Explanation:
Boron is a non metallic element and the only non-metal of the group 13 of the periodic table the elements. Boron is electron-deficient, possessing a vacant p-orbital. ... It reacts with metals to form borides. At standard temperatures boron is a poor electrical conductor but is a good conductor at high temperatures
Which properties are examples of chemical properties? Check all that apply.
reactivity
color
hardness
boiling point
combustibility
shape
Answer:
1.Reactivity
2.combustibility
3.Shape
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Explanation:
a weather balloon is inflated to a volume 2.2 10square3 L with 374g of helium. what is the density of helium in grams per liter
Answer:
Density = 0.17 g/L
Explanation:
It is given that,
Volume of the inflated balloon filled with Helium, [tex]V=2.2\times 10^3\ L[/tex]
Mass, m = 374 g
We need to find the density of helium. It is equal to its mass per unit volume. It can be given by :
d =m/V
[tex]d=\dfrac{374\ g}{2.2\times 10^3\ L}\\\\=0.17\ g/L[/tex]
So, the density of helium in the balloon is 0.17 g/L.
A solution of a concentration of H+ (10-4 M) has a pH of
Answer:
pH = 4
Explanation:
Step 1: Given data
Concentration of H⁺ ions in the solution ([H⁺]): 10⁻⁴ M
Step 2: Calculate the pH of the solution
We will use the definition of pH.
pH = -log [H⁺]
pH = -log 10⁻⁴ M
pH = 4
The pH of the solution is 4. Considering the pH scale, given the pH is lower than 7, the solution is acidic.
In N, +0,
N,O,, nitrogen is reduced
A True
B. False
Answer:
A.True
Explanation:
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A chemical reaction is shown below:
Glucose + Oxygen --> Water + Carbon Dioxide
How many grams of water would be produced if the reaction contained each of the following:
20 g of glucose
15 g of oxygen
30 g of carbon dioxide
SELECT AN ANSWER
15 g of water
35 g of water
65 g of water
5 g of water
Answer:
Mass = 8.46 g
Explanation:
Given data:
Mass of water produced = ?
Mass of glucose = 20 g
Mass of oxygen = 15 g
Solution:
Chemical equation:
C₆H₁₂O₆ + 6O₂ → 6H₂O + 6CO₂
Number of moles of glucose:
Number of moles = mass/molar mass
Number of moles = 20 g/ 180.16 g/mol
Number of moles = 0.11 mol
Number of moles of oxygen:
Number of moles = mass/molar mass
Number of moles = 15 g/ 32 g/mol
Number of moles = 0.47 mol
now we will compare the moles of water with oxygen and glucose.
C₆H₁₂O₆ : H₂O
1 : 6
0.11 : 6/1×0.11 = 0.66
O₂ : H₂O
6 : 6
0.47 : 0.47
Less number of moles of water are produced by oxygen thus it will limit the yield of water and act as limiting reactant.
Mass of water produced:
Mass = number of moles × molar mass
Mass = 0.47 mol ×18 g/mol
Mass = 8.46 g
Which trait can a plant acquire during its lifetime?
O A. A damaged stem
OB. A blue flower color
O C. A long, narrow leaf shape
O D. A smooth seed texture
Answer:
OB
Explanation:
wat does aquire mean
Answer:
a
Explanation:
a damaged stem
Need help on 8,9, and 10. ONLY if you know them please.
Answer:
D, D, A
Explanation:
(a) Some sodium chloride was found to be contaminated with Copper (ii) oxide. Describe
how a sample of sodium chloride can be separated from the mixture.
Answer:
A mixture of sodium chloride and sand in water can be separated by the process of filtration and then by the process of distillation.
Answer:
Explanation:
As this oxide is insoluble in water you would dissolved the sample of sodium chloride in water and filter off the oxide.
Then concentrate the liquid by boiling and cooling, to get crystals of pure sodium chloride.
which object is a good conductor of heat and electricity?
A. rubber tires
B. rubber boots
C. metal gate
D. wooden sign
Answer:
C
Explanation:
Metals are good conductors of heat
The total number of oxygen atoms in Al2(SO4)3 is
Al2(SO4)3 =
Al2 S3 O12
Total atom :
Al = 2
S = 3
O = 12
How many moles of atoms are in 8.1 × 10^5
g
Pb?
Answer in units of mol.
Answer:
3900 mol Pb
General Formulas and Concepts:
Chemistry - Atomic Structure
Reading a Periodic TableUsing Dimensional AnalysisExplanation:
Step 1: Define
8.1 × 10⁵ g Pb
Step 2: Identify Conversions
Molar Mass of Pb - 207.2 g/mol
Step 3: Convert
[tex]8.1 \cdot 10^5 \ g \ Pb(\frac{1 \ mol \ Pb}{207.2 \ g \ Pb} )[/tex] = 3909.27 mol Pb
Step 4: Check
We are given 2 sig figs. Follow sig fig rules and round.
