Answer:
Metal
Element: Calcium
Valency: 2
Explanation:
To find the element, let's use the periodic table. (Look below)
We already went past 3 shells, just need the 2 electrons after it.
Just skip to the 4th row and count 2 to the right
We end up at Calcium.
Calcium is a metal and we're also on the alkaline earth metals column.
Calcium will need to lose 2 electrons to reach stability, so the valency is 2.
Energy in the amount of 420 J is added to a 35 g sample of water at a temperature of 10°C. What is the final temperature of the water?
The final temperature of the water, T2 = 38.57°C
Temperature can be defined as a measure of the degree of hotness or coldness of a physical object (body). Thus, it is measured with a thermometer and its units are degree Celsius (°C), Fahrenheit (°F) and Kelvin (°K).
A calorie refers to the amount of heat required to raise the temperature of a gram of water by one (1) degree Celsius (1°C).
Given the following data:
Quantity of energy = 420JMass = 35 gramsInitial temperature, T1 = 10°CThe specific heat capacity of water is 4.2 J/g°C.
To find the final temperature of the water (T2):
Mathematically, the quantity of energy (heat capacity) is given by the formula;
[tex]Q = mcdt[/tex]
Where;
Q represents the heat capacity or quantity of heat.M represents the mass of an object.C represents the specific heat capacity of water.dt represents the change in temperature.Substituting the values into the formula, we have;
[tex]420 = 3.5 \; * \; 4.2 \; * \; dt[/tex]
[tex]420 = 14.7 \; * \; dt\\\\dt = \frac{420}{14.7}[/tex]
Change in temperature, dt = 28.57°C
Next, we would solve for the final temperature by using this formula;
[tex]dt = T2 - T1[/tex]
[tex]28.57 = T_{2} - 10\\\\T_{2} = 28.57 \; + \; 10\\\\T_{2} = 38.57[/tex]
Final temperature, T2 = 38.57°C
Therefore, the final temperature of the water, T2 is equal to 38.57°C
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Which of the following is the best definition of a physical property?
A. Tearing paper in half.
B. Something that can be observed or measured while changing the identity of the substance.
C. The ability of something to undergo a change or reaction.
D. Something that can be observed or measured without changing the identity of the substance.
Answer:
D.Something that can be observed or measured without changing the identity of the substance.
in order to decrease the freezing point of 500. g of water to 1.00° c how many grams of ethylene glycol (C2H602)must be added (KF=1.86°C kg solvent)
Answer:
if wrong sorry ok????
What does the prefix trans-indicate?
A. There are at least two double bonds in the molecule.
B. The carbons on either side of the double bond are pointed in
opposite directions.
C. The molecule is an alkane with no double bonds.
O D. The carbons on either side of the double bond are pointed in the
same direction
Answer:
B. The carbons on either side of the double bond are Pointed in opposite directions
why water can reduce unpleasant smell that produce from methane gas ?
Answer:Water contains Oxygen the purified the methane gas
Explanation:
Using your answers from part C, complete the chemical formula of each compound. If the number of ions is 1, leave that
number out of the formula.
Drag each number to the correct location. Numbers may be used more than once
Answer:
1;1, 2;1, 3;1, 1;2, 1;1, 3;2, 1;3, 2;3, 1;1.
I hope this will help.
Answer:
This is what the answer looks like
Explanation:
1 atm is equal to
O 1 mmHg
• 14.7 mmHg
• 76 mmHg
© 760 mmHg
Answer:
C 760 mm of hg
because this is the atmospheric pressure at sea level
are standard electrode potential and standard hydrogen potential same?
Answer:
Potentials of any other electrodes are compared with that of the standard hydrogen electrode at the same temperature. Hydrogen electrode is based on the redox half cell: 2 H+(aq) + 2 e− → H2(g)..
If 16.4 grams of calcium nitrate is heated as shown in the reaction:
2Ca(NO3)2 -> 2CaO + 4NO2 + O2.
Calculate the volume of nitrogen dioxide produced at STP.
Answer:
7.2
Explanation:
you first have to find the number of moles of nitrogen dioxide by using the number of moles for calcium nitrate and the mole to mole ratios
number of moles of calcium nitrate=mass/mm
=16.4/102
=0.16g/mol
then you use the mole to mole ratios
2 : 4
0.16: x
2x/2=0.64/2
x=0.32g/moles of nitrogen dioxide
then you use the formula for the volume
v=22.4n
=22.4×0.32
=7.2
I hope this helps
Which sentence describes existing cells?
