What is the solution to the problem expressed to the correct number of significant figures?
7.21= ?
A. 1.688
OB.
1.69
O C.
1.7:
OD
1.70

Answers

Answer 1

Answer:

(102 900 ÷ 12) + (170 × 1.27) = 8800

Step 1. Evaluate the expressions inside the parentheses (PEMDAS)

102 900 ÷ 12 = 8575

170 × 1.27 = 215.9

In multiplication and division problems, your answer can have no more significant figures than the number with the fewest significant figures.

Thus, the underlined digits are not significant, but we keep them in our calculator to avoid roundoff error.

Step 2. Do the addition (PEMDAS).

  8575

+    215.9

= 8790.9

Everything that you add to an insignificant digit gives an insignificant digit as an answer.

Thus, the underlined digits are not significant.

We must drop them and round up the answer to 8800.

Explanation:


Related Questions

An ideal gas occupies a volume V at an absolute temperature T. If the volume is halved and the pressure kept constant, what will happen to it's temperature?



a. It will halve to T/2.


b. It will increase to 3T.


c. It will increase to 2T.


d. It will remain the same.

Answers

Answer:

It will be halve of T

Explanation:

V1 = V

T1 = T

V2 = ½V

T2 = x

V1/T1 = V2/T2

V/T = ½V/x

Vx = ½VT

2Vx = VT

2x = T

x = ½T

Four major bahiagrass varieties

Answers

12 bdhxhsbs shzhxjdjdbsjjs
common, argentine, pensacola, and paraguay

Witch event signals the birth of a star

Answers

Answer:

It's either C or D

Explanation:

I'm learning this too! :)

i am pretty sure D have a great rest of your day or night either one :)

OPEN ENDED QUESTION A chemistry student has a 5.001 g of CaCl2. How many moles of CaCl2 does the student have? (mm CaCl2 = 110.98 g)​

Answers

Answer:

0.04506 mol

Explanation:

For this problem, you need to convert grams to moles.  To do this, you need the molar mass, which is given.  Divide the mass by the molar mass to find the moles you have.

(5.001 g)/(110.98 g/mol) = 0.04506 mol

Our solar system formed from a
) a. huge disk of dust and gases
b.milky way and stars
c. sun and a moon

Answers

Our solar system formed about 4.5 billion years ago from a dense cloud of interstellar gas and dust. The cloud collapsed most likely due to a shockwave form a nearby exploding start called a supernova

Mix 200 g of copper at 100 °C with 1,000 g of water at 20 °C. Final temp. = 21.42°C a) How much heat energy (q) did the water gain? b) Now solve for the specific heat (c) of copper:

Answers

Answer:

a) [tex]Q_w=5941.3J[/tex]

b) [tex]C_{Cu}=0.378\frac{J}{g\°C}[/tex]

Explanation:

Hello there!

In this case, when a hot substance is mixed with a cold one, we can evidence how the hot one is able to heat up the cold one as it cools down. Thus, the net heat flow for this problem can be set up as shown below:

[tex]Q_{Cu}+Q_{w}=0[/tex]

Whereas the heats can be written in terms of mass, specific heat and temperatures:

[tex]m_{Cu}C_{Cu}(T_F-T_{Cu})+m_{w}C_{w}(T_F-T_{w})=0[/tex]

Thus, we proceed as follows:

a. Here we compute Qw:

[tex]Q_w=1,000g*4.184\frac{J}{g\°C}(21.42\°C-20\°C) \\\\Q_w=5941.3J[/tex]

b. Now, since this heat is equal to the negative of the heat contribution of copper (as it cools down), we can compute the specific heat of copper as shown down below:

[tex]C_{Cu}=\frac{-5941.3J}{200g(21.42\°C-100\°C)} \\\\C_{Cu}=0.378\frac{J}{g\°C}[/tex]

Best regards!

I need help I don’t get this

Answers

Answer:

Visit: gotit-pro.com

Explanation:

1) Convert pressure to atm
119 kPa x 1 atm/101 kPa = 1.18 atm

2) Convert temperature to Kelvin
35 + 273 = 308 K

3) Use PV=nRT and solve for V
(1.18 atm)(V)=(0.0972 mol)(0.0821)(308 K)

V = (0.0972 mol)(0.0821)(308 K) / (1.18 atm)

V = 2.08 L

9. Good insulator should be
(a) Fire proof
(b) Chemically inert
(c) Odourless in use
(d) All of the above
Ar​

Answers

Answer:

A fire proof

Explanation:

I hope this is help

what is atomic number of sodium​

Answers

Answer:

Explanation:

Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable isotope is ²³Na. The free metal does not occur in nature, and must be prepared from compounds.

