Answer:
Non-zero digits are always significant.
Any zeros between two significant digits are significant.
A final zero or trailing zeros in the decimal portion ONLY are significant. If a number ends in zeros to the right of the decimal point, those zeros are significant.
Explanation:
1.138 has 4 significant figures, which are 1, 1, 3 and 8. The numbers after the decimal point are decimals and are significant figures.
Enzymes help the process of _digestion.
Answer: Yes they help you digest foods in your stomach
Explanation:
If you need a refresh of them: Enzymes create chemical reactions in the body. They actually speed up the rate of a chemical reaction to help support life. The enzymes in your body help to perform very important tasks. These include building muscle, destroying toxins, and breaking down food particles during digestion.
what are the things used in soap? are they good or bad to our skin?
Answer: Your skin is your largest organ—22 square feet on average— Cleansers and body washes—might actually be doing us more harm than good, but, unfortunately, it absorbs harmful chemicals we put on it, too.
Explanation: Some are bad like scented body wash and hair stuff. But unscented is WAY better than scented, I learned that the hard way...
Which statement is true about a reaction represented by a chemical equation that shows energy as a reactant?

A.
It absorbs energy.

B.
It releases energy.

C.
It is a replacement reaction.

D.
It is a combustion reaction.
How many grams are in 2.5 moles of PO4?
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Answer:
35.50
Explanation:
There are two stable isotopes, 35Cl (75.77%) and 37Cl (24.23%), giving chlorine a standard atomic weight of 35.45
The sum of the atomic masses of all the atoms in a compound is called the
How many moles are in 5.4x1024 molecules of C4H2F7I, heptafluoro-1-iodobutane? Group of answer choices
Given :
Number of molecules of [tex]C_4H_2F_7I[/tex].
To Find :
How many moles are in given number of molecules.
Solution :
We know, in 1 moles of any element/compound contains [tex]6.022\times 10^{23}[/tex] at atoms/molecules.
So, number of moles in [tex]5.4\times 10^{24}[/tex] molecules are :
[tex]n = \dfrac{5.4\times 10^{24}}{6.022\times 10^{23}}\\\\n = 8.97 \ moles[/tex]
Therefore, number of moles are 8.97 .
The Earth's _____ provides protection from meteorite impacts by causing them to _____.
please leave a simple answer
Answer:
atmosphere, break up
Explanation:
Answer:
Atmosphere, break up
Explanation:
How many moles of sodium hydroxide are required to react completely with 23.1 moles of sulfuric acid?
H2SO4(aq) + NaOH(aq) = 2H2O(L) + Na2SO4(aq)
Select one:
a. 46.2 moles NaOH
b. 11.6 moles NaOH
c. 5.78 moles NaOH
d. 23.1 moles NaOH
Answer:
46.2 moles of NaOH are required.
Explanation:
Given data:
Moles of NaOH required = ?
Moles of H₂SO₄ = 23.1 mol
Solution:
Chemical equation:
H₂SO₄ + 2NaOH → 2H₂O + Na₂SO₄
Now we will compare the moles of NaOH with H₂SO₄.
H₂SO₄ : NaOH
1 : 2
23.1 : 2×23.1 = 46.2
Thus, 46.2 moles of NaOH are required.
What chemical process occurs in cells to release energy?
A.
Oxidation
B.
Respiration
C.
Pespiration
D.
Nutrition
Answer:
B. Respiration
Explanation:
cellular respiration is the process where cells use glucose (C6H12O6) and oxygen gas (O2) to make carbon dioxide (CO2) water (H2O) and ATP, which is energy
formula:
C6H12O6 + 6O2 -> 6CO2 + 6H20 + 38ATP
How do the different cycles of energy and matter on Earth interact with each other?
Answer:
Energy enters the biosphere as sunlight. Plants change this energy into chemical energy through the process of photosynthesis. Then, the energy is passed to organisms that eat the plants. Energy and matter are also passed between organisms when they eat one another.
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Why do covalent compounds tend to be squishy?
Answer:
Since they're easy to separate, covalent compounds have low melting and boiling points. 2) Covalent compounds are soft and squishy (compared to ionic compounds, anyway). The reason for this is similar to the reason that covalent compounds have low melting and boiling points. When you hit an ionic compound with something, it feels very hard
Explanation:
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A heat energy of 645 J is applied to a sample of glass with a mass of 28.4 g. Its temperature increases from –11.6 °C to 15.5 °C. Calculate the specific heat of glass.
Answer:838J/kg/K
Explanation:
use : Q= mS◇ T
7. Some products or processes claim to be "chemical free" or say "no chemicals added." Based on your understanding of chemistry, what are the arguments for and against such statements?
Please i need help
The meaning behind the statement is that the products does not contains any synthetic and harmful chemicals such as colourants, preservatives etc.
What are synthetic chemicals?All natural products or materials contains certain kind of chemicals which are naturally made in them. Such chemicals are natural chemicals and does not harm the living or causes any unwanted reaction.
The chemicals which are made by humans for specific purposes are called synthetic chemicals. Which can be of toxic and hazardous. Almost all materials we use everyday such as toothpastes, shampoo, food items, dyes, medicines and the fertilizers and pesticides we use in agriculture are all chemicals.
These chemicals helps in some way but they can be harmful to life in other way. Some products claim that they are chemical free, may true or not they intending to clear that the product does not contain any synthetic chemical except the required natural chemicals.
To find more about synthetic chemicals, refer the link below:
https://brainly.com/question/19938248