3909.27 mol Pb ≈ 3900 mol Pb
The diagram below shows the main parts of the respiratory system.
Nose
ch
3
Lungs
Diaphragm
Which of these correctly names the parts of the respiratory system numbered 1
through 5 in the diagram above?
A 1. larynx, 2. pharynx, 3. trachea, 4. bronchi, 5. alveoli
B 1. pharynx, 2. larynx, 3. trachea, 4. bronchi, 5. alveoli
C 1. pharynx, 2. larynx, 3. bronchi, 4. trachea, 5. alveoli
Answer:
pharynx > larynx>trachea> bronchi>alveoli (so B)
Explanation:
nasal cavities (or oral cavity) > pharynx > trachea > primary bronchi (right & left) > secondary bronchi > tertiary bronchi > bronchioles > alveoli (site of gas exchange)
3. Two people are playing tug of war. One person pulls to the right with 32 N of force. The other person pulls to the left with 37 N of force. How strong is the net force and in which direction?
The net force = -5 N
The direction : to the left(negative sign)
Further explanationNet force : the sum of all forces acting on an object
Force is a vector quantity that has both magnitude and direction,
We agree that the move up and to the right is a positive sign, while down and to the left is a negative sign.
The direction of the force (horizontal motion) is to the right (+32 N), and to the left (-37 N), so the net force :
[tex]\tt \sum F=F~right-F~left\\\\\sum F=32-37\\\\\sum F=-5~N[/tex]
Which of the following makes sense to round to the nearest 10?
A. Your friend's telephone number
B. The PIN code of your city or town
C. The number of pages in your Maths book
D.t he year of your birth
Answer:
C
Explanation:
You can’t round a phone number or Pin code
why would you round your birth year?
Please give answers from h
Answer:
option b
Explanation:
A4 g sugar cube (Sucrose : C 12 H 22 O 11 ) is dissolved in a 350 ml teacup of 80 C water. What is the percent composition by mass of the sugar solution ? Density of water at 80 degrees * C = 0.975g / m * l Select one :- 1.96\% . 1.63% 1.36 % d% e 1.16 \%
Answer:
%Sgr = 1% (1 sig.fig.)
Explanation:
mass water = 350ml x 0.975g/ml = 341.25g
mass sugar added = 4g
solution mass = 341.25g + 4g = 345.25g
%sugar = (4g/345.25g)·100% = 1.1586% ≅ 1% (1 sig.fig)
The percent composition by the mass of the sugar solution is:
e. 1.16 %
This can be calculated by using mass of sugar.
Calculation of percent composition:Mass of water = 350ml x 0.975g/ml = 341.25g
Mass of sugar added = 4g
Total solution's mass = 341.25g + 4g = 345.25g
%sugar = (4g/345.25g)·100%
%sugar= 1.1586% ≅ 1.16 %
Thus, the percent composition of sugar is 1.16%. Hence, option E is correct.
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Complete Table G to view the effect of surface area on the rate of reaction by transferring your data from Tables D and E to Table G.
Which form of the sodium bicarbonate tablet dissolves the fastest?
Answer:
The crushed tablet dissolves fastest among the three forms.
Explanation:
The experiment is aimed at determining the effect of surface area of reactants on reaction rate.
Sodium bicarbonate tablets are provided and divided into three groups of consisting of three trials each. The temperature of the water is kept constant at 20°C. The first group consists of three tablets of sodium bicarbonate dissolved in individual trials in water. The second group consists of three quarter tablets of sodium bicarbonate dissolved in individual trials in water. The third group consists of three crushed tablets of sodium bicarbonate dissolved in individual trials in water.
The results shows that the average time for the dissolution of the first group is 51 seconds; the second group is 42 seconds while the third group is 17 seconds.
Therefore, it can be concluded that increasing the surface area of reactants increases the rate of reaction. This is because more reactant molecules are exposed for dissolution by water with increase in surface area.
