Five strategies needed by learners to acquire knowledge and skills to make informed decisions and take appropriate actions to ensure availability of clean water
Lavoisier's discovery that air was not a substance but rather a mixture of nitrogen and oxygen is described as history-making. why do you think this description is accurate?
chemistry
how do you count atoms?
4 HNO3
To count atoms in 4 HNO3, the coefficient 4 is multiplied with the number of each type of atom. It results in 4 hydrogen atoms, 4 nitrogen atoms, and 12 oxygen atoms.
To count atoms in a chemical formula like 4 HNO3, you look at the coefficients and subscripts. The coefficient (4 in this case) tells us how many molecules of HNO3 there are. We multiply this by the number of each type of atom within one molecule. Nitric acid (HNO3) has one hydrogen (H), one nitrogen (N), and three oxygen (O) atoms. Therefore, to count the atoms in 4 HNO3, we do the following: 4 molecules of HNO3 each contain 1 H atom, giving us a total of 4 H atoms; 4 molecules have 1 N atom each which is a total of 4 N atoms; and 4 molecules each have 3 O atoms, resulting in 12 O atoms in total. So, 4 HNO3 contains 4 hydrogen atoms, 4 nitrogen atoms, and 12 oxygen atoms.
Does the density of ice affect the melting rate of ice, or does adding objects affect melting rates? I'm going to need evidence of some kind. If not, that's okay.
How many nanoseconds are there in one minute?
These substances are made up of two or more elements chemically combined?
True or false a homogeneous mixture is a mixture in which it is difficult to distinguish the substances from one another
Repulsion between closely packed protons in the nucleus is overcome by
Answer:
Strong nuclear force
Explanation:
As we know that positive charges repel each other so protons do repel each other although atoms are stable because of strong nuclear force acting between nucleons (protons and neutrons in nucleus are called nucleons) which overcome the repulsive force between the proton. Strong nuclear force is very short-range force and acts only in distance of angstrom or picometre.
In each vertical column, or group, of the periodic table, the elements have ____.
a. similar chemical and physical properties
b. different chemical and physical properties
c. similar physical but different chemical properties
d. different physical but similar chemical properties
In each vertical column or group of the periodic table, elements have similar physical and chemical properties.
What is periodic table?Periodic table is a tabular arrangement of elements in the form of a table. In the periodic table, elements are arranged according to the modern periodic law which states that the properties of elements are a periodic function of their atomic numbers.
It is called as periodic because properties repeat after regular intervals of atomic numbers . It is a tabular arrangement consisting of seven horizontal rows called periods and eighteen vertical columns called groups.
Elements present in the same group have same number of valence electrons and hence have similar properties while elements present in the same period show gradual variation in properties due to addition of one electron for each successive element in a period.
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What happens to matter if we add or take away energy
How many protons and neutrons does a silicon si atom have and hwere are each of there subatomic particles located how many electrons does a silicon atom have?
What is the concentration of nitrate ions in a 0.225 msr(no3)2 solution?
We are given that there are 2 moles of NO3 from the 0.225 M Sr(NO3)2 solution. Therefore we simply use stoichiometry to solve this problem.
Concentration NO3 = 0.225 M Sr(NO3)2 * (2 moles NO3 / 1 mole Sr(NO3)2)
Concentration NO3 = 0.45 M
Answer : The concentration of nitrate ions is 0.450 m.
Solution : Given,
Molarity of [tex]Sr(NO_3)_2[/tex] = 0.225 m
The balanced ionic equation is,
[tex]Sr(NO_3)_2\rightarrow Sr^{+2}+2NO^-_3[/tex]
From the reaction, we conclude that the 1 mole of [tex]Sr(NO_3)_2[/tex] produces 2 moles of [tex]NO^-_3[/tex] ions. That means the concentration of nitrate ions is twice the value of [tex]Sr(NO_3)_2[/tex].
then, 0.225 m of [tex]Sr(NO_3)_2[/tex] gives 2 × 0.225 of [tex]NO^-_3[/tex] ions
Now the concentration of [tex]NO^-_3[/tex] ions is equal to 0.450 m.
2. You have 2 m3 of a mineral ore sample. It has a mass of 1 × 104 kg. Calculate the density of the ore sample and express your results in g/cm3 with appropriate scientific notation.
