You can use the scientific method everyday by asking questions and doing experiments. For example, you want to know how a fire starts, so you do an experiment with it!
Balance the following equation. Choose "blank" if no coefficient other than 1 is needed. CaCl2 + Na2CO3 CaCO3 + NaCl
Answer:
Hi there!!!
The answer is given in picture.
In question we had 2 sodium(Na) and chlorine (cl) but after reaction nacl donot contain it. so, we need to put 2 infront of nacl to make them equal.
As balancing chemical equation refers to the process of keeping or making equal to the atoms of both product and reactant.
Hope it helps..
The identity of an element is determined by
A. the number of neutrons
B. the weight of the nucleus
C. the number of protons
D. the number of electrons
The answer is Number of Protons !
Answer: D. the number of protons
Explanation: The number of protons shows you what the Atomic number of an element is on the Periodic table of elements.
The identity of an element is primarily determined by the number of protons it possesses. The Option C.
What determines the identity of an element?Each element on the periodic table has a unique number of protons in its nucleus which is referred to as its atomic number. This fundamental property of an element distinguishes it from other elements and determines its place on the periodic table.
While number of neutrons and electrons can vary within an element, it is the number of protons that defines its identity. Thus, the correct answer is C: the number of protons.
Read more about element identity
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Complete this sentence. If mass remains the same while the volume of a substance ________, the density of the substance will_______________.
Answer:
If mass remains the same while the volume of a substance changes, the density of the substance will also change.
Answer:
BELOW
Explanation:
If mass remains the same while the volume of a substance decreases the density of the substance will increase.
please someone explain this I dont get it at all. how do we know that the 4th electron came from 2p because it's at 4th ionisation? why is it talking about 3s?? how do overall know that aluminium is in group 3 from the table??? thanks
What is the colour formed when N2O is bubbled into a solution of acidified FeSO4
Define physical and chemical properties, provide three examples of each, discuss their reversibility, and explain the fundamental differences between them.
Answer:
Physical properties are defined as the properties which can be observed without changing its chemical composition.
For example: color, volume, and molecular weight.
Chemical properties are defined as the properties which can be observed only after changing chemical identity of the substance.
For example: reactivity, toxicity, and flammability.
The fundamental differences between physical and chemical properties are as follows:
Chemical properties are related to chemical bonds of the substance while physical properties are not.In chemical properties, chemical identity of substance changes while physical properties do not have any change.Chemical properties predict the reaction of substance while physical properties only describe the appearance of the substance.
Answer:
Chemical properties are related to chemical bonds of the substance while physical properties are not.
In chemical properties, chemical identity of substance changes while physical properties do not have any change.
Chemical properties predict the reaction of substance while physical properties only describe the appearance of the substance.
Explanation:
explain why ply(ethene) can become a pollutant?
Answer:
ipotseeeeeeeeeeeeeeee
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:
The term supernatural literally means, Science does not deal with the supernatural because within nature, not within it
Air is an example of a mixture because the elements and compounds that make up air retain their individual properties. T or F
Answer:
True
Explanation:
This is true because no chemical bonding or change was involved only mechanical mixing.
The recommended dose of aminophylline for children is 1.0 mg/kg/hr. 15 mL of a 30 mg/mL sltn is added to a 150 mL bottle of D5W. At what rate mL/hr should the injection be delivered to 35 lb child
Answer:
The answer is "6.68 [tex]\frac{ml} {hr}[/tex]".
Explanation:
It's going to be 18.18 kg to turn body mass to kg.
Size 1mg / kg / hr, therefore = 1 x 18.18
= 18.18 kg / hr
now we adding 30 mg / ml of dextrose = 30 x 15
[tex]=\frac{450mg}{15 ml +150 ml}[/tex]
of dextrose, from 15 ml to 150 ml;
Therefore, now 450 mg in 165m:
[tex]= \frac{ 450}{165}\\ \\=2.72 \frac{mg} {ml}[/tex]
now divide the 18.18 by 2.72:
[tex]=\frac{18.18}{2.72}[/tex]
= 6.68 [tex]\frac{ml} {hr}[/tex]
Di- Ethyl zinc is a chemical used in the library to protect books from worms, its composition is 53% Zinc, 38.9% Carbon, and 8.1% Hydrogen (At mass of Zn=65.4, C=12, H=1). Find the empirical formula of a compound
Answer:
ZnC4H10
Explanation:
The empirical formula of a compound refers to the formula that gives the simplest whole number ratio of each atoms of the elements in the compound.
The empirical formula is calculated thus:
The given percentages in the question represent the mass in grams of each element in the compound.
