Answer:
24×10^-3Explanation:
[tex]Move \: the\:decimal \:point\:,\\3 \:times\:to\:the \:right = 24\\\\When \:the\:decimal\:point \: moves\\\:to\:the \:right\:it\:becomes\:a \:negative\:power\\\\0.024= 24 \times 10^-^3[/tex]
how many oxygen atoms are in 7.25g of calcium nitrate
Answer:
The answer to this question is approximately equal to 1.6 ×
[tex] 1.6 \times {10}^{23} atom \: o[/tex]
An element’s most stable ion forms an ionic compound with bromine, having the formula XBr2. If the ion of element "X" has a mass number of 230 and has 86 electrons, what is the identity of the element, and how many neutrons does it have?
Answer:
88
Explanation:
The ion has a charge of 2+, therefore the number of neutrons it possess is 86+2
which equals 88
The element X having a mass number of 230 and has 86 electrons is radium and has 142 neutrons.
An atom is composed basically of electrons, protons and neutrons. In a neutral atom, the number of protons and electrons are equal. The number of neutrons is the difference between the mass number and the number of protons (atomic number).
Since we know that the ion of the element X has 86 electrons and the compound formed is XBr2, it then means that neutral X has 88 electrons.
The number of electrons in the neutral atom is the same as the number of protons or atomic number. An element can be identified by its atomic number. The element having atomic number 88 is radium.
The number of neutrons is obtained as;
Mass number - atomic number
230 - 88 = 142 neutrons
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Atoms of elements X, Y and Z have 16, 17 and 19 electrons, respectively. Atoms of argon have 18 electrons.
a Determine the formulae of the compounds formed by the combination of the atoms of the elements:
(i) X and Z
(ii) Y and Z
(iii) X with itself.
b In each of the cases shown in
A (i)–(iii) above, name the type of chemical bond formed.
c Give two properties you would expect to be shown by the compounds formed in an (ii) and an (iii).
Answer:
a 1) XZ2
2) YZ
3) X2
b 1) Ionic bond
2) Ionic bond
3) covalent bond
c) ionic compounds has high melting and boiling point
ionic compounds can conduct electicity in aqueous form
covalent compounds have electrons shared between the atoms
covalent compounds have lower melting point compared to ionic compound
Answer:
(i) XZ = Potassium Sulfide [K2SO4]
(ii) YZ = Potassium Chloride [KCI]
(iii) X = Sulfur [S]
b) (i) Ionic Bond. (ii) Ionic Bond. (iii) Covalent Bond.
c) (i) Ionic compounds have high melting and boiling points.
(ii) Ionic compounds can conduct electricity in a molten state or a solution as they have ions that can move and carry charge.
(iii) Covalent compounds have low melting and boiling points.
(iv) Covalent compounds can not conduct electricity as all electrons are involved in bonding so there are no free electrons or ions to carry the charge.
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A chemical equation is balanced when Group of answer choices the number of atoms of each element is the same in reactants and products. the charge on each atom is the same in reactants and products. the sum of the coefficients of the reactants is equal to the sum of the coefficients of the products. the total number of ions is the same in reactants and products. the total number of molecules is the same in reactants and products.
Answer:
a
Explanation:
A chemical equation is said to balanced only when the number of atoms of each element is the same in both reactants and products side. Rest all options are absurd. Hence, option a is correct.
Balancing of the reaction has no relation with coefficient, molecules or charge of the elements
Explain how the energy of a toy car is transformed as it slides down a ramp. Give evidence that the energy of the car remains the same at all points on the ramp. (30 points)
Answer:
As the car starts to slide down the ramp, it is kinetic energy and when it's on the top of the ramp, it is potential energy. We can see that the energy is now being transferred through the car and ramp.
Ytu perform an electrolysis reaction using FeCl, iron (1) chloride. Which of the following will happen?