Which mass measurement contains four significant figures? 1. 0.086 g 2. 0.431 g 3. 1003 g 4. 3870 g
Answer :
(1) The given number in 4 significant figures will be, [tex]8.600\times 10^{-2}g[/tex]
(2) The given number in 4 significant figures will be, [tex]4.310\times 10^{-1}g[/tex]
(3) The given number in 4 significant figures will be, [tex]1.003\times 10^3g[/tex]
(4) The given number in 4 significant figures will be, [tex]3.870\times 10^3g[/tex]
Explanation :
Significant figures : The figures in a number which express the value -the magnitude of a quantity to a specific degree of accuracy is known as significant digits.
(1) The given number 0.086 g converted into 4 significant figures.
In 0.086 g, there are 2 significant figures. Now we have to convert it into 4 significant figures.
The given number in 4 significant figures will be, [tex]8.600\times 10^{-2}g[/tex]
(2) The given number 0.431 g converted into 4 significant figures.
In 0.431 g, there are 3 significant figures. Now we have to convert it into 4 significant figures.
The given number in 4 significant figures will be, [tex]4.310\times 10^{-1}g[/tex]
(3) The given number 1003 g converted into 4 significant figures.
Now we have to convert it into 4 significant figures.
The given number in 4 significant figures will be, [tex]1.003\times 10^3g[/tex]
(4) The given number 3870 g converted into 4 significant figures.
Now we have to convert it into 4 significant figures.
The given number in 4 significant figures will be, [tex]3.870\times 10^3g[/tex]
Which group contains elements whose atoms have six electrons in their valence shell?
how many mg are there in a 5.00 grain aspirin tablet ? 1 grain = 0.00229 oz . there are 454 g/lb
To convert the mass of a 5.00-grain aspirin tablet to milligrams, convert grains to ounces, ounces to grams, and grams to milligrams. A 5.00-grain aspirin tablet is approximately 324.56 milligrams.
Explanation:The question is asking to convert the mass of a 5.00-grain aspirin tablet into milligrams. Since 1 grain is equal to 0.00229 ounces, we first need to convert ounces to grams and then to milligrams. We know that there are 28.3495 grams in an ounce, and 1 gram is equal to 1000 milligrams.
First, convert 5.00 grains to ounces:
5.00 grains * 0.00229 oz/grain = 0.01145 oz
Next, convert 0.01145 ounces to grams:
0.01145 oz * 28.3495 g/oz = 0.324555675 grams
Lastly, convert grams to milligrams:
0.324555675 g * 1000 mg/g = 324.555675 mg
Therefore, a 5.00-grain aspirin tablet is approximately 324.56 milligrams.
One liter of a solution ph 9 has how many more hydroxide ions (oh-) than 1 l of a solution of ph 4?
A solution with a pH of 9 has 100,000 times more hydroxide ions than a solution with a pH of 4 due to the corresponding pOH values and hydroxide ion concentrations based on the relationship between pH and pOH.
Explanation:The student has asked about the difference in the number of hydroxide ions between a solution with a pH of 9 and another with a pH of 4. Using the relationship PH + pOH = 14, we can find the pOH.
For the pH 9 solution, the pOH would be 5 (14 - 9), which corresponds to a [OH-] of 1.0 × 10-5 M. For the pH 4 solution, the pOH would be 10 (14 - 4), corresponding to a [OH-] of 1.0 × 10-10 M. Hence, the pH 9 solution has 1.0 × 10-5 M of OH-, which is 100,000 times greater than the 1.0 × 10-10 M OH- in the pH 4 solution.
Matter that is composed of two or more different elements chemically combined in a fixed proportion is classified as...
Determine the oxidation state of the transition metal in each of these coordination compounds.
Is a substance that a filter can seperate into two parts a mixture or a pure substance?
Of the molecules sicl4 and sii4, which has bonds that are more polar?
Answer:
Since the electronegativity difference between the atoms is greater in SiCl4 , it has bonds that are more polar when compound to the other compound.
Explanation:
Need help for the last questions!
Two or more atoms held together by covalent bonds is called a(n) __________
Electrons in an atom may only have certain energy. because of this, the energy of the electrons in an atom is said to be ________.
The energy of the electrons in an atom is said to be quantized, meaning electrons can only have certain specific energy levels. These levels are characterized by quantum numbers, like the principal quantum number 'n', indicating different shells or orbits for the electrons.
Electrons in an atom may only have certain energy levels. This is because the energy of the electrons in an atom is said to be quantized. This means that the electrons can only possess specific amounts of energy, corresponding to distinct energy levels.
Niels Bohr suggested that electrons are restricted to certain orbits, and therefore, they can only have certain energy levels. Each energy level is described by quantum numbers, which are integer values that characterize the arrangement of electrons within an atom. For example, the principal quantum number, represented as 'n,' indicates different energy shells or levels, with higher 'n' values generally signifying higher energies.