Zinc= 53%, C= 38.9%, H= 8.1% which represents 53g, 38.9g and 8.1g of each element respectively.
Molar Mass of Zn= 65.4 g/mol
Molar Mass of C= 12 g/mol
Molar Mass of H= 1 g/mol
Step 1: Divide the mass of each element by the molar mass given to convert to moles:
Zn= 53/65.4 = 0.81moles
C= 38.9/12 = 3.24moles
H= 8.1/1 = 8.1moles
Step 2: Divide each mole value by the smallest number of moles calculated, which is 0.81moles:
Zn= 0.81/0.81 = 1
C= 3.24/0.81 = 4
H= 8.1/0.81= 10
This is the mole ratio represented in the subscript of each element in the empirical formula:
That is, Zn (1) C (4) H (10)
Empirical formula= ZnC4H10
what is mean by stakeholder
Answer:
a stakeholder is a party that has an interest in a company and can either effect or be affected by the business. the primary stakeholder in a typical corporation are its investors , employees, customers and supplies.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.
Learn more about exothermic reactions,here:
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Perform the forlowing
mathematical operation, and
report the answer to the correct
number of significant figures.
4568/13 = [?]
Answer:
[tex]\large \boxed{350}[/tex]
Explanation:
In multiplication and division problems, the answer can have no more significant figures than the number with the fewest significant figures.
My calculator gives the result:
[tex]\dfrac{4568}{13} = 351.3846154[/tex]
4658 has four significant figures.
13 has two significant figures.
You must round to two significant figures.
That is, you drop all the digits to the right of the 5 — the red line in Fig. 1 below. You are rounding to the nearest ten.
To round a number to the nearest ten, you look at the number in the ones place (1). See Fig. 2.
If the number to be dropped — the digit in the ones place — is less than 5, you drop the digit in the ones place (Fig. 3). It becomes a zero.
The number in the tens place is a trailing zero. It is not significant.
[tex]\text{The quotient of $\dfrac{4658}{13}$ is $\large \boxed{\mathbf{350}}$}[/tex]
percentage of carbon in urea
The percentage of carbon in urea is [CO(NH 2) 2] is 20%
explain the formation of coke?
please answer this question
I will mark u the brainlest☺️☺️
Answer:
Here is it....
Explanation:
What is the atomic number of neon?
Answer:
the atomic number of a neon is 10
The density of a 39 gram object with a volume of 5 cm is
Answer:
[tex]\huge\boxed{\sf D = 7.8 \ g/cm^3}[/tex]
Explanation:
Density = Mass / Volume
Where Mass = 39 g and Volume = 5 cm³
So,
[tex]\sf Density = \frac{39}{5} \\Density = 7.8 g/cm^3[/tex]
Please help me...
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.
Hope this is OK :))
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3.87 moles of iron bromide yielded10.4 moles of sodium bromide
Answer: 89.57 %
Hope it helps
4 examples of ionic bonding identifying in each one the anion, the cation and demonstrate the ionic bonding by means of the electronegativity difference.
Answer:
Here are some examples
Explanation:
NaCl
Cation = Na⁺, Anion = Cl⁻; ΔEN = |0.93 - 3.16| = 2.23
MgS
Cation = Mg²⁺, Anion = O²⁻; ΔEN = |1.31 - 3.44| = 2.53
KBr
Cation = K⁺, Anion = Br⁻; ΔEN = |0.82 - 2.96| = 2.14
CaF₂
Cation = Ca²⁺, Anion = F⁻; ΔEN = |1.00 - 3.98| = 2.98
In each case, ΔEN > 1.6, so the compound is ionic.
If a chemist wants to make one liter of a 1.5 M solution of NaOH from a stock solution of 2.5 M NaOH, how many milliliters of the stock solution would the chemist need to use?
A.6.0 x 102 mL
B. 0.60 mL
C. 1.7 x 103 mL
Answer:
0.60 mL
Explanation:
1. Set up the equation using Vi = MfVf / Mi
Vi = (1.5M · 1L) / 2.5M
2. Solve
1.5 / 2.5 = 0.6
How would a decrease in volume affect the following reaction? N2 (g) + O2 (g) Two arrows stacked on top of each other. The top arrow points to the right. The bottom arrow points to the left. 2NO(g) (1 point) The equilibrium would shift to the right. The equilibrium would shift to the left. There would be no change to equilibrium. The affect on equilibrium cannot be determined.
Answer:
Explanation:
N₂(g) + O₂(g) ⇄ 2NO( g )
We shall apply Le Chatelier's principle to see the effect of decrease in volume or increase in concentration on the effect of state of equilibrium in the reaction given .
