an atom has 79 protons, 78 electrons and a mass number of 118. how many neutrons does this atom have
Answer:
39
Explanation:
Electrons weigh almost nothing, so their mass doesn't really matter for these types of problems. Just subtract 118-79 to find the remaining mass which is for the neutrons.
Mass and energy are conserved
Question 16 options:
A)
only in chemical changes.
B)
in chemical changes and physical changes.
C)
always in physical changes and sometimes in chemical changes.
D)
only in physical changes.
Question 17 (5 points)
Which of the following can't be broken down any further chemically?
Question 17 options:
A)
Compounds
B)
Elements
C)
Matter
D)
Molecules
Question 18 (5 points)
A/an _______ is the smallest unit of matter that has the characteristics of a chemical element.
Question 18 options:
A)
atom
B)
proton
C)
molecule
D)
electron
Question 19 (5 points)
The distance between consecutive peaks or troughs in a wave is
Question 19 options:
A)
frequency.
B)
displacement.
C)
amplitude.
D)
wavelength.
Question 20 (5 points)
The phase transition of dry ice (frozen carbon dioxide) to gas is an example of
Question 20 options:
A)
condensation.
B)
sublimation.
C)
deposition.
D)
vaporization.
Explanation:
16 A. 17C matter 18C molecule 19D wavelength 20 C deposition
Isotopes have
Question 1 options:
A)
different numbers of both protons and neutrons in their nuclei.
B)
a different number of neutrons in their nuclei.
C)
a different number of protons in their nuclei.
D)
a different number of electrons.
Question 2 (5 points)
An aqueous solution
Question 2 options:
A)
must contain three or more substances.
B)
is a single-phase heterogeneous mixture.
C)
has water as the solvent.
D)
has water as the solute.
Question 3 (5 points)
Which of the following is a homonuclear diatomic molecule?
Question 3 options:
A)
NH3
B)
CO
C)
2CO2
D)
H2
Question 4 (5 points)
Given a container of a solution of 5% HCl, all samples tested from this same bottle will have the same mass ratio of hydrogen to chlorine. This is an application of
Question 4 options:
A)
the law of conservation of energy.
B)
the law of multiple proportions.
C)
the law of conservation of mass.
D)
the law of constant composition.
Question 5 (5 points)
Elements in the same period
Question 5 options:
A)
have the same principal quantum number.
B)
form bonds with the same type of elements.
C)
have the same number of valence electrons.
D)
have the same number of protons.
Question 6 (5 points)
Which of the following contribute(s) to most of the mass of an atom?
Question 6 options:
A)
Neutrons only
B)
Protons and neutrons
C)
Protons and electrons
D)
Protons only
Question 7 (5 points)
In a certain chemical reaction, the bonds of the products contain more energy than the bonds of the reactants. For the reaction to occur, which of the following best describes what occurred?
Question 7 options:
A)
Energy was released, so the reaction is endothermic.
B)
Energy was released, so the reaction is exothermic.
C)
Energy was added, so the reaction is endothermic.
D)
Energy was added, so the reaction is exothermic
Question 8 (5 points)
A solution
Question 8 options:
A)
is a single-phase homogeneous mixture.
B)
must contain water.
C)
is always a liquid.
D)
can contain more than two phases.
Question 9 (5 points)
Which of the following is true of alloys?
Question 9 options:
A)
They can only be composed of metals.
B)
They must be held together by chemical bonds.
C)
They're liquid solutions.
D)
They must contain a metal.
Question 10 (5 points)
Which of the following best describes an atomic number? An element's identity is defined by its atomic number; this means it represents the number of
Question 10 options:
A)
electrons in the element.
B)
neutrons in its nucleus.
C)
protons plus neutrons in its nucleus.
D)
protons in its nucleus.
Question 11 (5 points)
Electrons in the outermost shell of an atom that are available to bond with the electrons of other atoms are
Question 11 options:
A)
cations.
B)
free electrons.
C)
valence electrons.
D)
anions.
Question 12 (5 points)
Main group elements have valence electrons in which suborbitals?
Question 12 options:
A)
d and f
B)
s and p
C)
p and f
D)
s and d
Question 13 (5 points)
Molecules have
Question 13 options:
A)
only kinetic energy.
B)
only potential energy.
C)
both potential and kinetic energy.
D)
neither kinetic nor potential energy.
Question 14 (5 points)
The majority of elements are
Question 14 options:
A)
metalloids.
B)
nonmetals.
C)
metals.
D)
inert.