Electrons are organized into energy shells labeled by the principal quantum number 'n', where the higher the energy of a shell, the farther (on average) it is from the nucleus. Each shell can contain a set number of electrons and the higher the shell number, which correspondingly indicates a higher energy level.
When a substance changes its state, all BUT ONE of these statements is true. That is
A) Mass remains constant.
B) Only the form changes.
C) Kinetic energy changes.
D) Something new is formed.
Answer:
D . Something new is formed.Explanation:
The option A, B and C are true statement while D is false statement.
Mass remains constant.
During a physical change mass remain constant, just state change.Only the form changes.
During a physical change ,just state changeKinetic energy changes.
During a physical change ,kinetic energy also change because liquid, solid and gases have different inter molecular forces which relate to K.E.Something new is formed.
when substance change state, then it remained as such as before, just its state change, not composition.Energy is expended when a force moves matter across a distance.
True
False
The conservation of mass-energy and the first law of thermodynamics are synonymous.
True
False
Temperature and thermal energy are synonymous terms.
True
False
On the Kelvin scale, temperatures are expressed as positive values only.
True
False
The amount of heat transfer required to change the temperature of one gram of water one degree Celsius is also known as a calorie.
True
False
How many moles of sodium iodide are needed to remove 5.95×10−6 mol of o3?
Final answer:
Assuming a 1:1 molar ratio, the number of moles of sodium iodide needed to remove [tex]5.95\times10^-^6[/tex] mol of ozone is also [tex]5.95\times10^-^6 mol[/tex].
Explanation:
To calculate the number of moles of sodium iodide (NaI) required to remove a certain number of moles of ozone [tex](O_3)[/tex], we need to know the stoichiometry of the reaction between NaI and [tex]O_3[/tex]. This information is not provided, so we'll have to assume it is a 1:1 molar ratio, which is typical for direct redox reactions where one molecule reacts with another one-on-one.
Under the assumption of a 1:1 molar ratio, to remove [tex]5.95\times10^-^6 mol[/tex] of [tex]O_3[/tex], you would need an equal amount of NaI, which would also be [tex]5.95\times10^-^6 mol[/tex] of NaI. We are assuming a straightforward reaction where one mole of [tex]O_3[/tex] reacts with one mole of NaI to form products.
Write the formula for barium nitrite. write the formula for barium nitrite. bn ba(no2)2 ba3n2 b(no2)3 bano3
The formula for Barium nitrite is Ba(NO₂)₂. This is because barium has a +2 charge and nitrite has a -1 charge, so two nitrite ions are needed to balance the charge of the barium ion. So correct option is a.
a) Ba(NO₂)₂.
Barium nitrite is a chemical compound formed by the combination of the elements barium (Ba) and nitrite (NO₂). To understand the formula of barium nitrite, let's break down the composition of the compound:
1. Barium (Ba):
Barium is a metallic element with the chemical symbol "Ba." It belongs to the alkaline earth metal group, which is located in group 2 of the periodic table. Barium is a highly reactive metal that readily forms compounds with other elements.
2. Nitrite (NO₂):
Nitrite is a polyatomic ion composed of one nitrogen atom (N) and two oxygen atoms (O). Its chemical formula is NO₂. Nitrite is negatively charged due to the presence of two extra electrons, which gives it a -1 charge.
The chemical formula of barium nitrite is Ba(NO₂)₂.
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If an isotope has an atomic number of 8 and a mass number of 18 how many neutrons
California’s rice fields are _______.
a.
visited by migrating waterfowl
b.
flooded during the summer
c.
a source of wild bird meat
d.
all of the above
Answer:
a just took the test on engenuity
Explanation:
hope dis helps : p
California’s rice fields are visited by migrating waterfowl. Hence option a is correct.
What is migration?Migration is defined as movement from one nation, location, or neighborhood to another in quest of greater chances for settling. The primary beneficial consequences of migration on host countries are the growth of the labor force, the diversification of cultures, the filling of skill gaps in the labor market, and the improvement of local economies. Differences in income and economic opportunities between nations, varied levels of social and human security, and preexisting ethnic and diaspora networks are the main drivers of international migration.
Waterfowl are birds with waterproof feathers and webbed feet that can swim well. They propel themselves through the water by using their webbed feet as flippers. Waterfowl frequently have webbed feet, rounded bodies, long necks, and short wings. Near water bodies, waterfowl typically build their nests on the ground. Some are an exception to this rule, such as the Common Merganser and Wood Duck, which lay their eggs in nest boxes or cavities in trees.
Thus, California’s rice fields are visited by migrating waterfowl. Hence option a is correct.
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