In this reaction 1 volume of nitrogen gas reacts with 1 volume of oxygen to give 2 volume of NO gas . In total there is no change in volume due to reaction . So when we change the volume , the concentration of reactant and product will affect the rate of forward and reverse reaction . Overall there will be no change in the state of equilibrium . The equilibrium will neither shift to the right nor will shift to the left.
It will remain unchanged .
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
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How do scientists use ice to study ancient climates?
A. through glacial deposits and ice cores
B. through glacial deposits and ice ages
C. through ice cores and pollen grains
D. through pollen grains and ice ages
Which greenhouse gas is produced by commercial refrigeration and air conditioning systems?
A. carbon dioxide
B. fluorinated gas
C. nitrous oxide
D. methane
Explanation:
the first question's answer is a
the second question's answer is c
Question #13
What causes the low pressure zones around the equator?
Hint: How does air move at a low pressure zone? Why does
air move that way? What happens at the equator that would
cause air to move that way?
Answer:
Warm equatorial air rises higher into the atmosphere and migrates toward the poles. This is a low-pressure system. At the same time, cooler, denser air moves over Earth's surface toward the Equator to replace the heated air. ... This happens because Earth's rotation generates what is known as the Coriolis effect
Which of the following polyatomic ions will form an ionic compound with two sodium ions? CO32− HCO31− NO21− NO31−
Answer:
CO32−
Explanation:
We have to consider the valencies of the polyatomic ions involved. Recall that it is only a polyatomic ion with a valency of -2 that can form a compound which requires two sodium ions.
When we look closely at the options, we will realize that among all the options, only CO32− has a valency of -2, hence it must be the required answer. In order to be double sure, we put down the ionic reaction equation as follows;
2Na^+(aq) + CO3^2-(aq) ---------> Na2CO3(aq)
Answer:
A). CO32−
Explanation:
using methyl ,phenolphthalein and litmus name an acid
Answer:
These are two types of indicators which show a solution is either an acid a natural or an alkali solution
Explanation:
Hope this helps :)
calculate the amount in moles of a gas which occupies 250cm3 at s.t.p
Answer: 0.01 moles (I am guessing)
Explanation:
Firstly, cm3 and ml are equal to one another, therefore 250cm3 can also be written as 250 ml. I Googled and found that ideally, one mole of gas will occupy a volume of 22.4 L (22,400 ml) at s.t.p. 250 ml out of 22,400 ml is 0.01 rounded, therefore I assume that is the answer. About 0.01 mole occupies 250 cm3 at s.t.p.
Using complete sentences, explain how to predict the products and balance the reaction between sulfuric acid and potassium hydroxide. H2SO4 + KOH ⟶
Answer:
The answer to your question is given below.
Explanation:
The reaction of sulfuric acid and potassium hydroxide is called neutralisation.
Neutralisation is a reaction involving an acid and a base which produces salt and water only.
For the react between sulfuric acid, H2SO4 and potassium hydroxide, KOH, we can predict the products obtained as follow:
H2SO4 + KOH —>
In solution, H2SO4 and KOH will dissociate as follow:
H2SO4(aq) —> 2H^+(aq) + SO4^2-(aq)
KOH(aq) —> K^+(aq) + OH^-(aq)
H2SO4 + KOH —>
2H^+(aq) + SO4^2-(aq) + K^+(aq) + OH^-(aq) —> K^+(aq) + SO4^2-(aq) + 2H^+(aq) + OH^-
H2SO4 + KOH —> K2SO4 + H2O
Now, we can balance the above equation as follow:
H2SO4 + KOH —> K2SO4 + H2O
There are 2 atoms K on right side and 1 atom on the left side. It can be balance by writing 2 in front of ko as shown below:
H2SO4 + 2KOH —> K2SO4 + H2O
There are 2 atoms of H on the right side and a total of 4 atoms on the left side. It can be balance by writing 2 in front of H2O as shown below:
H2SO4 + 2KOH —> K2SO4 + 2H2O
Now,the equation is balanced.
Answer:
Given the reactants, H2SO4 and KOH, we are asked to determine the product(s) of the reaction. Since H2SO4 is an acid and KOH is a base. This is a neutralization reaction, thus, the products are salt and water.
So, H+ from H2SO4 will react with OH- from KOH forming H2O. K+ will also react with SO4 2- forming K2SO4. Therefore, the balanced reaction will be:
H2SO4 + 2KOH ---> K2SO4 + 2H2O
Explanation: