Answer:
Because as we move down the group size/ radius of atom increases due to increase in shells and screening effect. The hold of nucleus on valence electrons decreases and effective nuclear charge decreases so it is easy to remove electron from greater sized atoms as compared to smaller sized aroms.
Energy required to remove electron is ionization energy so greater sized atoms have low ionization energy.
Explanation:
The temperature of a 9.0 g sample of glass changed from 20 to 50 when it absorbed 680 J of heat. What is the specific heat of this glass sample?
Answer:2518.5J/kg/K
Explanation:
Who do you think we (humans) are more related to bats, or chickens?
Answer:
prolly chickens
One characteristic that salt water and sugar-water have in common is, at room temperature, they are
a)gases
b)solids
c)mixtures
d)elements
Answer:
The one thing they have in common is that They are mixtures
Answer:
they are both mixtures
Explanation:
Which of the following elements has the highest atomic radius, Sr or Cu
Answer:
Sr or Strontium
Explanation:
sr: strontium has atomic radius of 255pm
cu: copper has an atomic radius of 128pm
they teach you in chem how to do it based off the chart but I don't remember that method
Which force saves the atom by emitting particles from the nucleus
Answer:
nuclear force
Explanation:
Sarah wants to know where in her garden chamomile would grow the best. She thinks chamomile will grow best in the corner of the garden that gets the most sunlight. To test her hypothesis, she decides to plant several groups of chamomile in her garden as an experiment.
Answer:
This question is incomplete and lacks options, the complete part and the options are:
Which of the following variables should Sarah change from one group of chamomile to the next?
A. the location of the plants
B. the height of the plants
C. the type of plants
D. the amount of water she gives the plants
The answer is A
Explanation:
This question is asking for the INDEPENDENT VARIABLE in the experiment. The independent variable of an experiment is the variable that is changed or manipulated by the experimenter in order to bring about a response.
In this experiment where Sarah wants to know where in her garden chamomile plants would grow the best. She hypothesizes that chamomile will grow best in the corner of the garden that gets the most sunlight. However, to test this hypothesis, she decides to plant several groups of chamomile in her garden as an experiment. The variable that Sarah can change in the several groups of chamomile (independent variable) is the LOCATION OF THE PLANTS.
Note that, "where" is a question of location.
Answer:
The answer is C
Explanation:
2. How many moles are found in 3.2 x 1023 atoms of NaCl?
Answer:
0.53 mol NaCl
General Formulas and Concepts:
Chemistry - Atomic Structure
Using Dimensional AnalysisAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Explanation:
Step 1: Define
3.2 × 10²³ atoms NaCl
Step 2: Identify Conversions
Avogadro's number
Step 3: Convert
[tex]3.2 \cdot 10^{23} \ atoms \ NaCl(\frac{1 \ mol \ NaCl}{6.022 \cdot 10^{23} \ atoms \ NaCl} )[/tex] = 0.531385 mol NaCl
Step 4: Check
We are given 2 sig figs. Follow sig fig rules and round.
0.531385 mol NaCl ≈ 0.53 mol NaCl
What historical event of commercial interest triggered investigation in the science of steam?
Answer: Photosynthesis
Explanation:
Which value indicate the strongest base
A. pH of 2
B. pH of 5
C. ph of 12
D. pH of 8
Explanation:
The highest number is the strongest base. Therefore the pH of 12 is the strongest base here (C).
Identify the source of energy in a chemical reaction.
The temperature of an object is directly related to
A.
the mass of the object.
B.
the motion of its particles.
C.
the potential energy of its chemical bonds.
D.
the volume of the object.
Answer:B
Explanation:Because when the object heats up the particles move faster and it will turn into a liquid or gas but if it is being cooled then the particles will slow down and either make a liquid or solid.
Of the elements Pt, V, Li, and Kr, which is a nonmetal?
Which of the following statements about energy is NOT TRUE?
O Energy is the ability to do work or cause change.
Energy can neither be created nor destroyed.
When you use energy, the total amount of energy decreases.
Energy can be changed from one form to another.
Answer:
when you use energy , the total amount of energy decreases.
What is the volume of 2 moles of He at STP?
Answer:
STP conditions imply a temperature of 273.15 K and a pressure of 100 kPa. When tose conditions are met, 1 mole of any ideal gas will have a volume of 22.7 L. So, if 1 mole occupies a volume of 22.7 L, 2 moles will occupy a volume twice as big. Likewise, 0.5 moles will occupy half the volume 1 mole occupies. Assuming that the gas is at standard temperature and pressure (STP), one mole of any gas occupies 22.4 L . This means the number of moles of O2 is 222.4=0.089 mol .
