Answer:
Here is your Answer.......
Explanation:
The Watson and Crick's ball-and-stick model of DNA best illustrates the role of creativity in scientific discovery
Answer:
.081 g of O2
Explanation:
4Cr + 3O2 -----> 2Cr2O3
.175 g Cr x [1 mole / 52.0 g] x [2 moles Cr2O3 / 4 moles Cr] x [152 g / 1 mole] = .256 g of Cr2O3
.175 g Cr x [1 mole / 52.0 g] x [3 moles O2 / 4 moles Cr] x [32 g / 1 mole] = .081 g of O2
1.062 mol/kg.
<em>Step 1</em>. Write the balanced equation for the neutralization.
MM = 204.22 40.00
KHC8H4O4 + NaOH → KNaC8H4O4 + H2O
<em>Step 2</em>. Calculate the moles of potassium hydrogen phthalate (KHP)
Moles of KHP = 824 mg KHP × (1 mmol KHP/204.22 mg KHP)
= 4.035 mmol KHP
<em>Step 3</em>. Calculate the moles of NaOH
Moles of NaOH = 4.035 mmol KHP × (1 mmol NaOH/(1 mmol KHP)
= 4.035 mmol NaOH
<em>Step 4</em>. Calculate the mass of the NaOH
Mass of NaOH = 4.035 mmol NaOH × (40.00 mg NaOH/1 mmol NaOH)
= 161 mg NaOH
<em>Step 5</em>. Calculate the mass of the water
Mass of water = mass of solution – mass of NaOH = 38.134 g - 0.161 g
= 37.973 g
<em>Step 6</em>. Calculate the molal concentration of the NaOH
<em>b</em> = moles of NaOH/kg of water = 0.040 35 mol/0.037 973 kg = 1.062 mol/kg
Answer: +35
explanation: 30+35£~£
Answer:
0.0658 M
Explanation:
The reaction that takes place is:
Na₂SO₄(aq) + BaCl₂(aq) ↔ BaSO₄(s) + 2NaCl(aq)
First we <u>calculate the number of Na₂SO₄ moles</u>:
- 0.4000 g sample * 96.4/100 = 0.3856 g Na₂SO₄
- 0.3856 g Na₂SO₄ ÷ 142.04 g/mol = 2.715x10⁻³ mol Na₂SO₄
Now we <u>convert to moles of BaCl₂</u>:
- 2.715x10⁻³ mol Na₂SO₄ * 1 molBaCl₂/1 molNa₂SO₄ = 2.715x10⁻³ mol BaCl₂
Finally we divide by the volume to <u>calculate the molarity</u>:
- 41.25 mL ⇒ 41.25 / 1000 = 0.04125 L
- 2.715x10⁻³ mol BaCl₂ / 0.04125 L = 0.0658 M