A. Chlorine will move to the positive electrode and become reduced.
B. Iron will move to the positive electrode and become oxidized.
C. Chlorine will move to the negative electrode and become oxidized.
D. Iron will move to the negative electrode and become reduced.
Answer:
The answer is "Option B"
Explanation:
when we react with FeCl, iron, and chloride to both the electrolysis. So, iron is charged positive ion, as well as passes to the negative, is cathode electrode. But there is a decrease in the cathode.
The equation can be defined as follows:
[tex]FeCl_2[/tex] [tex]\longrightarrow[/tex][tex]Fe + Cl_2[/tex]
In the above equation, when the iron chloride electrolysis solution, it will give the iron(II) and the chlorine. This process happens when the hydrogen chloride solution at a temperature of about 90 ° C.
Answer: D
Explanation: As Fe is positive charged while chlorine is negative charged.
(D) is correct. As iron moves to negative and it get reduce as negative electrode is cathode
calculate the pH of 500cm3 of 0.2mol/dm3 Ca(OH2), assume complete ionisation
Answer:
The pH of 500 cm³, 0.2 mol/dm³, Ca(OH₂) is ≈ 13.6
Explanation:
The given parameters are;
Concentration of the calcium hydroxide, Ca(OH₂) = 0.2 mol/dm³
Volume of the calcium hydroxide, Ca(OH₂) = 500 cm³
Given that the calcium hydroxide, Ca(OH₂), undergoes complete ionization in water, complete dissociation, we have;
Ca(OH₂) ⇄ Ca²⁺ + 2 OH⁻
Therefore, we have;
2 moles of [OH⁻] for each mole of Ca(OH₂) which gives the concentration of [OH⁻] as
[OH⁻] = 2 × 0.2 ≈ 0.4 mol/dm³
The pH is given by the formula
pH = 14 + ㏒₁₀ [OH⁻]
pH = 14 + ㏒₁₀ (0.4) = 14 - 0.3979 = 13.6021 ≈ 13.6
The pH of the 500 cm³ 0.2 mol/dm³ Ca(OH₂) ≈ 13.6.
the overall take away of an experiment’s results is the______. A. hypothesis B. introduction C. conclusion
Answer:
conclusion
Explanation:
it can't be a hypothesis since tests are carried out to verify so it is not a theory
an introduction to an experiment only gives the basis of what we are investigating therefore nothing has been proven and the question is still unanswered
The overall takeaway of an experiment’s results is the conclusion. Hence, option C is correct.
What is a hypothesis?A hypothesis is a testable statement about the relationship between two or more variables or a proposed explanation for some observed experiment.
The overall takeaway of an experiment’s results can't be a hypothesis since tests are carried out to verify so it is not a theory
An experiment only gives an idea about the investigation therefore nothing has been proven and the question is still unanswered.
Hence, the overall takeaway of an experiment’s results is the conclusion.
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If an object's mass is 70 g, and its volume is 10cm cubed, what is its density?
If an object's mass is 70 g, and its volume is 10cm cubed, its density is 7 centimeter cube.
What is density?The density of any solid substance is the unit of the area occupied by it in per centimeter of the cube of the volume in the given sample and calculated by dividing the mass and the volume of the compound unit will be centimeter cube.
The mass of the given object is 70 gram and the volume is given is 10 cm to find the density,
Density = mass of object / volume of object
substituting the value in the formula,
Density = 70 / 10
Density = 7 centimeter cube.
Therefore, the density of the given object will be 7 centimeter cube if an object's mass is 70 g, and its volume is 10cm cubed.
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Undulation in sandy material is called
cross-beds
ripple marks
mud cracks
O fossils
Answer:
ripple marks
Explanation:
Undulation is defined as the to and fro wavelike motion in a fluid or elastic medium.
Undulation in sandy material is called ripple marks because ripple marks are the sediments of rocks that show wavy structure at its surface due to agitation by water and wind.
Hence, the correct answer is "ripple marks".
pls balance the following chemical equation asap; Ca(OH)2 +CO2 = CaCO3+ H2O pls make it step by step
Answer:
Explanation:
Start by writing water as HOH
Ca(OH)2 +CO2 = CaCO3+ HOH
Next pay attention to the CO2 going to CO3
We need an oxygen.