All cells, once formed, continue to live forever.
All cells come from previously existing cells.
All the cells that are on Earth have always been here.
All cells develop from the remains of other cells.
what apparatus is used to investigate the conductivity of solutions
True or false, The four units that must always be used when using the ideal gas are 44.0 liters
Answer:
for volume only liters can be used
Explanation:
write an importance of endothermic reactions
Answer:
the uses of exothermic reactions are:
1) lighting of stove
2) self heating cans
3) hand warmers
4) in some case exothermic process can be used to cook food such as rice (by adding calcium oxide to water heat is evolved and it helps to cook food )
Explanation:
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Which equation describes a physical change? i. H2O(s) ⟶ H2O(l) ii. Na+(aq)+Cl−(aq) +Ag+(aq)+NO3−(aq) ⟶ AgCl(s)+Na+(aq)+NO3−(aq) iii. CH3OH(g)+O2(g) ⟶ CO2(g)+H2O(g) iv. 2H2O(l) ⟶ 2H2(g)+O2(g) v. H+(aq)+OH−(aq)⟶ H2O(l)
Answer:
The answer is "Option i"
Explanation:
In this question, only option (i) is correct, and others were wrong which can be defined as follows:
In option (ii):
[tex]Na^+\ (aq)+Cl^- \ (aq) +Ag^+ \ (aq)+NO_3^- \ (aq) \to AgCl\ (s)+Na^+ \ (aq)+NO_3^-\ (aq) \\\\[/tex]
It is the complete ionic equation.
In option (iii):
[tex]CH_3OH\ (g)+O_2\ (g) \to CO_2\ (g)+H_2O\ (g)[/tex]
It is the combustion reaction but a not balanced equation.
In option (iv):
[tex]2H_2O\ (l) \to 2H_2\ (g)+O_2\ (g)[/tex]
It is the decomposition equation.
In option (v):
[tex]H^+\ (aq) +OH^-\ (aq)\to H_2O\ (l)[/tex]
It is the complete ionic equation.
Which of the following molecules contains six bonding electrons?
A C2H4
B CO2
C H2S
D NCl3
Answer:
c2h4 (etthane........
bexcuse it has 6 bond of hydrogen
C₂H₄ molecules contains six bonding electrons. Therefore, option A is correct.
What do you mean by the term bonding ?Chemical bonding is the process through which two or more atoms, molecules, or ions establish a chemical link to create a chemical compound. The atoms in the resultant molecule are held together by these chemical bonds.
Chemical bonds have three basic characteristics that must be taken into account: their strength, length, and polarity. The distribution of electrical charge among the atoms connected by a bond determines its polarity.
C₂H₄ molecules has six bonding electrons. This molecule is called as Ethylene. When bonding is done between two atoms, each atom shares a pair of electrons with each other.
Hence, for every one bond, two electrons are shared between two atoms
Thus, option A is correct.
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what is a cubic unit cell ?
cubic unit cell is the smallest repeated unit which have all angles equal to 90 and all have edge lengths equal
It is the type of the Unit cell which is having all angles equal to 90 and all sides equal to each other
it's is a unit cell with cubic structure
Please help with the Volume one
Answer:
im a just achild
Explanation:
Answer:
c
Explanation:
0.5dm³
follow me if you want
Can you help me on this. I will support your correct answer
difference between Nitrogen 1 oxide and Oxygen
Answer:
one atom of oxygen is not equal to oxygen
Cho các dung dịch: Glucozơ, glixerol, fomanđehit, etanol. Có thể dùng thuốc thử nào sau đây để phân biệt được cả 4 dung dịch trên?
A. Cu(OH)2; B. Dung dịch AgNO3 trong NH3;
C. Na kim loại; D. Nước brom.
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Answer:
chắc là câu B í
Explanation:
A sample of gas has a volume of 20 cm³.The pressure is changed to 90 kPa at constant temperature,while the volume increases to 75 cm³.What was the original pressure of the gas?
