PLS HELP ME, use the periodic table to write the electron configuration of selenium

Which of the following is not the same as 0.00684 kg?

olchik [2.2K]

kg and all the given units are units used to measure mass.

kg is the standard unit to measure mass

lets find the value of 0.00684 kg in all the given units

a. dkg

1 kg is equivalent to 100 decagram (dkg)

therefore 0.00684 kg is = 100 dkg/kg x 0.00684 kg = 0.684 dkg

this is not the given value therefore this choice is incorrect

b. 1 kg is equivalent to 1000 g

therefore 0.00684 kg = 1000 g/kg x 0.00684 kg = 6.84 g

this is the given value so this is correct

c. 1 kg is equivalent to 100 000 centigrams (cg)

therefore 0.00684 kg = 100 000 cg/kg x 0.00684 kg = 684 cg

this is the given value so this is also correct

d) 1 kg is equivalent to 1 000 000 mg

therefore 0.00684 kg = 1 000 000 mg/kg x 0.00684 kg = 6 840 mg

this too is correct

the incorrect answer is A. 0.0684 dkg

5 0

3 years ago

Read 2 more answers

Following the instructions in your lab manual, you have titrated a 25.00 mL sample of 0.0100 M KIO3 with a solution of Na2S2O3 o

vivado [14]

Answer:

For 1: The amount of potassium iodate that were titrated is $2.5\times 10^{-4}$ moles

For 2: The amount of sodium thiosulfate required is $1.25\times 10^{-4}$ moles

Explanation:

For 1:

To calculate the number of moles for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (in L)}}$

Molarity of $KIO_3$ solution = 0.0100 M

Volume of solution = 25 mL

Putting values in above equation, we get:

$0.0100M=\frac{\text{Moles of }KIO_3\times 1000}{25}\\\\\text{Moles of }KIO_3=\frac{0.0100\times 25}{1000}=0.00025mol$

Hence, the amount of potassium iodate that were titrated is $2.5\times 10^{-4}$ moles

For 2:

The chemical equation for the reaction of potassium iodate and sodium thiosulfate follows:

$2KIO_3+Na_2S_2O_3\rightarrow K_2S_2O_3+2NaIO_3$

By Stoichiometry of the reaction:

2 moles of potassium iodate reacts with 1 mole of sodium thiosulfate

So, 0.00025 moles of potassium iodate will react with = $\frac{1}{2}\times 0.00025=0.000125mol$ of sodium thiosulfate

Hence, the amount of sodium thiosulfate required is $1.25\times 10^{-4}$ moles

6 0

3 years ago

What mass of glucose would you need (in g) to have 0.8 mol, given that the molar mass of glucose is 180 g mol-1?

Verizon [17]

<h3>Answer: 144 g</h3>

Explanation:

Mass of glucose = moles × molar mass

∴ Mass of glucose = 0.8 mol × 180 g mol⁻¹

= 144 g

∴ the mass of glucose you need to have 0.8 mol of glucose = 144 g

5 0

2 years ago

(part 1 of 3) Copper reacts with silver nitrate through a single replacement. If 1.29 g of silver are produced from the reaction

ale4655 [162]

Answer:

See explanation.

Explanation:

Hello there!

In this case, according to the described chemical reaction, we first write the corresponding equation to obtain:

$Cu+2AgNO_3\rightarrow 2Ag+Cu(NO_3)_2$

Thus, we proceed as follows:

Part 1 of 3: here, since the molar mass of silver and copper (II) nitrate are 107.87 and 187.55 g/mol respectively, and the mole ratio of the former to the latter is 2:1, we can set up the following stoichiometric expression:

$m_{Cu(NO_3)_2}=1.29gAg*\frac{1molAg}{107.87gAg}*\frac{1molCu(NO_3)_2}{2molAg}*\frac{187.55gCu(NO_3)_2}{1molCu(NO_3)_2} \\\\m_{Cu(NO_3)_2}=1.12gCu(NO_3)_2$

Part 2 of 3: here, the molar mass of copper is 63.55 g/mol and the mole ratio of silver to copper is 2:1, the mass of the former that was used to start the reaction was:

$m_{Cu}=1.29gAg*\frac{1molAg}{107.87gAg}*\frac{1molCu}{2molAg}*\frac{63.55gCu)_2}{1molCu} \\\\m_{Cu}=0.380gCu$

Part 3 of 3: here, the molar mass of silver nitrate is 169.87 g/mol and their mole ratio 2:2, thus, the mass of initial silver nitrate is:

$m_{AgNO_3}=1.29gAg*\frac{1molAg}{107.87gAg}*\frac{2molAgNO_3}{2molAg}*\frac{169.87gAgNO_3}{1molAgNO_3} \\\\m_{AgNO_3}=2.03gAgNO_3$

Best regards!

5 0

3 years ago

The rays of the sun strike the Earth less directly during winter in the Northern Hemisphere?

noname [10]

The sun's rays hit the Earth at a extreme angle, which causes the days to become shorter, so yes, the sun's rays do hit the Earth at a extreme angle.

8 0

3 years ago