Fortunately that is provided by the (OH)2
Now we have
Ca(OH)2 + CO2 ==> CaCO3 + HOH
and believe it or not, that is balanced as it is
The left side has 1 Ca. So does the right side
The Left side has 1 C. So does the right side.
The left side has 2 H. So does the right side
The left side has 2 oxygens (in Ca(OH2)) + 2 oxygens in CO2
So the equation is balanced.
Was is meant by the term suprenatural? Does science deal with the supernatural?
A. The term supernatural literally means (within nature) Science deals with the supernatural because it works within nature, not above it
B. The term supernatural literally means (above nature) Science does not deal with the supernatural because it works within nature, not above it
C. The term supernatural literally means (within nature) Science does not deal with the supernatural because it works above nature, not within it
D. The term supernatural literally means (above nature) Science deals with the supernatural because it also works with nature, not within it
Answer:
it's option D
I'll GIVE BRAINLIEST: In a redox reaction, CO is changed to CO2. How many electrons must be lost or gained by C and why?
Answer:
C is gaining 2 electrons
Explanation:
O has a 2- charge so for CO to pick up another O atom would add 2 more electrons.
Answer:
C gains 2 electrons
Explanation:
In the redox reaction, CO is changed into CO2 which means there is an additional oxygen. Oxygen loses 2 of its electrons in order to neutralize. So, C must be gaining 2 electrons in order to make the bond.
If a gas displays a solubility of 0.00290M at a partial pressure of 125 kPa, what is the proportionality constant for this gas in this solvent and at this temperature?
Answer:
The proportionality constant ( Henry’s constant) = 2.32 * 10^-5 M/kPa
Explanation:
Here in this question, we are concerned with calculating the proportionality constant for this gas.
Mathematically, we can get this from Henry law
From Henry law;
Concentration = Henry constant * partial pressure
Thus Henry constant = concentration/partial pressure
Henry constant = 0.00290 M/125 kPa = 2.32 * 10^-5 M/kPa
If the molarity of sugar is 1.1, what will the freezing point be?
Answer:
The freezing point will be -2.046°C.
Explanation:
The freezing point depression equation is [tex]\Delta T_f = k_f \cdot m \cdot i[/tex]
Where;
[tex]\Delta T_f[/tex] = The temperature depression of the freezing point
[tex]k_f[/tex]= The constant of freezing point depression which is solvent dependent = 1.86°C/m
i = The number of particles the substance decomposes into in solution = 1 for sugar (a covalent compound)
m = The molality of the solution = 1.1
Therefore, we have;
[tex]\Delta T_f = 1.86 \times 1.1 \times 1 = 2.046 ^{\circ}C[/tex]
Therefore the freezing point will be 0 - 2.046°C = -2.046°C.
Which of the following processes is exothermic? Group of answer choices Allowing meat to thaw after taking it out of the freezer Popsicle melting on a warm summer day Boiling water in a beaker to convert it to steam Rolling a ball up a hill Reacting hydrogen and oxygen gases to make water
Answer:
Reacting hydrogen and oxygen gases to make water
Explanation:
Exothermic means that energy is released into the environment, so let's go through the process of elimination.
Allowing meat to thaw after taking it out of the freezer - NO it is endothermic, and takes energy/heat from the environment to thaw.
Popsicle melting on a warm summer day - NO also endothermic, the opposite of exothermic.
Boiling water in a beaker to convert it to steam - NO because we need to add heat, so it doesn't release any energy.
Rolling a ball up a hill - NO, for a ball to roll up a hill, it needs energy from something else, so it's not exothermic.
Reacting hydrogen and oxygen gases to make water - YES this reaction makes new bonds, which releases energy, so this is exothermic.
Among the following choices reacting hydrogen and oxygen gases to make water is an exothermic reaction as it releases energy as new bonds are formed.