Explanation:
The SI unit for length is?
Answer:
Metre
Explanation:
the SI unit of length is Metre
Answer:
The SI unit for length is Meter
. Now Sara comes along, and she is the exact same size as you. However, she is even stronger than you are! When she pulls you in the wagon, she pulls with a greater force than when you pull her. Now who is in the wagon when it has the greatest acceleration? Explain, using Newton's second law. Sara would win because she is stronger but we have the same force.
Answer:
See explanation
Explanation:
According to Newton's second law, the rate of change of momentum is proportional to the impressed force.
Mathematically;
Ft = mv - mu
Where;
F = Force
t = time
m= mass
v = final velocity
u = initial velocity
Since the mass is the same, the equation reduces to;
Ft = m(v-u)
So
F= m(v-u)/t
but
(v-u)/t = acceleration (a)
F = ma
a = F/m
Since the mass is the same because Sarah is the same size as i am but she pulls with a greater force, it follows that i will be the one in the wagon when the wagon has the greatest acceleration because the force that Sarah applies when pulling me is greater than the force i will apply when pulling her.
What would you observe in the following cases:
(1) Sodium and potassium are placed in hot water
(ii) Burning magnesium is introduced into steam?
dium and iron with water
Answer:
See explanation
Explanation:
When introduced to hot water, sodium and potassium metals react violently to form a colourless solution and hydrogen gas. The metal becomes spontaneously ignited and burns with its characteristic flame colour.
Magnesium burns with a bright white flame to yield solid magnesium oxide
and hydrogen gas when steam is passed over heated magnesium.
The last question is not clear but I believe that it has to do with reaction of sodium and iron with water. Sodium reacts violently with cold water at room temperature to evolve hydrogen gas and aqueous sodium hydroxide.
Iron reacts with steam at red heat to yield hydrogen gas and Fe3O4
(0)A mixture of dihydrogen and dioxygen at one bar pressure contains 70% by weight of dioxygen. Calculate the partial pressure of dioxygen.
a (ii)Calculate the volume occupied by 8.8 g of CO2 at 31.1°C and 1 bar pressure. R = 0.083 bar L K-1 mol-1
Answer:
a) 0.13 bar
b) 5.05 L
Explanation:
Let us take the mass of the mixture to be 100 g. Hence, 70% by weight of dioxygen corresponds to 70 g
Mass of dihydrogen = 100g - 70 g = 30g
Number of moles of dioxygen = 70g/32 g/mol = 2.2 moles of dioxygen
Number of moles of dihydrogen = 30g/2g/mol = 15 moles of dihydrogen
Total number of moles = 2.2 + 15 = 17.2 moles
Mole fraction of dioxygen = 2.2/17.2 = 0.13
Partial pressure = mole fraction * total pressure
Partial pressure of dioxygen = 0.13 * 1 = 0.13 bar
ii) number of moles in 8.8 g of CO2 = 8.8g/44g/mol = 0.2 moles
T = 31.1 + 273 = 304.1 K
P = 1 bar
V= ?
R = 0.083 bar L K-1 mol-1
From
PV=nRT
V = nRT/P
V= 0.2 * 0.083 * 304.1/1
V= 5.05 L
A 0.85% saline solution is: a.8.5 mL of saline added to 91.5 mL of water b.85 g of NaCl made up to 1,000 mL of water c.0.85 g NaCl made up to 100 mL of water d.8.5 g NaCl in 100 mL of water
Answer:
c
Explanation:
A 0.85% saline solution would consist of 0.85 g NaCl made up to 100 mL of water.
A 0.85% saline solution contains 0.85% by weight of NaCl. Hence, in order to prepare such a solution, 0.85 g of NaCl is weighed out into a beaker or cylinder and distilled water is added up to the 100 mL mark. On the other hand, 8.5 g of the NaCl can be weighed out and then distilled water added to 1000 mL mark.
The correct option is, therefore, c.
Explain why PCI5 can be formed whereas
PI5 cannot be formed.
Answer:
highly unstable
Explanation:
also, due to repulsion of lone pairs and instability it breaks and can't form PI5
hope that helps....
Consider the following balanced equation:
P4(s) + 6F2(e)
4PF3(g)
If 1.25 moles of P4(s) is reacted with 6 moles of F2(g), How many moles of PF3(e) are
produced?
O 5 moles
4 moles
O 6 moles
O 3 moles
Moles of PF₃ : 4
Further explanationA reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reagents and products.
