Al= [Ar] 3s^2 3p^1
for the third period the principal quantum number is n=3. the third
Pesticides and fertilizers are a major cause of
O air pollution
O acid rain
o the greenhouse effect
O groundwater pollution
Answer:
it means air pollution Environment. The chemicals and nutrients found in fertilizers, while beneficial for agricultural crops, can be lethal in high doses for fish, birds and other wildlife. Pesticides, designed to kill pests chemically, are also dangerous when leached into soil or groundwater supplies.
In ∆ABC, if sin A = and tan A = , then what is cos A?
Complete Question:
In ∆ABC, if sin A = 4/5 and tan A = 4/3, then what is cos A?
Answer:
[tex]cos A= \frac{3}{5}[/tex]
Explanation:
Given
[tex]sin A = 4/5[/tex]
[tex]tan A = 4/3[/tex]
Required
[tex]cos A[/tex]
In trigonometry;
[tex]tanA = \frac{sinA}{cosA}[/tex]
Multiply both sides by cosA
[tex]cos A * tanA = \frac{sinA}{cosA} * cos A[/tex]
[tex]cos A * tanA = sinA[/tex]
Divide both sides by tanA
[tex]\frac{cos A * tanA}{tanA} = \frac{sinA}{tanA}[/tex]
[tex]cos A= \frac{sinA}{tanA}[/tex]
Substitute values for sinA and tanA
[tex]cos A= \frac{4/5}{4/3}[/tex]
[tex]cos A= \frac{4}{5} / \frac{4}{3}[/tex]
[tex]cos A= \frac{4}{5} * \frac{3}{4}[/tex]
[tex]cos A= \frac{4 * 3}{5 * 4}[/tex]
[tex]cos A= \frac{3}{5}[/tex]
Answer in the correct significant figures: 31.2 x 4.13*
Answer:
1.29* 10^2
Explanation:
multiply them and then round
1. what is hard water.
2. Mention four sources of water.
3. write down the chemical formula of water.
4. What is purification of water.
5. Mention two importance of purification of water.
6. Mention 4 method used ot purify water. 7. Mention 4 impurities found in water.
8. Explain the term contaminated of water.
9. State two physical properties of water. 10. mention the names of of the elements that causes hardness in water.
Explanation:
Hard water is a type of water that can not easily lather with soap. Springs, wells, pipe-borneH20. The 2 is in basePurification of water is the cleansing of water to avoid diseases, germs, bacteria. To prevent diseases, to make the water safe for drinkingBoiling,chlorination, distillationSorry about number seven! This is when water is unsafe or dirty, it cannot be used for the purpose for which it is intended Water is tasteless, water is colourlessCalcium tetraoxosulphate(vi), Magnesium tetraoxo sulphate (vi) and Calcium hydrogen trioxocarbonateA chemical engineer is developing a process for producing a new chemical. One step in the process involves allowing a solution of potassium hydroxide to react with a solid. Which action would most likely increase the reaction rate for this step? using larger pieces of the solid using a more concentrated potassium hydroxide solution adding water to the system
Answer:
using a more concentrated potassium hydroxide
Explanation:
The option that would likely increase the rate of reaction would be to use a more concentrated potassium hydroxide.
The concentration of reactants is one of the factors that affect the rate of reaction. The more the concentration of the reactants, the faster the rate of reaction.
Granted that there are enough of the other reactants, increasing the concentration of one of the reactants will lead to an increased rate of reaction.
Hence, using a more concentrated potassium hydroxide which happens to be one of the reactants would likely increase the rate of reaction.
Answer:
using a more concentrated potassium hydroxide
Explanation:
How much energy has your body used, in joules, if your health
device indicates that 450 Calories were burned during your workout? How many
Calories are in a dinner containing 3.5 x 100 joules
Answer:
1,882.8 joules83.652 caloriesExplanation:
Given:
Amount in calories = 450 calories
Amount in joules = 3.5 × 100 joules
Find:
Change in joulesChange in caloriesComputation:
We know that,
1 calories = 4.184 joules
So,
Amount in calories = 450 calories
= 450 × 4.184
= 1,882.8 joules
Amount in joules = 3.5 × 100 joules
= [3.5 × 100] / 4.184
= 83.652 calories
Identify each of the highlighted materials as an element, a compound, or a mixture, and explain your reasoning.
Answer:
These are compounds.