Question 15 (5 points)
A student found the mass of an object to be 26.5 g. To find the volume, the student submerged the object in a graduated cylinder of water. Submerging the object in the water in the graduated cylinder increased the water level by 24.1 mL. The density of the object is
Question 15 options:
A)
1.0906 g/mL.
B)
0.909 g/mL.
C)
1.10 g/mL.
D)
1.1 g/mL.
Question 16 (5 points)
Mass and energy are conserved
Question 16 options:
A)
only in chemical changes.
B)
in chemical changes and physical changes.
C)
always in physical changes and sometimes in chemical changes.
D)
only in physical changes.
Question 17 (5 points)
Which of the following can't be broken down any further chemically?
Question 17 options:
A)
Compounds
B)
Elements
C)
Matter
D)
Molecules
Question 18 (5 points)
A/an _______ is the smallest unit of matter that has the characteristics of a chemical element.
Question 18 options:
A)
atom
B)
proton
C)
molecule
D)
electron
Question 19 (5 points)
The distance between consecutive peaks or troughs in a wave is
Question 19 options:
A)
frequency.
B)
displacement.
C)
amplitude.
D)
wavelength.
Question 20 (5 points)
The phase transition of dry ice (frozen carbon dioxide) to gas is an example of
Question 20 options:
A)
condensation.
B)
sublimation.
C)
deposition.
D)
vaporization.
I WILL GIVE BRAINLIEST IF YOU CAN ANSWER THEM
Answer:
b
Explanation:
dueto isotopes haveno thesame neutral numbee hence b iscorrect
Answer:
b
Explanation:
The sulfuric acid–catalyzed reaction of isopentyl alcohol with acetic acid to form isopentyl acetate is performed. This reaction does not proceed to completion. After the reaction is heated under reflux for an hour, the product mixture is washed with aqueous sodium bicarbonate solution, and the organic layer is thoroughly dried. A distillation of the organic layer is then performed. Given the boiling points listed below, select the compound that will distill first.
Compound Boiling point, ℃
acetic acid 118
isopentyl acetate 142
isopentyl alcohol 130
sulfuric acid water 290
Answer:
The correct option is acetic acid
Explanation:
Distillation is the process of separating a mixture of substances based on differences in boiling points. During distillation, the compound with the lowest/least boiling point is distilled and collected first and then the one with the next least boiling point and it goes on like that.
From the explanation above, acetic acid has the least boiling point (in the organic layer) with 118°C and thus will distill first. This is then followed by isopentyl alcohol (130°C) and then isopentyl acetate (142°C) and finally sulfuric acid water (290°C).
what is the formula for zinc sulfide
Answer:
the formula for zinc sulfide is b. ZnS
How many grams of lithium hypochlorite (LiClO) are there in 0.649 mol ?
Answer:
37.9 or 38 grmas approximately
Which of the following is a process that changes the composition of rocks from one material to another? (3 points) a Erosion b Deposition c Physical weathering d Chemical weathering
Answer:
ERosion i think
Explanation:
Answer:
Deposition
Explanation:
I hope you have a nice day(:
The melting and boiling points of a group of elements decrease as you go down the group, while their reactivity increases.
a.. Are the elements from the first group or the second last group of the Periodic Table?
b ..Does this group consist of metals, metalloids, non-metals or a mix?
c.. Identify two elements in this group.
Answer:
a) first group
b) metals
c) K - potassium, Li - lithium
Explanation:
a) they are the alkali metals
b) they're alkali metals lol
c) just look at a periodic table :P
A black bear can run 35.0 mph how long will it take to run 1.95 x 10^4?
A. 129
B. 0.360
C. None of the above
D. 0.106
E. 13
Answer:
The correct answer is C. None of the above.
Explanation:
To determine how long the black bear will run, the distance it will travel must first be determined. Thus, the proposed calculation must be solved.
1.95 x 10 ^ 4
1.95 x 10 x 10 x 10 x 10
19.5 x 10 x 10 x 10
195 x 10 x 10
1950 x 10
19500
Thus, the bear will run 19,500 miles, so, running at 35 mph, it will take about 557 hours to run that distance (19,500 / 35).
What is the molecular geometry of the atoms bonded to the carbon atom indicated with arrow I in this structure of caffeine?
Answer:
Trigonal planar
Explanation:
If we look at the carbon atom indicated I in the image, we will discover that it is a carbon atom that is bonded to a nitrogen atom via a double bond.
Recall that an sp2 hybridized carbon atom has a trigonal planar geometry. When a carbon atom is sp2 hybridized, it is in a trigonal planar geometry as we can clearly see from the image.
