The half-life of thorium-227 is 18.72 days. How many days are required for three-fourths of a given amount to decay?

What mass of carbon monoxide must be burned to produce 175 kj of heat under standard state conditions?

Soloha48 [4]

When 2.50 g is burned then in oxygen then 1.25kj of heat is produced.

8 0

2 years ago

Read 2 more answers

May someone assist, please...? I don't know how to do chemistry work...

EastWind [94]

Answer:

1) 90.0 mL

2) 11.25 M

3) 0.477 M

4) 144 mL

Explanation:

The main formula that will be used for all these calculations is:

C₁V₁ = C₂V₂

C stands for concentration and V stands for volume and the subscripts 1 and 2 indicate an initial concentration or volume and a final concentration or volume.

For each problem, it's best to start by figuring out what you have and what you need to find. Figure out if you're looking for an initial value or a final value.

1) We need to find the initial volume. So, take what values you have and plug them in and then solve for whatever variable:

5.00 M · V₁ = 500.0mL · 0.900 M - divide by 5.00

C₁ = 90.0 mL

2) This time we're finding the initial concentration:

20.0mL · C₁ = 150.0mL · 1.50 M - divide by 20.0mL

C₂ = 11.25 M

3) Now we're finding the final concentration:

12.00mL · 3.50 M = 88.0mL · C₂ - divide by 88.0mL

C₂ = 0.477 M

4) Finally, we're looking for the final volume:

9.0mL · 8.0 M = 0.50 M · V₂ - divide by 0.50 M

V₂ = 144mL

6 0

3 years ago

A 1. 07 g sample of a noble gas occupies a volume of 363 ml at 35°c and 678 mmhg. Identify the noble gas in this sample. (r = 0.

Margaret [11]

The identity of the noble gas is the sample is Krypton

<h3>Ideal Gas law</h3>

From the question, we are to determine the identity of the noble gas in the sample

From the ideal gas equation, we have that

PV = nRT

∴ n = PV / RT

Where P is the pressure

V is the volume

n is the number of moles

R is the gas constant

and T is the temperature

From the given information,

P = 678 mmHg = 0.892105 atm

V = 363 mL = 0.363 L

R = 0.08206 L.atm/mol.K

T = 35 °C = 35 + 273.15 K = 308.15 K

Putting the parameters into the equation, we get

n = (0.892105 × 0.363)/ (0.08206 × 308.15)

n = 0.0128 moles

Now, we will determine the Atomic mass of the sample

Using the formula,

Atomic = Mass / Number of moles

Atomic mass of the substance = 1.07 / 0.0128

Atomic mass of the substance = 83.6 amu

The noble gas with the closest atomic mass to this value is Krypton.

Molar mass of Krypton = 83.798 amu

Hence, the identity of the noble gas is the sample is Krypton

Learn more on Ideal Gas law here: brainly.com/question/20212888

#SPJ12

4 0

1 year ago

When 33 g of CaO and 10 g of H2O react, how many grams of calcium hydroxide would you expect to be produced* Explain your answer

MrMuchimi

Answer:

41.44 g

Explanation:

First of all, we must put down the equation of the reaction;

$CaO + H2O ----->Ca(OH)2$

Number of moles of CaO = 33g/56 g/mol = 0.59 moles

Number of moles of H20 = 10g/18 g/mol = 0.56 moles

Since the reaction is in 1:1 mole ration, H2O is the limiting reactant

Hence;

mass of Ca(OH)2 produced = 0.56 moles * 74 g/mol = 41.44 g

7 0

2 years ago

Read 2 more answers

Sometimes you are given a measured amount of two or more reactants and asked how much product can be formed. Explain what steps

Westkost [7]

Explanation:

To solve this problem, follow these steps;

Obtain a balanced equation of the reaction and familiarize with the reactants and products.
Find the number of moles of the reacting species since they are the known matter in terms of quantity.
From the number of moles, determine the limiting reactant.
The limiting reactant is the one given in short supply.
Such reactant determines the extent of the reaction.
Compare the moles of this specie to that of the products using the balanced equation.
Obtain the mole of the desired product and find the mass or desired quantity.
simply work from the known specie to the unknown

learn more:

Number of moles brainly.com/question/13064292

#learnwithBrainly

4 0

3 years ago