Answer: Atomic number for sodium is 11

Symbol: Na

Melting point: 207.90°F (97.72°C)

The electronic configuration of sodium is 2, 8, 1

What is the mass, in amu, of an atom with one proton and two neutrons?

Answers

mass of proton mp=1.672621898e-27 kg and 1 amu=1.66053904e-27kg so it’s just divition (1.672621898e-27 / 1.66053904e-27) =1.007276 amu

Answer:

hi

Explanation:

hi

What do u mean by electronic configuration? What are basic requirements while writing electronic configuration of an element (atom) ?

Answers

Yes that is right I look it up thanks for the points

The basic requirement while writing the electronic configuration of an element (atom) is its atomic number.

Explanation:

The electronic configuration of an element is the distribution of its electrons in different energy levels around the atomic nucleus.It only requires an atomic number of an element to write its electronic configuration.The atomic number is equal to the number of protons in an atom and that is equal to the number of electrons.And the filling of electrons is done according to the Aufbau principle, the electrons will be first filled in the atomic orbitals with lower orbital energy before filling the atomic orbital with higher energy.The sequence of the atomic orbitals from lower energy to higher energy is:

    [tex]1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d...[/tex]

For example:

  The atomic number of gallium is 31, its electronic configuration will be:

   [tex][Ga]=1s^2 2s^2 2p^63s^2 3p^6 4s^2 3d^{10} 4p^1[/tex]

Learn more about an electronic configuration of an atom here:

brainly.com/question/11628377

brainly.com/question/18444398

In terms of valence electrons, explain why metals form positive ions.

Answers

Answer:

Explanation:

Metal elements form positively charged ions called cations because they are located on the left side of the periodic table These elements all have valence electrons in an s orbital. These electrons are relatively easy for the atom to lose to achieve a stable octet of electrons in its outermost energy shell.

Answer the multiple choice question below
Which physical property allows liquid-liquid mixtures to be separated using filtration?
I
A. Melting point
В.
Density
C.
Flammability
Evaporation

Answers

Answer:

flammability evaporation

2. How many carbon atoms would be in 2 MOLES of carbon?​

Answers

Answer:

In one mole of carbon , there are 6.02 × 1023 atoms. so in two moles , there will be twice that = 1.204× 1024.

A doctor tapes a patients knees with a hammer to test the reflex which can provide information about the condition of the _____

Answers

Answer:

lol this is what you get for not answering my question and stealing points

Explanation:

in____particles are in contact with each other.

Answers

Answer:liquid

Explanation:

The particles in a liquid usually are still touching but there are some spaces between them. The gas particles have big distances between them.

an artificial reef is intended to affect the ocean ecosystem by-​

Answers

Answer: B

Explanation:

i did the test

Give two examples of elevation.

Answers

Answer:

An example of elevation is a plane flying at 36,000 feet above the ground. An example of elevation is a pope being raised to the position of saint. An example of elevation is a ballet dancer leaping three feet in the air. ... At 8,850 m (29,028 ft), the summit of Mount Everest is the highest elevation on Earth.

Explanation:

please mark me brainly!

Which of the following is an
example of thermal energy?
A. turning on a lamp so you can read
B. rubbing your hands together to get warm
C. kicking a ball

Answers

Answer:

B. rubbing your hands together to get warm,

Explanation:

Rubbing your hands together warms them by converting work into thermal energy.

Hope it helps ;)

Answer:

I think its A

Explanation:

Because a lamp has a lightbulb and it produces wasted heat and is thermal energy

What type of energy transfer happens when you turn on a light bulb?​

Answers

Answer:In the case of an electric bulb, the electrical energy is converted to light and heat. The amount of electrical energy put into a bulb = the amount of light energy (desirable form) plus the heat energy that comes out of the bulb

Explanation:

Just trust me

Answer:

A type of energy

Explanation:

When thermal energy is removed from matter, what happens to the molecules?​

Answers

Answer:

Figure it out.

