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natita [175]
3 years ago
9

For thousands of years, scientists didn’t know cells existed. What major invention helped open their eyes to the world of cells?

Chemistry
1 answer:
Snezhnost [94]3 years ago
5 0

Answer: microscope?

Explanation:

I'm not exactly sure it could even be an invension of some kind of test or experiment

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The primary method in which two connected objects transfer energy by heat flow is _____.
swat32
 Conduction is heat tranfer through physical contact. Hope this helps. :)
7 0
3 years ago
Read 2 more answers
The most common compound on earht is:
OlgaM077 [116]
The most common compound on earth is cellulose because it has enough energy to be the next source for biofuels. 
6 0
3 years ago
Complete the acid–base equation for the dissolution of the following compound into liquid HF solvent. The relevant pKa values ar
LenKa [72]

Answer:

The balanced chemical equation: NH₃ + 2 HF → NH₄⁺ + HF₂⁻

Explanation:

According to the Brønsted–Lowry acid–base theory, the acid- base reaction is a type of chemical reaction between the acid and base to give a conjugate acid and a conjugate base.

In this reaction, a Brønsted–Lowry acid loses a proton to form a conjugate base. Whereas, a Brønsted–Lowry base accepts a proton to form a conjugate acid.

Acid + Base ⇌ Conjugate Base + Conjugate Acid

The acid dissociation constant (Kₐ) <em>signifies the acidic strength of a chemical species.</em>

∵ pKₐ = - log Kₐ

Thus for a strong acid, Kₐ value is large and pKₐ value is small.

pKₐ (HF) = 3.2 → strong acid

pKₐ (NH₃) = 38 → weak acid

<u>The chemical reaction involved in the dissolution process:</u>

NH₃ + 2 HF → NH₄⁺ + HF₂⁻

In this acid-base reaction, the acid HF reacts with NH₃ base to give the conjugate base HF₂⁻ and conjugate acid NH₄⁺.

<u>HF (acid) donates a proton to form the conjugate base, HF₂⁻ ion. NH₃ (base) accepts a proton to form the conjugate acid. </u>

7 0
3 years ago
Sulfur trioxide, so3, is made industrially in enormous quantities by combining oxygen and sulfur dioxide, so2. what amount (mole
DedPeter [7]

The answer is 37.5 moles

The explanation:

1- when we have the mass of SO3 in Kg so, first we have to convert it to grams:

mass = 3 * 1000 = 3000 g

2- we need to get the molar mass of SO3 :

molar mass of SO3 = 32 + (16*3)

= 80 g/mol

3- then we can use this formula to get number of moles:

moles = mass / molar mass

= 3000 g / 80 g/mol

= 37.5 moles

6 0
3 years ago
Write the formula for lead oxide.
serious [3.7K]

Answer:

<h2>Lead(II) oxide</h2>

Explanation:

<h3>Lead(II) oxide, also called lead monoxide, is the inorganic compound with the molecular formula PbO. PbO occurs in two polymorphs: litharge having a tetragonal crystal structure, and massicot having an orthorhombic crystal structure. Modern applications for PbO are mostly in lead-based industrial glass and industrial ceramics, including computer components. It is an amphoteric oxide.[3]</h3>

  • IUPAC name
  • Lead(II) oxide

  • Other names
  • Lead monoxide
  • Litharge
  • Massicot
  • Plumbous oxide
  • Galena

<h2> Preparation</h2><h3>PbO may be prepared by heating lead metal in air at approximately 600 °C (1,100 °F). At this temperature it is also the end product of oxidation of other oxides of lead in air:[4]</h3><h3>Thermal decomposition of lead(II) nitrate or lead(II) carbonate also results in the formation of PbO:</h3>

<h3>2 Pb(NO</h3><h3>3)</h3><h3>2 → 2 PbO + 4 NO</h3><h3>2 + O</h3><h3>2</h3><h3>PbCO</h3><h3>3 → PbO + CO2</h3><h3>PbO is produced on a large scale as an intermediate product in refining raw lead ores into metallic lead. The usual lead ore is galena (lead(II) sulfide). At a temperature of around 1,000 °C (1,800 °F) the sulfide is converted to the oxide:[5]</h3>

<h3>2 PbS + 3 O</h3><h3>2 → 2 PbO + 2 SO2</h3><h3>Metallic lead is obtained by reducing PbO with carbon monoxide at around 1,200 °C (2,200 °F):[6]</h3>

<h3>PbO + CO → Pb + CO2</h3>

pls brainlest meh

5 0
2 years ago
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