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
cestrela7 [59]
4 years ago
14

(Please someone help! This is chemistry)

Chemistry
1 answer:
Firlakuza [10]4 years ago
5 0

Answer:

0.00079

When you round 0.000789 to 2 significant figures you would get

0.00079

because the zeros are just place holders if they are right after the decimal and don't have other numbers between them

then 789 rounds up to 790, which is 79

Explanation:

You might be interested in
In the measurement 0.503 L , which digit is the estimated digit ?
AysviL [449]
The estimated digit is dependent on the least count of the instrument being used. If the least count is 0.1 and the reading is between two divisions of the least count, then the estimated digit will be in the tenths, or 0.1 place. In this case, the estimated digit is 3, meaning the least count is 0.001.
5 0
4 years ago
Explain why gases such as the oxygen found in tanks used as hospitals are compressed. why must care be taken to prevent compress
allochka39001 [22]

They are compressed so that a larger amount of gas can be stored in a smaller container. A greater mass confined to a smaller volume makes transporting and storing of gases easier. Increasing temperature increases pressure, and the cylinders might explode. Before compressed oxygen can be breathed, it must be decompressed.

7 0
3 years ago
Read 2 more answers
Do bases contain hydrogen ions (H+)
Dmitrij [34]

One definition of an acid is a molecule that can donate a H+ ion. So for example if you have an acid such as hydrochloric acid (HCl) in water, HCl will donate it's H+ to the H2O molecule, forming Cl- and H3O+.  

In contrast, a base is a molecule that accepts H+ ions. This means a base such as NH3 reacts with H2O to form OH- and NH4.

So when pH is measured, it is the ratio of H3O+ ions to OH- ions. If there are more H3O+ ions, you then know that there are more acidic molecules in the solution, since they must be giving away their H+ ions.  

So a solution with an acid in it will have more H3O+ ions (which can be described as H+ ions) in it. However, an acid by itself will have nothing to donate H+ ions to.

hope this helps also please make me the brainliest

6 0
4 years ago
State the law of conservation of mass
Katen [24]

It’s basically that’s any system that’s closed to all transfers of matter and energy the mass of the system has to remain constant over time because they can’t change meaning you can’t add or remove from it

8 0
3 years ago
A 5.325g sample of methyl benzoate, a compound in perfumes , was found to contain 3.758 g of carbon, 0.316 g of hydrogen, and 1.
Alexxandr [17]

<u>Answer:</u> The empirical and molecular formula of the compound is C_4H_4O and C_8H_8O_2 respectively

<u>Explanation:</u>

We are given:

Mass of C = 3.758 g

Mass of H = 0.316 g

Mass of O = 1.251 g

To formulate the empirical formula, we need to follow some steps:

  • <u>Step 1:</u> Converting the given masses into moles.

Moles of Carbon =\frac{\text{Given mass of Carbon}}{\text{Molar mass of Carbon}}=\frac{3.758g}{12g/mole}=0.313moles

Moles of Hydrogen = \frac{\text{Given mass of Hydrogen}}{\text{Molar mass of Hydrogen}}=\frac{0.316g}{1g/mole}=0.316moles

Moles of Oxygen = \frac{\text{Given mass of oxygen}}{\text{Molar mass of oxygen}}=\frac{1.251g}{16g/mole}=0.078moles

  • <u>Step 2:</u> Calculating the mole ratio of the given elements.

For the mole ratio, we divide each value of the moles by the smallest number of moles calculated which is 0.078 moles.

For Carbon = \frac{0.313}{0.078}=4.01\approx 4

For Hydrogen  = \frac{0.316}{0.078}=4.05\approx 4

For Oxygen  = \frac{0.078}{0.078}=1

  • <u>Step 3:</u> Taking the mole ratio as their subscripts.

The ratio of C : H : O = 4 : 4 : 1

The empirical formula for the given compound is C_4H_4O

For determining the molecular formula, we need to determine the valency which is multiplied by each element to get the molecular formula.

The equation used to calculate the valency is:

n=\frac{\text{Molecular mass}}{\text{Empirical mass}}

We are given:

Mass of molecular formula = 130 g/mol

Mass of empirical formula = 68 g/mol

Putting values in above equation, we get:

n=\frac{130g/mol}{68g/mol}=1.9\approx 2

Multiplying this valency by the subscript of every element of empirical formula, we get:

C_{(2\times 4)}H_{(2\times 4)}O_{(2\times 2)}=C_8H_8O_2

Hence, the empirical and molecular formula of the compound is C_4H_4O and C_8H_8O_2 respectively

4 0
3 years ago
Other questions:
  • Express the following concentration of solution in terms of molarity: 3.00 L of solution contains 1.75 mol of solute.
    5·1 answer
  • Which pair of metals produces the highest voltage and why
    5·1 answer
  • How many loads of laundry will each shift pay for if the cost per load rises to 8 quarters?
    8·1 answer
  • What is the value (in V) of Eºcell for the following reaction? Zn2+ (aq) + Pb (s) → Zn (s) + Pb2+ (aq)
    10·1 answer
  • A chemical reaction with a negative enthalpy change and a negative entropy change ________. A) Must be nonspontaneous Is not pos
    11·1 answer
  • How many valence electrons are present in this atom?
    14·1 answer
  • Suppose you wanted to monitor a pH change between 8.7 and 7.7. Which indicator would be most appropriate
    14·1 answer
  • What term describes the specific amount of time required for half of a radioactive substance to become stable
    6·1 answer
  • What is the molarity of a solution that contains 50.0g of NaOH (molar mass = 40 grams/mole) in 2.0L of solution?
    9·2 answers
  • 13.<br> Which contains the same number of molecules as 22.4 liters of N2 at STP?
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!