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In a molecule of calcium sulfide, calcium has two valence electron bonds, and a sulfur atom has six valence electrons. How many lone pairs of electrons are present in the Lewis structure of calcium sulfide? Also, state why.
A. one
B. two
C. three
D. four
E. none
There are 2 lone pairs
Further explanationGiven
a molecule of calcium sulfide
two valence electron of Calcium(Ca)
six valence electrons of Sulfur(S)
Required
number of lone pairs of electrons
Solution
Lewis structure shows the form of bonds that occur in the valence electrons of an element or compound
Valence electrons are electrons used in a chemical bond
To achieve stability, the element S needs 2 more electrons which are obtained from 2 electrons from the Ca element,
A lone pair electrons means refers to an unshared pair of electrons(not bonding to the other atoms)
Could you use filtration on a solution?
Answer:
No.
Explanation:
This is because a solution is a mixture with two substances that have already dissolved in each other and so there is no residue left. Filtration works such that part of the mixture has smaller particles that can pass through the membrane of the filter paper while the bigger particles get stuck onto the paper as residue. A solution has a uniform size particle throughout and thus filtration does not work for purifying a solution.
what happens when exhaled air passes through clear lime water?
Why is it important to pasteurize certain liquids?
Answer:
Pasteurization involves heating liquids at high temperatures for short amounts of time. Pasteurization kills harmful microbes in milk without affecting the taste or nutritional value (sterilization= all bacteria are destroyed).
Explanation:
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Answer:
Dilute acid + carbonate used in making the salt of copper sulfate.
Explanation:
In this experiment an insoluble metal oxide is reacted with a dilute acid to form a soluble salt.Copper(II) oxide, a black solid, and colourless dilute sulfuric acid react to produce copper(II) sulfate,giving a characteristic blue colour to the solution.
A working model used to test a design is called a
Answer:
A working model used to test a design is called a
stop
During the formation of ammonia, what mass of Hydrogen gas would be required to react completely with 42g of nitrogen gas?
Answer:
9 grams
Explanation:
Hope it can help you.....
Which elements are abundant in visible universe
Hydrogen is the most abundant element in the Universe; helium is second. However, after this, the rank of abundance does not continue to correspond to the atomic number; oxygen has abundance rank 3, but atomic number 8. All others are substantially less common.
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{calcium nuclear charge 20+}
{calcium atomic mass 40amu}
1) determine the number of charged particles in the nucleus of calcium atom then deduce the number of electrons
{given the relative charge of a proton =1+\m 1 nucleon = 1amu}
2) determine its mass number A
3) determine the competition of this calcium atom
Answer:
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Explanation:
Calcium has an atomic number of 20 and an atomic mass of 40
The mass number of an isotope is the sum of the number of protons and neutrons in the atomic nucleus. The atomic number is the number of protons. The calcium-40 isotope has a mass number of 40 , and an atomic number of 20 , therefore it has 20 protons.
What does eggshells change color under the influence of various liquids?
Answer:Adding calcium to chicken's food is going to make the eggshells firmer. Independent variable:
Explanation:
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A model of the water cycle was made by adding a small amount of water into an aquarium, covering the aquarium with a piece of glass, and placing a lamp over the glass cover to add heat. What does the lamp represent when comparing this model to the real-life water cycle?
( A)Clouds
( B)Precipitation
( C)The ocean
( D)The sun
Answer:
D the sun
Explanation:
The sun adds heat to make the water evaporate.
Answer:
B)
Explanation:
The sun causes evaporation by heat, the lamps bulb will get hot and be a model of the sun. We know this because heat evaporates water.
Which phrases describe sedimentary rock?
what is the net force of 4N 2N!!
Answer: 4 N-2 N=2 Nto the left. Change in motion: The box will move to the left. 7.)
Explanation: Please mark branliest.
n the diagram shown, when an object ‘X’ is brought near the ring shaped magnet, the magnet moves away from it. Four friends are discussing what they can say about X. Nikhil: X can be a piece of any metal. Shailaja: X can only be a piece of iron. Akash: X is definitely a magnet. Vinay: X can neither be a magnet or an iron piece. Who is correct?
Answer:
Akash
Explanation:
it could be a magnet with the same poles facing eachoher
What does the little ‘3’ in 2NH3 mean?
Answer:
It determines the number of molecules
Answer:
it means there are 3 hydrogen atoms in the compound.
how many grams are in 22.3 mole of Copper (II) Hydroxide?
Answer:
2180 g Cu(OH)₂
General Formulas and Concepts:
Chemistry - Atomic Structure
Reading a Periodic TableUsing Dimensional AnalysisExplanation:
Step 1: Define
22.3 mol Cu(OH)₂
Step 2: Identify Conversions
Molar Mass of Cu - 63.55 g/mol
Molar Mass of O - 16.00 g/mol
Molar Mass of H - 1.01 g/mol
Molar Mass of Cu(OH)₂ - 63.55 + 2(16.00) + 2(1.01) = 97.57 g/mol
Step 3: Convert
[tex]22.3 \ mol \ Cu(OH)_2(\frac{97.57 \ g \ Cu(OH)_2}{1 \ mol \ Cu(OH)_2} )[/tex] = 2175.81 g Cu(OH)₂
Step 4: Check
We are given 3 sig figs. Follow sig fig rules and round.
2175.81 g Cu(OH)₂ ≈ 2180 g Cu(OH)₂