nitrogen (N) contains 5 electrons. It would need to obtain 3 electrons to fill its shell with 8 electrons in order to have a stable outer electron shell.
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Which chemical equation is unbalanced?
1.C + O2 → CO2
2.Sr + O2 → 2SrO
3.6H2 + 3O2 → 6H2O
4.H2 + H2 + O2 → H2O + H2O
The correct option is 2.
For a chemical equation to be balanced, the number of atoms of each element present in the reactants must be the same with that present in the products. If the number of atom of any element at any of the two side of the reaction is not the same, then the equation is not balanced. Looking at the options given above, it will be noticed that for option 2, the number of Sr atom at the reactant side is 1 while at the product side it is 2. This shows that the equation is not balanced.
The unbalanced chemical equation is [tex]\boxed{2.{\text{ Sr}} + {{\text{O}}_2} \to {\text{SrO}}}[/tex].
Further explanation:
Chemical reaction:
The chemical conversion of one set of substances into another is termed as chemical reaction. The substances that were originally present before the occurrence of chemical reaction are known as reactants whereas the substances that are formed once the reaction goes to completion are called products. Any chemical reaction involves the bond breaking between the reactants and new bond formations occur in products.
The chemical reaction in which equal number of atoms of the different elements is present in the reactant as well as in the product side is known as balanced chemical reaction. Law of mass and energy conservation are followed by each and every balanced equation.
1. [tex]{\text{C}} + {{\text{O}}_2} \to {\text{C}}{{\text{O}}_{\text{2}}}[/tex]
On the reactant side,
Number of carbon atoms is 1 while that of oxygen atoms is 2.
On the product side,
Number of carbon atoms is 1 while that of oxygen atom is 2.
The number of atoms of each type is the same on both sides of the reaction and therefore this reaction is balanced.
2. [tex]{\text{Sr}} + {{\text{O}}_2} \to {\text{2SrO}}[/tex]
On the reactant side,
Number of strontium atoms is 1 while that of oxygen atoms is 2.
On the product side,
Number of strontium atoms is 2 while that of oxygen atom is 2.
The number of strontium atoms on both sides of the reaction is not same and therefore this reaction is unbalanced.
3. [tex]{\text{6}}{{\text{H}}_2} + 3{{\text{O}}_2} \to {\text{6}}{{\text{H}}_2}{\text{O}}[/tex]
On the reactant side,
Number of hydrogen atoms is 12 while that of oxygen atoms is 6.
On the product side,
Number of carbon atoms is 12 while that of oxygen atom is 6.
The number of atoms of each type is the same on both sides of the reaction and therefore this reaction is balanced.
4. [tex]{{\text{H}}_2} + {{\text{H}}_2} + {{\text{O}}_2} \to {{\text{H}}_2}{\text{O}} + {{\text{H}}_2}{\text{O}}[/tex]
On the reactant side,
Number of hydrogen atoms is 4 while that of oxygen atoms is 2.
On the product side,
Number of hydrogen atoms is 4 while that of oxygen atom is 2.
The number of atoms of each type is the same on both sides of the reaction and therefore this reaction is balanced.
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Answer details:
Grade: High School
Subject: Chemistry
Chapter: Chemical reactions and equations
Keywords: balanced, unbalanced, Sr, O2, H2, H2O, C, reaction, conversion, reactants, products, SrO, CO2.
A uranium atom has 92 protons in its nucleus. how many electrons does it have?
Which property of water makes it helpful to use in car radiators?
A) Water can climb up the sides of a tube.
B) Water is a universal solvent.
C) Water takes long to heat and cool down than other liquids.
Acetone and sodium chloride both have similiar mass. Explain why their other properties differ.
Acetone: C3H6O, melting point = −94°C, liquid at room temperature, low electrical conductivity
Sodium chloride: NaCl, melting point = 801°C, solid at room temperature, high electrical conductivity
Acetone is a covalent compound, whereas sodium chloride is an ionic compound.
Covalent compounds have strong bonds that do not break apart like ionic compounds do, and they do not conduct electric charge in solution.
Covalent compounds do not have strong attractions between molecules and so have very low melting points, unlike ionic compounds.
Analyze the properties of a sodium atom and a sodium ion. What are the differences in mass, stability, and reactivity that are caused due to the differences between the sodium atom and sodium ion? ...?
Which statement is correct about honey?
It contains disaccharides, a complex type of lipid.
It contains monosaccharides, the simplest carbohydrate.
It contains starch, which gives it a sweet taste.
It contains lipids, which give it a sweet taste.
who first published the classification of the elements that is the basis of our periodic table today
Dmitri Mendeleev was the first to publish the classification of the elements that is the basis of our current Periodic Table, by grouping them in order of atomic weight and similar chemical properties in 1869.
Explanation:The classification of the elements that is the basis of our periodic table today was first published by Dmitri Mendeleev in 1869. Mendeleev's table, also known as the Mendeleev periodic table, was the first to order the elements by atomic weight and to group them based on their chemical properties. Mendeleev even left vacant spaces in his table for elements that he predicted would be discovered in the future. His predictions were remarkably accurate and gave rise to the systematic table we use today.
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The distance between the atoms of H−I is 1.61Å. What is the distance in meters?