In a simple covalent compound, which statement is TRUE

Which element increases its oxidation number in this reaction? 2Na + 2H2O → 2NaOH + H2

sammy [17]

Answer:

Sodium

Explanation:

-Gradpoint

6 0

4 years ago

If 24.6 grams of lithium react with excess water, how many liters of hydrogen gas can be produced at 301 Kelvin and 1.01 atmosph

andreev551 [17]

Answer: 43.3 l

Explanation:

1) Chemical equation:
2 Li(s) + 2 H₂O (l) → 2LiOH(aq) + H₂ (g)

2) Mole ratios:

2 mol Li : 2 mol H₂O : 2 mol LiOH : 1 mol H₂

3) Number of moles of Li that react

n = mass in grams / atomic mass = 24.6g / 6.941 g/mol = 3.54 moles

4) Yield

Proportion:

2 mol Li / 1 mol H₂ = 3.54 mol Li/ x

⇒ x = 3.54 mol Li × 1 mol H / 2 mol Li = 1.77 mol H₂

4) Ideal gas equation

PV = nRT ⇒ V = nRT / P

V = 1.77 mol × 0.0821 [atm×l / (mol×K)] × 301 K / 1.01 atm = 43.3 l

V = 43.3 l ← answer

7 0

4 years ago

A student measures the mass of a sample as 9.64 g. Calculate the percentage error, given that the correct mass is 9.80 g.

rosijanka [135]

Answer:

<h3>The answer is 1.63 %</h3>

Explanation:

The percentage error of a certain measurement can be found by using the formula

$P(\%) = \frac{error}{actual \: \: number} \times 100\% \\$

From the question

actual mass = 9.80 g

error = 9.80 - 9.64 = 0.16

We have

$p(\%) = \frac{0.16}{9.80} \times 100 \\ = 1.632653061...$

We have the final answer as

Hope this helps you

5 0

4 years ago

Helpp chemistry ..........

ValentinkaMS [17]

Half-life is the time it takes for the radioactive material's mass to decrease by half.

So, half of 96 is 48
half of 48 is 24
half of 24 is 12
half of 12 is 6

96->48->24->12->6

You count how many arrows (->) there is.
Which is 4

Then you use the 12 minutes the question gave you to do:
12 divided by 4
= 3

So, one half-life (Or the time it takes for the radioactive material's mass to decrease in half) is 3 minutes

and every 3 minutes it will decrease by half.

3 0

3 years ago

3.0 mL of 0.02 M Fe(NO3)3 solution is mixed with 3.0 mL of 0.002 M NaNCS and diluted to the mark with HNO3 in 10 mL volumetric f

Stella [2.4K]

Answer:

The $K_c$ for $[Fe(NCS)]^{2+}$ formation is $5.7\times 10^2$ .