What is an exothermic reaction?An exothermic reaction is defined as a chemical reaction which involves release of energy in the form of light,heat .In these reactions, energy is transferred from system to surroundings rather than taking energy from surroundings into system as in endothermic reactions.
In an exothermic reaction,change in enthalpy is negative.Therefore, it can be inferred that net amount of energy which is required to start the exothermic reaction is less than the net amount which is released by the reaction.
Examples of exothermic reactions are combustion reactions, detonation of nitroglycerin , neutralization reactions and nuclear fission.
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Which bond type is found in ammonium chloride. Select one: a. metallic b. covalent c. ionic
Answer:
ionic
Explanation:
In NH4Cl molecule, ionic bond is formed between NH4+ and Cl– ions, 3 covalent bonds are formed between N and three H atoms and one coordinate bond is formed between N and 1 H atom.
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Answer:
[tex]\boxed{\sf c. \ ionic}[/tex]
Explanation:
NH₄Cl is formed by an ionic bond between NH₄⁺ and Cl⁻ ions.
NH₄Cl (solid) ⇒ NH4⁺ (aqueous) + Cl⁻ (aqueous)
What is the PRECAUTION for an Irritant?
You work in the special effects department of a movie studio. You are
currently working on a superhero movie where the hero is very strong
and can punch through metal. For the next scene you need to replace a
6 inch by 6 inch square of a metal wall with a different material that will
crumble when the actor hits it. What could you use?
A. You could use Carbon(C)
B. You could use Potassium (k)
C. You could use Titanium (T)
D. You could use Manganese (Mn)
Answer:
The correct option is;
D. Manganese (Mn)
Explanation:
Manganese is very brittle, hard, iron like silvery-gray metal, that is difficult to melt. In air, Manganese slowly disintegrate in a similar manner to iron rusting in water
Manganese and iron have similar chemical and physical properties however manganese is more harder and more brittle than iron
A brittle material is one that easily breaks without deforming elastically
Therefore, manganese, due to its very iron like appearance and brittle nature will be suitable to replace the metal wall and crumble easily when the actor hits it.
write the formula of three compounds which you know and name the elements in them
Answer:
[tex]\boxed{\sf{view \ explanation}}[/tex]
Explanation:
Compound definition:
A compound is a chemical substance formed by two or more chemically bonded elements.
Three compounds:
Water is a compound with the formula [tex]\sf H_2O[/tex].
Two hydrogen atoms and one oxygen atom is present in one molecule of water.
Sodium chloride or table salt is a compound with the formula [tex]\sf NaCl[/tex].
One sodium atom and one chlorine atom is present in one molecule of sodium chloride.
Ammonia is a compound with the formula [tex]\sf NH_3[/tex].
In one molecule of ammonia, one nitrogen atom and three hydrogen atoms are present.
Answer:
See below
Explanation:
Three compounds are:
1) [tex]\mathrm {H_{2}SO{4}}[/tex] [Sulfuric acid]
The elements in this compound are hydrogen (H) , Sulfur (S) and Oxygen (O).
2) [tex]\mathrm {NaOH}[/tex] [Sodium hydroxide]
The elements in this compound are Sodium (Na) , Oxygen (O) and Hydrogen (H).
3) [tex]\mathrm {HCl}[/tex] [Hydrochloric acid]
The elements are Hydrogen (H) and Chlorine (Cl).
List the metals Mg, Cu, Au, Na and Al in the decreasing order of their reactivity with air.
Answer:
Na is most reactiveAlcuAu is less reactiveIN HEREAnswer:
Potassium (K)
Sodium (Na)
Calcium (Ca)
Magnesium (Mg)
Aluminium (Al)
Iron (Fe)
Lead (Pb)
Copper (Cu)
Silver (Ag)
Gold (Au)
Lab Safety Rule #3 says to always add acids or bases to the solvent and NEVER the other way around true or false?
Answer:
true
Explanation:
The standard laboratory rule is to always add acids or bases to solvent and not the other way round.
