Its A. Explanation:I just know
What percentage of the Periodic Table of Elements is Metals?
80 percent
About 80 percent of the elements are metals (shiny elements that conduct heat and electricity well), and 15 percent of the elements are nonmetals (poor conductors of heat and electricity). The remaining elements are metalloids, which share properties of both metals and nonmetals.
Answer:
80% of the Periodic Table consists of metals and 15% non-metals and 5% other elements.
Explanation:
As atoms get smaller,valance electrons are getting closer or farther away?
Answer:
valence electrons get closer but rest of them are remain same
How might a firefighter use chemistry?
A. Chemistry can help a firefighter plan an escape route through a
burning building
B. Chemistry can help a firefighter understand combustion and how
to put out fires.
C. Chemistry can help a firefighter understand how much of a load
the floors of a burning building can hold,
D. Chemistry can help a firefighter plan an exercise routine to prepare
for fires
Answer:
me has answer
Explanation:
b
Speed is the rate of change of position expressed as _____ traveled per unit of time.
Answer:
distance traveled per unit of time.
A group of students were asked to design a device that converts light energy into heat. They built a small solar oven using a tin can and aluminum foil. The device reflects light into the can, warming up its contents.
Which action would most improve the design of the solar oven?
O A. Add a mirror to reflect light away from the can.
O B. Use hand lenses to focus the light into the can.
O c. Add a fan to make sure the food is evenly warmed.
O D. Change the tin can to a box with a lid to Increase cooking space.
Answer:
answer is b
Explanation:
I think it is b. I don't know what land lenses are but focusing light on the can would heat it up more.
significance of symbol Mg
Answer:
Magnesium Magnesium is used in products that benefit from being lightweight, such as car seats, luggage, laptops, cameras and power tools. It is also added to molten iron and steel to remove sulfur. As magnesium ignites easily in air and burns with a bright light, it's used in flares, fireworks and sparklers.I hope this helps you !!What happens to the molecules of a gas when the gas is heated?
A.
The gas becomes a liquid.
B.
The molecules collide less frequently.
C.
No change occurs with regard to the molecules.
D.
The average speed of the molecules increases.
Answer:
the correct answer is D because the heat causes the molecules to speed up
for the reaction 2nh3(g)↽−−⇀ 3h2(g)+n2(g), if 15.8 grams of ammonia produced 1.87g of hydrogen, what was the percent yield
Answer:
75%
Explanation:
So, the reaction will consume 1 mole of hydrogen gas and produce
1mole H2⋅2 moles NH33moles H2=0.667 moles NH3
at 100% yield. This represents the reaction's theoretical yield.
Now, you know that the reaction produced 0.50 moles of ammonia. This represents the reaction's actual yield.
In order to find the percent yield, you need to figure out how many moles of ammonia are actually produced for every 100 moles of ammonia that could theoretically be produced.
You know that 0.667 moles will produce 0.50 moles, so you can say that
100moles NH3.in theory⋅0.50 moles NH3.actual0.667moles NH3.in theory=75 moles NH3.actual
Therefore, you can say that the reaction has a percent yield equal to
% yield = 75%
(01.07 HC)
A student collected the data shown in the table below during an experiment.
Liquid Characteristics
Liquid Characteristics
Boiling Point Freezing Point Color Expansion per Degree Change in Temperature
Mercury 357 °C −39 °C shiny silver gray relatively lower
Alcohol 78 °C −115 °C colorless relatively higher
Based on the data, which of the following conclusions can be made about the use of mercury and alcohol thermometers?
A mercury thermometer can measure the freezing point of a liquid that freezes at −80 °C.
An alcohol thermometer can measure the boiling point of a liquid that boils at 80 °C.
A mercury thermometer is better to measure very small changes in temperature.
An alcohol thermometer is better to measure the boiling points of colorless liquids.
Answer: a mercury thermometer is better to measure very small changes in temperature
Explanation:
i took the test and got it right
Answer:
the answer is C, a mercury thermometer is better to measure very small changes in temperature.
Explanation:
i just took the test and it was correct :)
Look at the diagram. Which shows the correct arrangement of electrons in a hydrogen chloride molecule?
Answer:
D............................
There are two types of chemical compound one is covalent compound and another is ionic compound, covalent compound formed by sharing of electron and ionic compound formed by complete transfer of electron. The correct representation is option D.
What is chemical Compound?Chemical Compound is a combination of molecule, Molecule forms by combination of element and element forms by combination of atoms in fixed proportion.
Covalent bond is present in molecule HCl. Hydrogen has 1 electron in its outermost shell. Chlorine has 7 electrons in its valence shell. So one one electron from each element is shared between them to form a covalent bond.
Therefore, the correct representation of arrangement of electrons in a hydrogen chloride molecule is option D.
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rank the crystal lattice structures in order of decreasing efficiency of space in the structure.
Rank the crystal lattice structures in order of decreasing efficiency of space in the structure.
1. Simple cubic
2. Body centered cubic
3. Face centered cubic
4. Hexegonal close packed
Mercury is an environmental pollutant that is produced by the burning of
fossil fuels and can be toxic to wildlife and humans. What does this show
about the impact of chemicals on the environment?
A. The harm chemicals could have on the environment outweighs the
benefits that people get from the chemicals.
B. People cannot control the negative effects of chemicals on the
environment.
C. All chemicals that people introduce into the environment are
harmful.
D. The beneficial effects people get from chemicals may have
unintended harmful effects on the environment,
Vinegar is an acid. Based on
what you know about the
properties of acids and bases,
which would you expect from
vinegar?
A. It should feel slippery.
B. It will release OH-in water.
C. It will release H+ in water.
Answer:
C
Explanation:
Acids contain H plus ions. When within a solution or neutralised these ions are released.
The substance which gives H+ ion are called as acid. Vinegar is an acid because it will release H+ in water. Therefore, option C is correct.
What is vinegar ?Acetic acid and water are combined to create vinegar through a two-step fermentation process. First, yeast consume any liquid derived from a plant source, such as fruits, whole grains, potatoes, or rice, and feed on the sugar or starch therein. It ferments into alcohol.
White vinegar typically contains 93–96% water and 4-7% acetic acid. It can be used to cook, bake, clean, and control weeds. It may also help with weight loss and decrease cholesterol and blood sugar levels.
The sugar is converted to ethanol (ethyl alcohol) by yeast and bacteria in a two-step fermentation process, which is followed by the production of acetic acid. Vinegar is acidic because it contains acetic acid.
Thus, option C is correct.
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Identify the total number of molecules in the chemical formula: 6CH4 a 6 b 10 c 24 d 30
Answer: A.6
Explanation:
The total number of molecules in the chemical formula is 6
What is a molecule?
Molecules are the smallest particle of a substance that has all of the physical and chemical properties of that substance. Molecules are made up of one or more atoms.
The correct form of question will be:-6 molecule of methane CH₄
6CH4
a) 6 c) 10 c) 24 d) 30⇒ Number of aton of carbon is 6
⇒Number of atom of hydrogen is 24
⇒Total number of atom is 30
What is an atom ?
An atom is a particle of matter that neither be created nor be destroyed. An atom consists of a central nucleus that is usually surrounded by one or more electrons. Each electron is negatively charged. The nucleus is positively charged, and contains one or more relatively heavy particles known as protons and neutrons.
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What pressure in atmospheres is equal to 45.6 K PA
Answer:
0.450037
Explanation:
Divide kPa by 101.325 as that is 1 atmospheric.
Hope that helps
Answer:
One atmosphere is equal to 101.33 kilopascal
So to change 45.6 kPa to atm, you would divide it by 101.33 kPa
[tex]\frac{45.6}{101.33} = 0.45 \ atm[/tex]
0.45 atmospheres
which compound contains both ionic and covalent bonds
Answer:
Any compound that contains a metal ion and a polyatomic ion would work. Polyatomic ions are covalently bonded non-metals that have some overall charge. Examples of common polyatomic ions include OH⁻ (hydroxide), NH₄⁺ (ammonium), and NO₃⁻ (nitrate). So answers to this question can be something like KOH (potassium hydroxide), but really, anything works if it contains a metal ion and a polyatomic ion.
True or false: The
louder you yell into a
megaphone in space,
the more likely it is for
the sound waves to
travel.