Sodium chloride can be used to preserve meat because
Answer:
Salt is effective as a preservative because it reduces the water activity of foods. .
How do I find the hydrated formula?
Answer:
In order to determine the formula of the hydrate, [Anhydrous Solid⋅xH2O], the number of moles of water per mole of anhydrous solid (x) will be calculated by dividing the number of moles of water by the number of moles of the anhydrous solid (Equation
Explanation:
Lollll I need help with this question
Answer:
Waves are any vibration that transfers energy from place to place.
Explanation:
IM NOT SURE ABOUT THE VIBRATION BIT BUT I AM ABOUT THE ENERGY
Which pair of elements are most likely to form a molecular compound?
Nitrogen and Hydrogen
Calcium and Copper
Chlorine and Neon
Please help! I will mark brainliest if correct!
Answer: Two nonmetals.
Explanation:
Answer:The only pair of nonmetals is sulfur and fluorine.
Explanation:The pair of elements most likely to form a molecular compound with each other are two nonmetals.
__Hgo > __Hg + __O2?
Hg + O2 → HgO
✅Word equation: Mercury + Oxygen gas → Mercury (II) oxide
✅ Type of Chemical Reaction: For this reaction we have a combination reaction.
✅ Balancing Strategies: To balance this equation it's probably easiest to begin by changing the coefficient in front of the HgO.
This is a combination reactions because the mercury (Hg) plus the oxygen gas (O2) come together to form the Mercury (II) oxide (MgO).
Hint-1
Hint-2
IamSugarBee
The state of matter of a material depends on its
O A) density
OB) temperature
O C) volume
OD) weight
Answer:
Tempature
Explanation:
Matter can move between any two states (or phases) of matter depending on the pressure and temperature conditions. ... The temperature of the melting and boiling points depend on the identity of the substance and the atmospheric pressure.
Also apex.
Answer:
temperature
Explanation:
an example here
ice
when its cold ice tends to stay as a solid but as the temperature rises the ice melts and turns into a liquid... with more heat the water will turn into gas
The mass of an object is 13.76 g. the volume of the object is 2.83 ml. what is the density of the object to the correct number of significant figures?
Answer:
D ≈ 4.86 g/mL
Explanation:
Density = Mass over Volume
D = m/V
Step 1: Define variables
m = 13.76 g
V = 2.83 mL
D = unknown
Step 2: Substitute and Evaluate for Density
D = 13.76 g/2.83 mL
D = 4.8621908127208480565371024734982 g/mL
Step 3: Simplify
We are given 3 sig figs.
4.8621908127208480565371024734982 g/mL ≈ 4.86 g/mL
What is the volume of 26.1 g of a substance if the density of the substance is 0.28 g/mL?
Answer:
It is 93.2
Explanation:
It's that answer because if you divide volume and density that's what you get
What is the correct order of star colors from hottest to coolest?
white, yellow, red, blue
yellow, orange, white, red
red, orange, yellow, blue-white
blue, white, yellow-white, orange
Answer: The answer is blue, white, yellow-white, orange.
Explanation: These are the two basic reasons for different star colors:
Temperature – cooler stars are red, warmer ones are orange through yellow and white. The hottest stars shine with blue light
Age – As a star ages it produces different chemicals which burn at different temperatures. We can use a star’s color to show its relative age
Answer:
OR D
Explanation:
D on edge 2020
how did domestication of early crops start?
Answer:
In the Fertile Crescent in the Middle East, cereal crops were first domesticated about 11,000 years ago. Generally, the first domesticated crops were annuals with big seeds or fruits. ... Humans began to transition from a hunter-gatherer culture to a settled farming society as domestication took place.
Please mark me brainliest!
Hope this helps God bless!
which gas is the most dense under standard temperature and pressure?
A. H2
B. Ne
C. Ar
D. O2
Answer:
I think it's b: ne
Explanation:
its just a wild guess
Order: Vitamin K (Aquamephyton) 1 mg IM x 1 dose Newborn: Weight 4 kg Supply: 10mg/mL vial How many mLs would be given
Answer:
Volume(ml) of drug required = 0.1 ml
So, medicine is safe for this child.
Explanation:
Given:
Desired dose (D)= 1 mg
Dose in hand (H) = 10 mg
Quantity (Q) = 1 ml
Computation:
Volume(ml) of drug = [Desired medicine / medicine in hand] Quantity.
Volume(ml) of drug required = [1/10]1
Volume(ml) of drug required = 0.1 ml
So, medicine is safe for this child.
What type of bond is present between Magnesium and Fluoride in MgF2?