Explanation:
As it is formed by chemically bonding of two elements C ( carbon) and H (hydrogen) .
Its not a mixture because mixture is Just dispersed of diferrent elements or a compound which are not in fix ratioAnswer:
Butane and benzene are both compounds. They contain multiple elements bonded together in a specific ratio. Kerosene and gasoline are mixtures because they are combinations of several compounds. Oxygen is an element because it is made up of only one type of atom.
Explanation:
explain why crude oil is a fossil fuel
how to unscramble dtneinreigs
Answer:
Ingredients OR tenderising
Explanation:
WILL MARK BRAINLY IF GOOD ANSWER :)
Chlorine and oxygen are both gases at room temperature. What are some characteristic properties of chlorine that distinguish it from oxygen?
Answer:
Well one characteristic is electical energy transforms into thermal energy and gases and the state of matter(one of the distinct form i which matter exist)
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.
You need 100.00 mL of H20 and 5.00 mL of
liquid plant food to make a solution for your
plants. You forgot to bring a measuring cup
out to the greenhouse, but you do have a scale
and know that the density of H2O is 1.00
g/cm", the density of liquid plant food is 1.21
g/cm' and 1 cm° = 1 mL. How much of the
liquid plant food would you use?
Answer:
6.05 g
Explanation:
Use the density to convert the volume to a weight.
(5.00 mL) × (1.21 g/mL) = 6.05 g liquid plant food
You will need 6.05 g liquid plant food.
¿Como pasar 254 meses a minutos?
Por favor ayudaaa!!
Le doy corona a la respuesta
Answer:
Ver las respuestas abajo.
Explanation:
Este problema se puede resolver conociendo la relacion entre horas y minutos, sabemos que:
1 hora [h] → 60 minutos [min]
De esta manera:
2 [min] = 2/60 = 0.033 [h]
15 [min] = 15/60 = 0.25 [h]
30 [min] = 30/60 = 0.5 [h]
10 [min] = 10/60 = 0.166 [h]
6 [min] = 6/60 = 0.1 [h]
20 [min] = 20/60 = 0.33 [h]
5 [min] = 5/60 = 0.0833 [h]
A 50.51 g sample of a compound made from phosphorus and chlorine is decomposed. Analysis of
the products showed that 11.39 g of phosphorus atoms were produced. What is the empirical formula
of the compound?
Answer:
pcl3 is the empirical formula of the compound
find the empirical formula of the compound containing 11.3% of carbon, 43.4 % of sodium 45.3 % of oxygen
Answer:
CNa203
Explanation:
thats is method in the picture send
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.
Explanation:
Answer:
A measurable property that can be observed typically and explains any matter or organism's appearance and physical behavior is called a physical property. Examples of physical properties are appearance, boiling point, freezing point, melting point, colors, odor, mass, density, solubility. Properties that are only observed during a reaction or change in the composition of a matter is called a chemical property. These properties describe the internal part of anything and explain how it behaves when reacted with other chemical substances. Examples are enthalpy, entropy, reactivity, flammability, oxidation state, acidity, basicity. Some physical properties are reversible or sometimes irreversible. Like the change of states of matter is reversible, and the growth of an organism is irreversible. The same thing with the chemical properties. There are reversible chemical reactions(formation of ammonium chloride) and irreversible chemical reactions. (burning of a chemical substance). After knowing all about these properties, the most fundamental difference is that the physical properties can be measured without any chemical change in them. But a chemical property is measurable when the substance goes through a chemical reaction.
Explanation:
Which scientist developed a new model of planetary motion?
Answer: Johannes Kepler
Answer:
i believe the answer us kepler
Explanation:
Propane (C3H8), a common fuel, reacts with oxygen to form carbon dioxide and water according to the equation below: C3H8 + 5O2 → 3CO2 + 4H2O If a propane heater burns 38.95 g C3H8, it consumes
Answer:
0.8833 mole of C3H8
Explanation:
Given:
Mass of C₃H₈ (Propane) = 38.95 gram
Computation:
Molar mass of C = 12.01
Molar mass of H = 1.008
Molar mass of C₃H₈ (Propane) = 3(12.01) + 8(1.008)
Molar mass of C₃H₈ (Propane) = 36.03 + 8.064
Molar mass of C₃H₈ (Propane) = 44.094
Number of mol in 38.95 gram Propane = Mass / Molar mass
Number of mol in 38.95 gram Propane = 38.95 / 44.094
Number of mol in 38.95 gram Propane = 0.88334
Answer:
Use the Periodic Table to find molar masses.