Answer:
True
Explanation:
This is known as a lapse rate. When you shout something to someone across the lake, the sound waves near the surface end up moving faster than the sound waves higher up. Since the speed is greatest near the ground, sound waves bend upward, causing the audio to be just out of ears reach.
What is a net ionic equation?
What type of reaction takes place when using this enzyme (endergonic or exergonic)?
lactase is the enzyme
Answer:
we do the best possible in our
give explanation ~~
Why are cloudy nights warmer than clear nights?
What is the atomic mass of an element that has 37 protons, 43 neutrons, and 36 electrons?
Answer:
the atomic mass of the element with 37 protons,43 neutrons and 36 electrons is 80
which bond shown are triple bonds
Answer:
Hey mate.....
Explanation:
This is ur answer.....
A triple bond is made of two pi bonds and one sigma bond. Examples of compounds with triple bonds include nitrogen gas, the cyanide ion, acetylene and carbon monoxide.
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If the energy of the H–H bond is 452 kJ/mol. The energy of the O=O bond is 598 kJ/mol. The energy of the O–H bond is 367 kJ/mol, which bond would be the strongest? Which bond would be the weakest?
Taking into account the bond energy, the O=O bond is the strongest and the O–H bond is the weakest.
The bond energy is the average total energy that would be released by the formation of a mole of chemical bonds, from their constituent fragments (all in the gaseous state).
In other words, the normal or standard bond enthalpy is defined as the change in enthalpy or heat released, under standard conditions of 1 atmosphere and 25ºC, that accompanies the reaction of formation of one mole of bonds from the isolated atoms in gaseous state.
The higher the bond energy, the stronger and more stable the bond will be.
So, taking into account all the previous, the O=O bond is the strongest and the O–H bond is the weakest.
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5. What is a chemical equation? What are the essentials of a chemical equation? What information is conveyed by a chemical equation? What are its limitations and how are they removed?
Answer:
A chemical equation is the symbolic representation of a chemical reaction in the form of symbols and formula. (i) It must refer to an actual chemical reaction. (ii) It should be molecular. For example, H, O, N should be written as H2, O2, N2. (iii) It should be balanced and conform to the law of conservation of matter.A chemical equation conveys both qualitative and quantitative information. Qualitatively, a chemical equation tells the names of the various reactants and the products.
Pls help if you only know the correct answer! Thanks! :)
Answer:
i think itd be an exothermic reaction
Explanation:
An exothermic process releases heat, causing the temperature of the immediate surroundings to rise.
chemistry, giving brainliest !
Answer:
20.03g
Explanation:
This is the formula for percentage yield:
Percentage yield = Actual Yield / Theoretical yield
Rearrange it to get the Actual yield, which would be:
Actual yield = Percentage yield (in decimal form) x Theoretical yield
We know that 75% of CO2 is produced as the percentage yield in a reaction and the theoretical yield for the mass we're supposed to find is 26.7 grams.
Percentage yield in decimal form: 0.75
Theoretical yield: 26.7g
Plug it in the equation
Actual yield = 0.75 x 26.7g
Actual yield = 20.03g
Describe a method you could use to carry out paper chromatography.
paper chromatography, in analytical chemistry, technique for separating dissolved chemical substances by taking advantage of their different rates of migration across sheets of paper..The method consists of applying the test solution or sample as a spot near one corner of a sheet of filter paper.
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Some tomato ketchup accidentally got onto a piece of white fabric. Your mother suggested that lemon juice, baking soda, or vinegar would be good for removing the tomato stain. Plan and design an experiment that can be used to investigate which of the three substances is most effective in removing the tomato stain.
1. Write a hypothesis for your investigation
2. Identify the dependent, independent, and controlled variables.
3. Outline a proposed method for the experiment you would conduct.
4. What data would be collected? Suggest a suitable way(s) for recording your data.
5. Identify ONE (1) possible source of error and ONE (1) precaution.
Please if you see this help me answer these questions.
Answer:
3... uhm I'm not sure it could 2
What is the chemical reaction by which organisms break down food
molecules for energy?
Answer:
cellular respiration
Explanation:
hope this helps :)
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