The dissolution of concentrated acids/bases in solvents (water) generates heat energy. Thus, if the solvent is added to them, a layer of hot weak acid or base will be formed and this will boil and spray around, causing an explosion.
On the other hand, if acid/base is added to solvents, they flow into the solvents and get diluted immediately without any boiling taking place. Hence, it is safe to add acid/base to solvents and not the other way round.
It requires work to _____. A. stretch a spring only B. compress a spring only C. stretch or compress a spring
Answer:
C.
Explanation:
It requires work to stretch or compress a spring.
Answer:the answer is c
Explanation: i say that because with work you can do both of those things
If you are designing an experiment, how will you determine your independent or dependent variable?
Answer:
The independent variable effects the dependent variable.
Explanation:
The independent variable Is what you change whereas the dependent variable would change because of that.
for example, the indipendent variable could be how much you water a plant in ml each day, and the dependent variable would be how tall each plant grown]s with that water doseage per day.
Describe the reaction of an acid with an alkali.?
Your question has been heard loud and clear.
The reaction of an acid with an alkali is neutralization reaction. It is a neutralization reaction because , they both neutralize each other (means it makes them chemically inactive after reacting) and produce a salt , and maybe water too.
An example: hydrochloric acid + sodium hydroxide → sodium chloride + water
Thank you
it will neutralise because if you add both of them together with a matching Ph such as 5 and 9 equally then it will neutralise and have a Ph of 7
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Explanation:
The number of protons in the element C^12 (Carbon) is 6, number of electrons 12 and number of Neutrons is 6, same as the number of protons it contains
C^13 has 13 electrons, 6 protons and 7 Neutrons this one's neutron number is different from proton number because it's an isotope
Na^-1 has gained an electron so the number of electrons it has = 24 and the number of protons shown as 11 which means there are 23 - 11 = 12 Neutrons
O^-2 has gained two electrons and got 18 electrons in total, 8 protons and 8 neutrons
The number of atoms in 2.0 moles of NaOH is _____ of 1.0 mole of H2O.
twice that
less than
more than
the same as
Answer:
The answer is the same as .
Explanation:
There are 3 atoms in NaOH, 1 sodium, 1 oxygen and 1 hydrogen.
There are 3 atoms in H2O, 2 hydrogen and 1 oxygen.
What would be the pH of an HNO3 solution if the [H+] = 3.26 x 10-6 moles/liter? 5.49 4.67 6.32
Answer:
5.49
Explanation:
pH = - log[3.26 x 10-6] =5.49
Explain the different between a molecule and a compound.
Answer:
-A molecule is the smallesr part is compound whereas a compound is the combination of two or more atoms in a fixed proportion by wiehgt.
- A glass of water is an example of compound but a small portion of water can be called molecule.
Levi decides to examine the effect of fertilizer on the growth of tomato plants. He chooses four plants for his experiment and applies varying amounts of fertilizer to three of them. He does not apply fertilizer to one plant. Over a 15-day period, the plants receive fertilizer on Days 1, 4, 7, 10, and 13. Levi measures the height of all of his plants with a meter stick on days 3, 6, 9, 12, and 15. He also makes sure to hold all experimental factors constant except for the fertilizer.
Where should the independent and dependent variables of Levi's experiment be placed when graphed?
Select all that apply.
the amount of fertilizer;y-axis
plant height;x-axis
the amount of fertilizer;x-axis
plant height; y-axis
Answer:
the amount of fertilizer; x-axis
plant height; y-axis
Explanation:
The independent and dependent variables of Levi's experiment placed when graphed are the amount of fertilizer and the y-axis. Option B is correct.
What are independent and dependent variables?The independent variables are those which are not dependent on other factors for their working or cannot be influenced by any other factor and the dependent variable is just the opposite of this one.
The experiment depends on the height of the plant but the fertilizer is independent of to work of the plant and fertilizer is independent and high and depends on other factors.
Therefore, Option B is correct. independent and dependent variables of Levi's experiment placed when graphed are the amount of fertilizer and the y-axis.
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