Propane (C3H8), a common fuel, reacts with oxygen to form carbon dioxide and water according to the equation below:
C3H8 + 5O2 → 3CO2 + 4H2O
If a propane heater burns 38.95 g C3H8, it consumes
38.95 mol C3H8.
0.8830 mol C3H8.
1 mol C3H8.
44.10 mol C3H8.
Part 2
How many moles of oxygen are required to produce 37.15 g CO2?
37.15 g CO2 = 1.407 mol O2
Part 3
What mass of propane is necessary to react with the amount of oxygen calculated in the previous question?
12.41 g C3H8
How do experiments help scientists learn about the world?
A. Experiments explain scientific theories.
B. Experiments prove the scientists' hypotheses.
C. Experiments test the scientists' ideas.
D. Experiments correct old ideas.
Answer:
C. Experiments test the scientists' ideas.
Explanation:
Experiments test the scientists' ideas. Therefore, the correct option is C.
By testing ideas and hypotheses, experiments are an essential part of the scientific method and aid scientists' understanding of the world. Science uses regulated procedures to detect particular phenomena, track results, and collect data. These studies give researchers a chance to investigate cause-and-effect relationships, detect patterns, and draw conclusions based on the data. Scientists can test their ideas, theories, and predictions by systematically adjusting various factors to see whether experimental results confirm or disprove them.
Therefore, the correct option is C.
Learn more about Experiments, here:
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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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3.87 moles of iron bromide yielded10.4 moles of sodium bromide
Answer: 89.57 %
Hope it helps
PLEASE HELP URGENT!!
What is the SI system? What are its benefits?
Answer:
The SI system : The international system of units.
It is a scientific method of expressing the magnitudes or quantities of important natural phenomena.
Benefits of SI system
It is a coherent system of units ( a system based on certain sets of fundamental units )It is a rational system of units ( it assigns only one unit to a particular physical quantity )Which of the following statements is true? A. Isotopes of the same element have the same number of protons and neutrons. B. Isotopes have the same physical properties as the normal atom but different chemical properties. C. Isotopes have the same chemical properties as the normal atom but different physical properties. D. If an isotope of one element has the same atomic mass as another element, they will have the same properties.
Answer:
B
Explanation:
Isotopes have the same number of protons but different number of neutrons.
The true statement is,
Isotopes have the same chemical properties as the normal atom but different physical properties.So, option C is correct one.
What is isotopes?The elements have same number of proton but different number of neutrons.Example: hydrogen, deuterium, tritiumWhy isotopes of same elements have different physical properties?The isotopes have different physical properties like freezing point , mass, melting or boiling point etc because they have different mass number .
learn about isotopes,
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How many gram of zinc will have to be treated with dilute hydrochloric acid to liberate 1.85 dm³ of hydrogen at 27°C and 750mmHg?
Answer:
Explanation:
given
volume=1.85 d m^3
T=27 degree C=27+273 k=300 k
P=750 mmHg
mass of zinc=?
we know that PV=nRT
n=m/M
PV=mRT/M
M for zinc=65.4
PVM=mRT
m=PVM/RT
m=750*1.85*65.4/0.0821*300
m=90742.5/24.63
m=3684
hope this will help u
which of the following molecules would you expect to be optically active
1. CCl2F2
2. 2-methyl butane
3. butan-2-ol
Answer:
waaaaaaaaaaqwwwwwwwwwwww
number of moles from the formula is multiplied by the atomic mass of each _______, and then all those masses are added together.
A)
atom
B)
particle
C)
molecule
D)
electron
Answer:
D. electron
Explanation:
using chemical equations, show the different stages of fermentation
please I need help urgently!!!