Answer:
337.5kPa ~ 338kPa
Explanation:
Using the ideal gas law PV=nRT we have the following definitions from the problem:
V(initial) = 20cm³
P(initial) = ?kPa
V(final) = 75cm³
P(final) = 90kPa
Since we know that the number of moles of the sample did not change, nor did the temperature, nor does the ideal gas constant (R) we can rewrite this equation to state:
P(initial)V(initial) = nRT =P(final)V(final) ~ P(initial)V(initial) = P(final)V(final)
Rearranging this equation as we are solving for the initial pressure we find that:
P(initial) = (P(final)V(final))/V(initial)
P(initial) = ((90kPa)(75cm³))/20cm³
P(initial) = 337.5kPa ~ 338kPA
Which among the following mixtures will show tyndal effect?
i) copper sulphate solution
ii) sand in water.
iii) milk.
iv) starch solution
Answer:
milk and starch solution are the colloids, hence these will show the tyndall effect
Answer:
milk and starch solution
Explanation:
Tyndall effect is shown by colloidal solutions. It is not shown by true solutions or suspensions.
Milk and starch solution are colloidal solutions. They show tyndall effect. On the other hand, common salt and copper sulphate solution are true solutions. They do not show tyndall effect.
What is the pressure in atm exerted by 1.8 g of H2 gas exert in a 4.3 L balloon at 27ºC? R = 0.821(L*atm) / (mol*K)
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The pressure in atm exerted by 1.8 g of H₂ gas exert in a 4.3 L balloon at 27ºC is 5.12 atm
What is Ideal gas law ?The ideal gas law (PV = nRT) relates the macroscopic properties of ideal gases. An ideal gas is a gas in which the particles (a) do not attract or repel one another and (b) take up no space (have no volume).
Let's convert grams to moles (via molar mass).
Molar Mass (H₂) : 2 (1.008 g/mol)
Molar Mass (H₂) : 2.016 g/mol
1.8 grams H₂ 1 mole
---------------------- x ---------------------- = 0.893 moles H₂
2.016 grams
The Ideal Gas Law equation looks like this:
PV = nRT
In this equation,
P = pressure (atm) V = volume (L) n = moles R = Ideal Gas Constant (0.0821 L*atm/mol*K)T = temperature (K)After converting Celsius to Kelvin, you can put the given values into the equation and simplify to find the pressure.
P = ? atm R = 0.0821 L*atm/mol*K
V = 4.3 L T = 27 °C + 273.15 = 300.15 K
n = 0.893 moles
PV = nRT
P (4.3 L) = (0.893 moles) (0.0821 L*atm/mol*K)( 300.15 K)
P (4.3 L) = 22.0021
P = 5.12 atm
Therefore, The pressure in atm exerted by 1.8 g of H₂ gas exert in a 4.3 L balloon at 27ºC is 5.12 atm
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write any two conditions at which a body of certain mass weightless
Answer:
A body becomes weightless in a zero-gravity scenario and when a force is applied to a body that is equal and opposite to the force of gravity. If the body is falling only under the influence of gravity.
Answer:
A body becomes weightless in a zero-gravity scenario and when a force is applied to a body that is equal and opposite to the force of gravity.If the body is falling only under the influence of gravity.
the text of oxygen gas in the laboratory
Explanation:in testing for oxygen a glowing splint is used.
the glowing splint is brought in the presence of the test tube containing the gas
the glowing splint rekindles or lights up showing that oxygen is present.
this is a positive test because oxygen supports burning or combustion
Describe weighted average
Answer:
Explained below
Explanation:
In simple average, we just add all the given data variables and divide it by the number of data given.
However, when it comes to weighted average, what we do is that we multiply each given variable by their weights and then divide the sum of that by the sum of the weights.
Thus, if the variables are denoted by x and their weights are denoted by y, then we have;
Weighted average = Σ(xy)/Σy
mention two factors which affect pressure due to liquid contained in a vessel
Answer:
depth of the liquid and nature of liquid affects the pressure due to liquid contained in a vessel
Answer:
Two factors influence the pressure of fluids. They are the depth of the fluid and its density. A fluid exerts more pressure at greater depths
When it’s summer in the northern hemisphere what Season is it in the Southern Hemisphere
Answer:
Winter
Explanation:
I dont know but whatev
Answer:
Winter
Explanation:
The seasonal cycle in the polar and temperate zones of one hemisphere is opposite to that of the other. Therefore, When it is summer in the Northern Hemisphere, it is winter in the Southern, and vice versa.
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How many atoms of hydrogen are there in 36 g of NH4?
Answer:
hope it helps you
Explanation:
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I need help with question 5
Answer:
B a spring being stretched