Answer: Ionic Bond
Explanation:
Ionic compounds are created by bonding a metal and non-metal
Mg is a metal
Fluoride is a non-metal
Write the balanced chemical equation for the decomposition of sulfur trioxide to sulfur dioxide and
oxygen.
Answer:
The balanced equation is 2SO2+O2→2SO3 .
How many grams of F are in 225 g CaF2?
Answer:
109.575
Explanation:
Which of the following molecules has a trigonal pyramidal shape?
CO
Ni ---CO
A.
СО
OBCI-S c
Xeo
O.
O C.
0-N
Answer:
Xeo
Explanation:
A is the molecules with the trigonal pyramid shape
Which sample matter is a pure substance
Answer:
Explanation:
If you have options, could you please tell me so I can further help you. If you just need an example then
Examples of pure substances include iron, steel, and water
Hope this helps (:
Answer
These are the following answers
A) zinc oxide
B) sugar dissolved in water
C) pond water
D) soil
Explanation:
Which of the following is true for polar jet streams?
They bring cool air.
They bring warm air.
They blow at the equator.
They blow from north to south.
Answer:
A: They bring cool air.
Explanation:
Took the test and got it correct. :)
Jet streams are fast flowing meandering air currents. Polar jet streams bring cool air through the atmosphere. Polar jets meet subtropical jets at some regions.
What are polar jet streams ?The polar jet stream, which travels through the lower layers of the atmosphere in the Northern Hemisphere, is a swiftly moving band of westerly winds.
The confluence of warm air ascending from the tropics and cold air masses descending from the arctic produces the jet. The denser cold air lowers and deflects the warmer air areas north, creating deep troughs and steep ridges that give the jet stream its wavy appearance.
As pockets of cold air intermittently sneak down from the Arctic, this pattern spreads across the mid-latitudes of North America, Europe, and Asia, producing opposing waves and flows that speed eastward due to the earth's rotation.
Find more on jet streams:
https://brainly.com/question/885071
#SPJ2
Which statement best describes balancing equations and the law of conservation of mass?
O There are more atoms in the reactants than in the products, and the total mass is the same in the
reactants and in
the products
O The number of atoms is the same in the reactants and in the products, and the total mass is the same in the
reactants and in the products
O There are fewer atoms in the reactants than in the products, and the total mass is less in the reactants than in the
products
There are more atoms in the reactants than in the products, and the total mass is higher in the reactants than in
Toms
the products
Answer:
The number of atoms is the same in the reactants and in the products, and the total mass is the same in the reactants and in the products.
The statement best describes balancing equations and the law of conservation of mass is the number of atoms is the same in the reactants and in the products, and the total mass is the same in the reactants and in the products. Therefore, option B is correct.
What is the law of conservation of mass ?According to the law of conservation of mass or principle of mass conservation, any system that is closed to all transfers of matter and energy must maintain a constant mass over time since the system's mass cannot vary and neither more nor less amount can be added or subtracted.
This law states that no matter what physical or chemical change occurs, the overall mass of the products and reactants remain identical.
Understanding and producing different chemical reactions depend heavily on this law. Researchers might anticipate how much the result would be if they knew the identities and quantities of the reactants for each reaction.
Thus, option B is correct.
To learn more about the law of conservation of mass, follow the link;
https://brainly.com/question/20635180
#SPJ6
Isotopes have
Question 1 options:
A)
different numbers of both protons and neutrons in their nuclei.
B)
a different number of neutrons in their nuclei.
C)
a different number of protons in their nuclei.
D)
a different number of electrons.
Question 2 (5 points)
An aqueous solution
Question 2 options:
A)
must contain three or more substances.
B)
is a single-phase heterogeneous mixture.
C)
has water as the solvent.
D)
has water as the solute.
Question 3 (5 points)
Which of the following is a homonuclear diatomic molecule?
Question 3 options:
A)
NH3
B)
CO
C)
2CO2
D)
H2
Question 4 (5 points)
Given a container of a solution of 5% HCl, all samples tested from this same bottle will have the same mass ratio of hydrogen to chlorine. This is an application of
Question 4 options:
A)
the law of conservation of energy.
B)
the law of multiple proportions.
C)
the law of conservation of mass.
D)
the law of constant composition.
Question 5 (5 points)
Elements in the same period
Question 5 options:
A)
have the same principal quantum number.
B)
form bonds with the same type of elements.
C)
have the same number of valence electrons.
D)
have the same number of protons.
Answer:
question 1 answer is b
Explanation:
istopes equal to same atomic number but different mass number