Reaction
[tex]\tt P_4(s)+6F_2(g)\rightarrow 4PF_3(g)[/tex]
1.25 moles of P₄(s) is reacted with 6 moles of F₂(g)
Limiting reactant : the smallest ratio (mol divide by coefficient)
P₄ : F₂ =
[tex]\tt \dfrac{1.25}{1}\div \dfrac{6}{6}=1.25\div 1\rightarrow F_2~limiting~reactant(smallest~ratio)[/tex]
mol PF₃ based on mol of limiting reactant(F₂), so mol PF₃ :
[tex]\tt \dfrac{4}{6}\times 6~moles=4~moles[/tex]
One isotope of a nonmetallic element has mass num- ber 127 and 74 neutrons in the nucleus. The anion derived from the isotope has 54 electrons. Write the symbol for this anion.
Answer:
I⁻
Explanation:
The identity of the element is obtained when the proton number is known.
Mass Number = 127
Neutrons = 74
Number of protons is obtained from;
Protons = Mass Number - Number of Neutrons
Protons = 127 - 74 = 53
The element is Iodine and it's symbol is I.
However, The anion derived from the isotope has 54 electrons
A neutral Iodine should have 53 electrons. This means it has gained a single electron. The symbol is now written as;
I⁻
How many moles are there in 1.68 * 10 ^ 24 molecules of nitrogen dioxide?
Answer:
2.79 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\[/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
[tex]n = \frac{1.68 \times {10}^{24} }{6.02 \times {10}^{23} } \\ = 2.790697 ...[/tex]
We have the final answer as
2.79 molesHope this helps you
which statements are wrong about atoms
Answer: Atoms are not able to exist independently
Explanation:
look.............................................
Answer:
Your answer is correct.
Explanation:
The steel paper clip would only move because it has steel in it, which is a magnetized material, plastic on the other side, is made up of polymers which are not attracted to the magnetic force, causing it not to move.
Haley is trying to pull an object upward. The below forces are acting on the object.
Fp= 5500 N
Fg= 6000 N
Which represents the net force?
← 500 N
→ 500 N
↑ 500 N
↓ 500 N
Explanation:
it's answer is last
hope it helps you
↓ 500 N represents the net force as the force is acting in downward direction.
What is force?
Force is defined as a cause which is capable of changing the motion of an object. It can cause an object which has mass to change it's velocity. It is also simply a push or a pull . It has both magnitude as well as direction.Hence, it is a vector quantity.
It has SI units of Newton and is represented by'F'.Newton's second law states that force which acts on an object is equal to momentum which changes with time. If mass of object is constant, acceleration is directly proportional to net force acting on an object.
The concepts which related to force are thrust and torque .Thrust increases the velocity of an object and torque produces change in rotational speed of an object.
Learn more about force,here:
https://brainly.com/question/30507236
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The initial temperature of a bomb calorimeter is 28.50°C. When a chemist carries out a reaction in this calorimeter, its temperature decreases to 27.45°C. If the calorimeter has a mass of 1.400 kg and a specific heat of 3.52 J/(gi°C), how much heat is absorbed by the reaction?
Use q equals m C subscript p Delta T..
140 J
418 J
1,470 J
5,170 J
Answer:
The correct answer is 5,170 J
Explanation:
The heat absorbed by the reaction (Qr) is equal to the heat released by the calorimeter (Qcal):
Qr = - Qcal
We calculate Qcal from the mass of the calorimeter (m), the specific heat (Cp), and the change in temperature (ΔT), as follows::
Qcal = m x Cp x ΔT
We have the following data:
m = 1.400 kg x 1000 g/1 kg = 1,400 g
Cp = 3.52 J/g°C
Initial T = 28.50°C + 273 = 301.50 K
Final T = 27.45°C + 273 = 300.45 K
ΔT = Final T - Initial T = 300.45 K - 301.50 K = -1.05 K
So, we introduce the data in the mathematical expression for Qcal:
Qcal = m x Cp x ΔT = 1,400 g x 3.52 J/g°C x (-1.05 K) = -5,174.4 J ≅ -5,170 J
Therefore, the heat absorbed by the reaction is:
Qr = - Qcal = -(-5,170 J) = 5,170 J
Answer:
D
Explanation:
Just took the test.
Write the name of the covalent compound ON.
Answer:
the answer is oxygen mononitride
Write True/False against the following statements and also correct the false statement.
Greater the calorific value better is the fuel.
Answer:
I think it is true you should go for true
How many neutrons are present in an atom of