Explanation:

help fast plssssssssssssssssssss

Answers

Kinetic energy

That should be the answer

is photosynthesis part of chemical change?If yes can I have photosynthesis in chemical equation as chemical symbols​

Answers

Answer:

yes it is a chemical change

i have made it in above picture

.When sodium atoms (Na) and chlorine atoms (Cl) join to make sodium chloride, or table salt, they form an ionic bond. Using this information, which pair of elements is most likely to form an ionic bond?

potassium (K) and fluorine (F)
aluminum (Al) and aluminum (Al)
sulfur (S) and oxygen (O)
calcium (Ca) and neon (Ne)

Answers

Answer:

potassium (K) and fluorine (F)

Explanation:

Potassium is an alkali metal just like sodium and fluorine is a halogen just like chlorine. A metal and nonmetal will often join to form an ionic compound.

Aluminum, if it was going to bond to itself, would be a metallic bond.

Sulfur and oxygen are both nonmetals and would form a covalent bond.

Calcium would not bond with neon as neon is a noble gas.

Answer:

A) potassium (K) and fluorine (F)

Explanation:

got it right on time for learning :)

can someone explain in detail how molar mass, Avogadro's number, and volume are all connected through moles? Im so confused :(

Answers

Answer:

See Explanation

Explanation:

By definition, 1 mole is the mass of substance (or, formula mass in grams) containing 1 Avogadro's Number (N₀ = 6.02 x 10²³) of particles. That is ...

1 mole of hydrogen atoms (H) = 1.00794 grams

1 mole of molecular hydrogen (H₂) =  2.01588 grams

1 mole of any substance = 1 formula weight in grams

1 mole = 1 Avogadro's Number (N₀) = 1 formula weight in grams

In the concept of 'gas laws' 1 mole of any (all) gas at STP conditions ( => 0°C & 1 atmosphere pressure) occupies 22.4 Liters & is known as the 'molar volume' of a gas at STP. If the temperature &/or pressure change the volume will not be 22.4 Liters.

For reactions whose coefficients are balanced to the lowest whole number values (i.e., no fractional coefficients) the equation is known as the 'standard reaction' and conditions  are assumed to be STP and the coefficients of gas phase components indicate molar volumes. Example ...

Given   N₂(g) + 3H₂(g) => 2NH₃(g)  is assumed to be at 0°C; 1 Atm pressure.

Molecular Nitrogen = 1 molar volume = 22.4 Liters of N₂(g)

Molecular Hydrogen = 3 molar volumes = 3 x  22.4 Liters of H₂(g) = 67.2 Liters of H₂(g)

Molecular Ammonia = 2 molar volumes = 2 x 22.4 Liters of NH₃(g) = 44.8 Liters of NH₃

How many electrons are in the nucleus of an atom with 2 protons and 3 neutrons

Answers

Answer:

there'd be 2 electrons

Explanation:

number of electrons= number of protons

2 electrons
Because it is the same as 2 protons

Science activity 1.4.2​

Answers

You forgot to the pic again

How many lone pairs does this molecule have?

Answers

Answer:

Just 1 i.e., Option B.

Because except for top of the molecule, all other sides are filled with a letter meaning there is one free space.

Answer:

B

Explanation:

H .  +  H .   ----->  H:H            {":" represents a covalent bond, that is, a shared pair of electrons}

A Lewis structure is a convention used to represent the covalent bonding in a molecule.   Dots or lines are used to represent

valence electrons (electrons available for bonding).  The Lewis structure for the hydrogen molecule is as follows.

     H:H  or  H-H

A bonding pair is an electron pair shared between two atoms.

A nonbonding pair (lone pair, unshared pair) is a pair of electrons that remains on one atom and is not shared.

An independent variable is
a.
directly changed by the experimenter.
b.
manipulated by changes to the dependent variable.
C.
a variable that is kept constant.
d.
a variable that is used as a control.

Answers

Answer:

a. directly changed by the experimenter.

Explanation:

In the case of mathematical modeling, analytical modeling , and experimental sciences, the number of dependent variables based upon the amount of independent variables.

The dependent variables represent the result or outcome whose changes is being determined.

An independent variable expressed in the name form like experimental or expected variable, is a variable i.e. created in an experiment in order to verify the effect on a dependent variable

Therefore the option a is correct

i really need help, this is important to me, if not i get my harry styles tickets taken away and if that happens my life is over lol, i’m not saying it for sympathy i just REALLY need help

Answers

Explanation:

First Question

Group 18 elements. This is because the noble elements do not conduct electricity.

Second Question

Chewing in the mouth breaks food into small pieces

Third Question

How many atoms of each element are present in the molecule?

7 carbon atoms, 14 Hydrogen atoms and 1 oxygen atom

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