1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
butalik [34]
3 years ago
5

Which of the following numbers count as exact numbers and do not count when determining significant figures in a calculation? 1.

Density: 3.7 g/mL 2. Volume: 1000 mL/L 3. Length: 2.54 cm/in 4. Speed: 65.2 km/hr 5. Number: 14 aardvarks 6. Mass: 38.741 g
Chemistry
1 answer:
rewona [7]3 years ago
4 0

Answer :

(1) Density do not count as exact number.

(2) Volume count as exact number.

(3) Length count as exact number.

(4) Speed do not count as exact number.

(5) Number count as exact number.

(6) Mass do not count as exact number.

Explanation :

Exact numbers : It is a defined or integer value which comes from counting numbers of objects.

They have an infinite number of significant figures.

For example : 12 eggs in a dozen, 1000 g in a kilogram and 2.54 cm in an inch.

Now we have to determine the following numbers count as exact numbers.

(1) Density : 3.7 g/mL

Density do not count as exact number.

(2) Volume : 1000 mL/L

Volume count as exact number.

(3) Length : 2.54 cm/in

Length count as exact number.

(4) Speed : 65.2 km/hr

Speed do not count as exact number.

(5) Number : 14 aardvarks

Number count as exact number.

(6) Mass : 38.741 g

Mass do not count as exact number.

You might be interested in
Calculate the concentration of hydrochloric acid if 225.0 mL of this acid is neutralized by 120.0 mL of 2.0m sodium hydroxide A.
timurjin [86]
M1V1 = M2V2
225M1 = (2)(120)
225M1 = 240
M1 = 240/225 = 1.066 M C
5 0
3 years ago
1. Something must have mass in order to create change.
nignag [31]

These are three questions each with its complete answer.

Question 1. Something must have mass in order to create change.

A. True

B. False

Answer:

  • <u><em>False</em></u>

Explanation:

Two counter examples will prove that the statement is false.

  • light and fire

Neither light nor fire have mass, so they are not considered matter, but yet both can create changes.

Light is an electromagnetic wave, so it is energy, and as such it, of course, can cause some changes. One example are the chemical reactions, like photosynthesis, which require light to happen.

Ligth may also be described either as quanta named photons. Although photons behave like particles they do not have mass.

So, that example contradicts the statement that something must have mass in order to create change.

Fire also contradicts the statement. Fire is a manifestation of energy, it does not have mass, and sure you know how fire create changes in living and no living things.

Question 2. Powdered medicine fills a pill capsule. Which of the following is the best description of the state of the powder?

A. It is a solid because all powders are solid.

B. It is a gas because it takes up the entire volume of the pill capsule.

C. It is a liquid because it does not hold a definite shape.

Answer: the best description is the choice A:

  • A. It is a solid because all powders are solid.

Explanation:

Indeed, although sometimes the powder may be very fine (dust), yet it is not liquid or gas. Powders are always solid.

There are four main states of matter: solid, liquid, gas, and plasma.

Liquids are able to take the form of the container but do not occupy the entire container. Gases do occupy the entire container.

When powder is very fine it could resemble some properties of liquid, but the structure of powders is not crystaline, this is it is not an ordered arrangement. The structure of powders is an ordered arrangement, so powders are solids and not liquids.

It is easy to discard that a powdered medicine could be a gas, because it definetly do not occupy the entire volume of the pill capsule.

Question 3. Find an example of something that you do NOT know the state of. Describe it, and tell me your best guess of what state it is. Explain your guess.

Answer:

Two examples come to my mind:

  • A paste like Nutella or toothpaste

  • Wax of a candle

Explanation:

I will use the example of Nutella to complete the answer.

Nutella is not a gas because when you open the jar it will not escape and fill the room around it.

When you put Nutella in a plate it will not flow over the whole plate, is it a solid ? But yet you can spread it easyly over a cookie. Is it a liquid?

So, Nutella behaves like a solid until you apply some force over it and then it seems a liquid.

I would guess that pastes are solids because they should have an inner structure that keep the particles together.

If you do some research you will find that pastes are neither liquid nor solids, they are named gels. And gels may be seen as a dispersion of molecules of a liquid within a solid, i.e. in liquid particles dispersed in the solid medium

This sure meets the requirements of this question.

8 0
3 years ago
Taking your foot off of the gas pedal when you see a police car which of the Newton’s law
larisa [96]

Answer:

newton's third law of motion

Explanation:

it states about action and reaction when you see an action you take reaction like taking off your foot from the gas pedal

3 0
2 years ago
Description of horizon a
topjm [15]
I like that game Forza horizon

5 0
3 years ago
How many moles of potassium are in 78.20 g?
Fynjy0 [20]
The answer to this question would be: 2 mol

To answer this question, you need to know the molecular weight of Potassium. Molecular weight determines how much the weight of 1 mol of a molecule has. 
Potassium or Kalium molecular weight is 39.1 gram/mol. Then, 78.20gram of potassium should be: 78.20g/ (39.1g/mol)= 2 mol
7 0
3 years ago
Read 2 more answers
Other questions:
  • You have 9.494 grams of a diatomic gas being stored at STP in a 3.00 liter container. What is the gas?
    5·1 answer
  • I NEED HELP FAST!!!!! Can you tell me about examples of physical and chemical compounds of matter??? I have a DBA in a few minut
    15·1 answer
  • Definition for outcome variable
    7·1 answer
  • Why are only some minerals found as native minerals? For example, iron and aluminum are almost never found as native elements in
    7·1 answer
  • 1. Why would it be difficult to recycle polyvinyl chloride into plastic bags?
    14·2 answers
  • 1) Chemical analysis of a gaseous compound show its composition to be 36.4% carbon, 57.5% fluorine, and 6.1%
    10·1 answer
  • What causes climate change?
    13·2 answers
  • Hi!! please help! i have 20 mins to turn this in!! :))
    9·1 answer
  • Describe fractional distillation and explain what a fraction is?
    13·1 answer
  • Four cups of pure water are added to a 20-cup bowl of punch that is 75% juice. What percentage of the new punch is juice? Origin
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!