Answer:
cold water
Explanation:
Which of the following represents a compound made of five molecules co5 c2o5 c50 5co2
Answer:
The answer is: 5co2
component of fuel for engines is organic compound or hydrocarbons
CnHm is the general closed chemical formula of liquid hydrocarbons used as a fuel in the internal combustion engines. However, hydrocarbons consist of hydrogen and carbon and also small amounts of O2, H2, S, H2O, and some metals containing crude oil derivatives .
g 3.232 g of an unknown solid is dissolved in 363.2 g of benzene. The freezing point of the solution decreases by What is the molar mass of the unknown solid. The freezing point depression constant for benzene is
Answer:
18.2g/mol is the molar mass of the unknown solid assuming change in freezing point is 2.5°C
Explanation:
In this problem, there is no value of the freezing point depression and the constant for benzene, if:
Freezing point decreases by 2.5°C
And freezing point depression constant for benzene is 5.12°C/m
We can solve the problem as follows:
The freezing point depression is a colligative property that follows the equation:
ΔT = kf*m*ï
Where ΔT is change in temperature (We are assuming is 2.5°C)
Kf is freezing point depression constant for benzene (5.12°C/m)
m is molality of solution (Moles solute / kg solvent)
i is Van't hoff factor (For all solutes dissolved in organic solvents = 1)
Solving for m:
2.5°C = 5.12°C/m*m*1
m = 0.4883m
As molality is defined as moles of solute / kg of solvent and kg of solvent are 0.3632kg:
0.4883m = moles solute / 0.3632kg
0.177 moles of solute
Molar mass is defined as the mass of one mole of substance. Thus, molar mass of an unknown solid is:
3.232g / 0.177 moles of solute =
18.2g/mol is the molar mass of the unknown solid assuming change in freezing point is 2.5°C
What is the formula for Na+ F-
what is a molecule? PLEASE DONT LOOK THIS UP I WILL GET IN TROUBLE!
Answer:
A molecule is a group of two or more atoms that form the smallest recognizable unit into which the structure and chemical properties of that substance can be divided and preserved by a pure substance.
Explanation:
Arrange the following 0.10 M aqueous solutions in order of increasing pH:
a. NaOH
b. HBr
c. NaCH3CO2
d. KBr
e. NH4Br.
Answer:
The correct answer is HBr<NH4Br<KBr<NaCH3CO2<NaOH.
Explanation:
When salt is added to the water, the formation of acid and base takes place. The pH helps in predicting the basicity, acidity, and neutrality of a compound.
It is known that NaOH is a strong base, thus, its solution will be basic, and therefore, the pH of NaOH will be greater than 7.
The solution of HBr will be acidic as HBr is the strong acid, thus, its pH will be less than 7.
In dissolving NaCH3CO2 in water, the formation of CH3COOH, which is a weak acid, and NaOH that is, a strong base takes place. Therefore, as NaOH is the strong base, the solution will be basic, and the pH of NaCH3CO2 will be greater than 7.
On dissolving KBr in water, HBr, that is, a strong acid, and KOH, that is, a strong base is produced. Therefore, as HBr is the strong acid, and KOH is the strong base, the solution will be neutral. Thus, the pH of KBr will be equivalent to 7.
On dissolving NH4Br in water, the formation of HBr, that is, strong acid, and NH4OH, that is, the weak base takes place. Therefore, as HBr is the strong acid, the solution will be acidic, and the pH of NH4Br will be less than 7.
Hence, the increasing order of pH of 0.10 M aqueous solution will be,
HBr<NH4Br<KBr<NaCH3CO2<NaOH
The order of increasing pH of the solutions is; HBr < NH4Br < KBr < NaCH3CO2 < NaOH.
pH is a number that indicates the degree of acidity or alkalinity of a substance. The pH scale ranks from 0 - 14. 0 - 6.9 indicates acidity, 7 indicates neutrality while 8 - 14 indicates alkalinity.
The order of increasing pH of the solutions is; HBr < NH4Br < KBr < NaCH3CO2 < NaOH. Recall that NH4Br yields an acidic solution while NaCH3CO2 yields a basic solution.
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Because any natural element used in the cathode produced negative particles that bent to a positive charge, scientists concluded that:
A) all atoms contained negative electrons
B) all atoms are actually negative
C) atoms were indivisible and had no sub-particles
D) metals contained positrons
Because any natural element used in the cathode produced negative particles that bent to a positive charge, scientists concluded that ll atoms contained negative electrons.
What is cathode ?A polarized electrical device's cathode is the electrode from which a regular current exits. The abbreviation CCD, which stands for Cathode Current Departs, might be used to remember this definition. Positive charges move in the direction described by a conventional current.
A cathode is a drawback. As an electron donor, it functions. It serves as an acceptor of electrons. The anode of an electrolytic cell is where the oxidation reaction occurs.
The negatively charged ions are drawn to the cathode, which is the negative electrode. Lead ions travel through the metal use negatively charged terminal of the battery and onto the lead ions because metal ions are usually positive. There must be a way to remember cathodes and anodes, cations and anions.
Thus, option A is correct.
