The plastic straws were placed under the wooden block to

Calculate the pOH of a 0.0143 M NaOH solution at 25 ⁰C.

arsen [322]

Answer:

A.) 1.845

Explanation:

You can find the pOH using the following equation:

pOH = -log[OH⁻]

Since NaOH dissociates into 1 Na⁺ and 1 OH⁻, the concentration of both ions is 0.0143 M.

pOH = -log[OH⁻]

pOH = -log[0.0143]

pOH = 1.845

5 0

2 years ago

Could someone help me with this?

Varvara68 [4.7K]

Solving part-1 only

#1

KMnO_4

Transition metal is Manganese (Mn)

#2

Actually it's the oxidation number of Mn

Let's find how?

$\\ \tt\Rrightarrow x+1+4(-2)=0$

$\\ \tt\Rrightarrow x+1-8=0$

$\\ \tt\Rrightarrow x-7=0$

$\\ \tt\Rrightarrow x=+7$

x is the oxidation number

#3

Purple as per the color of potassium permanganate

#4

$\boxed{\begin{array}{c|c|c}\boxed{\bf Tube} &\boxed{\bf Charge} &\boxed{\bf No\:of\; electrons\: loss}\\ \sf 2 &\sf +6 &\sf 6e^-\\ \sf 3& \sf +2 &\sf 2e- \\ \sf 4 &\sf 4 &\sf 4e^-\end{array}}$

7 0

2 years ago

How do u get a girl to like u

garri49 [273]

You have to be romantic with her and give her presents and always say that she is right.

7 0

3 years ago

Read 2 more answers

Ammonia gas will react with oxygen gas to yield nitrogen monoxide gas and water vapor.

ruslelena [56]

Answer:

a) 0.168 moles O2

b) 9.50 grams O2

c) 0.01662 kg NO

d)88.9 %

Explanation:

Step 1: Data given

Molar mass of NH3 = 17.03 g/mol

Molar mass of O2 = 32 g/mol

Molar mass of NO = 30.01 g/mol

Molar mass of H2O = 18.02 g/mol

Step 2: The balanced equation:

4NH3 + 5O2 → 4NO + 6H2O

a. How many moles of ammonia will react with 6.73g of oxygen?

Calculate moles of oxygen = mass O2/ molar mass O2

moles oxygen = 6.73 grams / 32.00 g/mol = 0.210 moles

Calculate moles of NH3

For 4 moles of NH3 we need 5 moles O2 to produce 4 moles NO and 6 moles H2O

For 0.210 moles O2 we need 4/5 *0.210 = 0.168 moles O2

b. If 6.42g of water is produced, how many grams of oxygen gas reacted?

Calculate moles of H2O = 6.42 grams / 18.02 g/mol = 0.356 moles

Calculate moles of O2:

For 4 moles of NH3 we need 5 moles O2 to produce 4 moles NO and 6 moles H2O

For 0.356 moles H2O we'll need 5/6 * 0.356 = 0.297 moles O2

Calculate mass of O2 = moles O2 * molar mass O2

Mass O2 = 0.297 moles O2 * 32.00 g/mol = 9.50 grams O2

c. If the reaction uses up 9.43105 g of ammonia, how many kilograms of nitrogen monoxide will be formed?

Calculate moles of ammonia = 9.43105 grams / 17.03 g/mol =0.5538 moles

Calculate moles of NO:

For 4 moles of NH3 we need 5 moles O2 to produce 4 moles NO and 6 moles H2O

For 0.5538 moles of NH3 we'll have 0.5538 moles NO

Calculate mass of NO

Mass NO = 0.5538 moles * 30.01 g/mol = 16.62 grams = 0.01662 kg NO

d. When 2.51 g of ammonia react with 3.76 g of oxygen, 2.27 g of water vapor are produced. What is the percentage yield of water?

Calculate moles of NH3 = 2.51 grams / 17.03 g/mol = 0.147 moles

Calculate moles of O2 = 3.76 grams / 32 g/mol = 0.118 moles

Determine the limiting reactant

O2 is the limiting reactant, it will completely be consumed (0.118 moles)

NH3 is in excess. There will react 4/5 * 0.118 = 0.0944 moles

There will remain 0.147 - 0.0944 = 0.0526 moles

Calculate moles H2O: For 0.118 moles O2 we'll have 6/5 * 0.118 = 0.1416 moles H2O

Calculate mass H2O = 0.1416 moles * 18.02 g/mol = 2.552 grams H2O

Calculate % yield = (2.27/2.552)*100 % = 88.9 %

4 0

3 years ago

A patients blood is tested for growth hormone which has a molecular mass of 848.952g/mol. The test results show a normal concent

rusak2 [61]

Answer:

$\boxed{4.7\times 10^{-9}}$

Explanation:

Data:

MM = 848.952 g/mol

c = 4.0 x 10⁻⁶ g/L

V = 1 L

Calculations:

(a) Mass of growth hormone

$\text{Mass} = \text{1 L} \times \dfrac{4.0 \times 10^{-6} \text{ g}}{\text{1 L}} = 4.0 \times 10^{-6} \text{ g}$

(b) Moles of growth hormone

$\text{Moles} = 4.0 \times 10^{-6} \text{ g} \times \dfrac{\text{1 mol}}{\text{848.952 g}} = 4.7\times 10^{-9}\text{ mol}\\\\\text{There are $\boxed{\mathbf{4.7\times 10^{-9}}\textbf{ mol}}$ of growth hormone in 1 L of blood.}$

8 0

3 years ago