Answer:
in the fermentati0n process glucose [C6H12O6]c of food is converted into ethanol [ethyl alchol, C2H5OH] and Co2 by yeast cell .In this process yeast cell produce in vertase and zymase enzyme which convert glucose into alcohol .
i.e. c6H12O6========> C2H5OH+Co2+energy
Calcium oxide reacts with water in a combination reaction to produce calcium hydroxide: CaO (s) + H2O (l) → Ca(OH)2 (s) In a particular experiment, a 2.00-g sample of CaO is reacted with excess water and 2.14 g of Ca(OH)2 is recovered. What is the percent yield in this experiment? a. 107 b. 1.07 c. 2.88 d. 81.1 e. 93.3
Answer:
The option closest to the percentage yield is option;
d. 81.1
Explanation:
The given chemical equation of the reaction is presented as follows;
CaO (s) + H₂O (l) → Ca(OH)₂
The mass of CaO in the experiment, m = 2.00 g
The volume of water with which the CaO was reacted = Excess volume of water
Number of moles = Mass/(Molar mass)
The mass of Ca(OH)₂ recovered, actual yield = 2.14 g
The molar mass of CaO = 56.0774 g/mol
The number of moles of CaO in the reaction, n₁ = 2.00 g/(56.0774 g/mol ≈ 0.036 moles
The molar mass of Ca(OH)₂ = 74.093 g/mol
The number of moles of Ca(OH)₂ in the reaction, n₂ = 2.14 g/(74.093 g/mol) ≈ 0.029 moles
From the given chemical reaction, one mole of CaO reacts with one mole of H₂O to produce one mole of Ca(OH)₂
Therefore, 0.036 moles of CaO will produce 0.036 moles of Ca(OH)₂
Mass = Number of moles × Molar mass
The mass of 0.036 moles of Ca(OH)₂ ≈ 0.036 moles × 74.093 g/mol = 2.667348 grams
∴ The theoretical yield of Ca(OH)₂ = 2.667348 grams
[tex]Percentage \ yield = \dfrac{Actual \ yield}{Theoretical \ yield} \times 100 \%[/tex]
The percentage yield = (2.14 g)/(2.667348 grams) × 100 = 80.23%
Therefore, the option which is closest is option d. 81.1.
A 46.9 gram sample of a substance has a volume of about 3.5 centimeters3. It is solid at a room temperature of 23ºC. Out of the four substances whose properties are given, which is the most likely identity of this substance?
THIS IS THE COMPLETE QUESTION BELOW
46.9 gram sample of a substance has a volume of about 3.5 centimeters3. It is solid at a room temperature of 23ºC. Out of the four substances whose properties are given, which is the most likely identity of this substance?
Substance Density (g/cm3) Melting Point (°C) Boiling Point (°C)
molybdenum 10.28 2,623 4,639
mercury 13.53 -39 357
hafnium 13.31 2,233 4,603
lead 11.34 327 1,749
A.
molybdenum
B.
mercury
C.
hafnium
D.
lead
Answer :
The correct option is OPTION C.
(C) Hafnium
Explanation;:
We were given the mass of substance as (m) = 46.9 g
The Volume of substance as (V) = 3.5 Cm^3
But we know Density of substance.= Mass/it's Volume
Then Density=46.9/3.5
=13.4g/Cm^3
From the questionthe given substance is solid at room temperature, and let us take Mercury as an example , Mercury is liquid at room temperature. ThenMercury cannot be the answer.
Base on the determined density which is 13.4 and the density of Hafnium also is 13.31 g/cm3 and it is solid at room temperature. Therefore, Hafnium is the only likely element here.
Determine the empirical formula for compounds that have the following analyses. a. 28.4% copper, 71.6% bromine b. 39.0% potassium, 12.0% carbon, 1.01% hydrogen, and 47.9% oxygen c. 77.3% silver, 7.4% phosphorus, 15.3% oxygen d. 0.57% hydrogen, 72.1% iodine, 27.3% oxygen
Answer:
See explanation
Explanation:
Cu- 28.4/63.5, Br- 71.6/80
Cu- 0.447/0.447, Br- 0.895/0.447
Cu- 1, Br - 2
Empirical formula = CuBr2
b)
K- 39.0/39, C-12.0/12, H- 1.01/1, O- 47.9/16
K= 1, C-1, H- 1. O-3
Empirical formula= KHCO3
c)
Ag- 77.3/108, P-7.4/31, O-15.3/16
Ag-0.716/0.239, P- 0.239/0.239, O-0.956/0.239
Ag-3, P-1, O-4
Empirical formula= Ag3PO4
d)
H-0.57/1, I- 72.1/127, O-27.3/16
H- 0.57/0.57, I- 0.57/0.57, O-1.71/0.57
H-1, I-1, O- 3
Empirical formula= HIO3