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(b) An unknown volume of 3.50 M potassium phosphate, K,PO, solution is added to 0.210 L of water
to form a 0.700 M K3PO, solution. Calculate the molarity of potassium ions, K in the solution.
Answer:
[tex]M_{K^+}=2.1M[/tex]
Explanation:
Hello!
In this case, since we know the initial and final concentrations and the added volume of water, we can write:
[tex]3.50M*V_1=0.700M(0.210L+V_1)[/tex]
Which can be solved for the initial volume as follows:
[tex]3.50M*V_1-0.700M(0.210L+V_1)=0\\\\3.50V_1-0.147-0.7V_1=0\\\\2.8V_1=0.147\\\\V_1=\frac{0.147}{2.8}=0.0525L[/tex]
It means that the final volume is:
[tex]V_2=0.210L+0.0525L=0.2625L[/tex]
Next, we compute the moles of potassium phosphate in solution:
[tex]n_{K_3PO_4}=0.2625L*0.700\frac{molK_3PO_4}{L}=0.184molK_3PO_4[/tex]
Then, since 1 mol of potassium phosphate has 3 moles of potassium (K's subscript), we compute the moles of potassium ions:
[tex]n_{K^+}=0.184molK_3PO_4*\frac{3molK^+}{1molK_3PO_4}=0.551molK^+[/tex]
Finally, the concentration of potassium ions turns out:
[tex]M_{K^+}=\frac{0.551molK^+ }{0.2625L}\\\\ M_{K^+}=2.1M[/tex]
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Plz help me
What is a challenge in wild animal photography?
A. They are easy to close to
B. They don’t move much
C. You can’t position them
D. All of the above
Answer:
c
Explanation:
Because they are in the wild and they move a lot because they freedom. They are easy to close but you can not position so it is c. Pls tell if I am wrong.
How much heat is required to raise the temperature of a 175 g piece of aluminum from 37.0 oC to 92.0 oC?
Answer:
2.07 × 10³ cal
Explanation:
Step 1: Given and required data
Initial temperature: 37.0 °CFinal temperature: 92.0 °CMass of aluminum: 175 gSpecific heat capacity of aluminum (c): 0.215 cal/g.°CStep 2: Calculate the change in the temperature experienced by the aluminum piece
ΔT = 92.0 °C - 37.0 °C = 55.0 °C
Step 3: Calculate the heat required (Q)
We will use the following expression.
Q = c × m × ΔT
Q = 0.215 cal/g.°C × 175 g × 55.0 °C
Q = 2.07 × 10³ cal
Define heating effect?
Explanation:
when the current passes through a conductor the electrons have to face the resistance of the conductor which results in the loss of energy and this loss of energy gets converted into heat energy and it is called heating effect.good night.hope it will help uh.
Atomic number of a member of halogens
When 2.00 g of silver nitrate and 2.50 g of sodium sulfide in different solutions combine to react, 1.25 g of precipitate are collected. * The text box will not allow you to use subscript. If you want to type the chemical formula for iron(III) sulfate, Fe2(SO4)3, it will need to be typed as Fe2(SO4)3. Remember that the symbol for iron, Fe, is not "fe" or "FE." Do not include the state of matter for each formula. • What is the chemical formula* for the product? Remember that spectator ions do not form a product in solutions. • What is the theoretical yield, in gram(s) for the solid product? • What is the chemical formula for the limiting reagent? • What is the chemical formula for the excess reagent? • What is the percent yield for the reaction? • How many gram(s) of the excess reagent is/are left over?
Answer:
See Explanation ...
Explanation:
2AgNO₃(aq) + Na₂S(aq) => 2NaNO₃(aq) + Ag₂S(s)
given 2.0g 2.5g Spec Ions Driving Force ppt
= 2.0g/169.8g·mol⁻¹ =2.5g/78g·mol⁻¹
= 0.012mol =0.032mol
0.012/2=>0.006* 0.032/1=>0.032*
Limiting Reactant => *Dividing moles by respective coefficient => Limiting Reactant is the smaller resulting value. Therefore AgNO₃ is the Limiting Reagent
Theoretical Yield of ppt Ag₂S(s) = 1/2(0.012 mol) = 0.006 mol Ag₂S(s) = 0.006mol(246g·mol⁻¹ ) = 1.48g Ag₂S(s)
%Yield = (Lab Yield/Theoretical Yield) x 100% = (1.25g/1.48g)100% = 84%
Reagent in Excess => Na₂S(aq) => 0.032mol is given but only 0.016mol is consumed in the reaction. That is, (0.032 - 0.016)mol = 0.016mol Na₂S(aq) remains in excess = (0.016mol)(78g·mol⁻¹) = 1.25g Na₂S(aq) in excess.