Question 1

Blockchain vs chain?

Accepted Answer

'Chain' is the linked sequence of blocks. 'Blockchain' in normal use means the whole system: data structure plus network, rules, consensus and incentives.

Question 2

Coin vs token?

Accepted Answer

A coin is the network's native asset used to pay fees (ETH, BTC). A token is contract-managed state on top of a network (for example an ERC-20 balance).

Question 3

Mainnet vs testnet?

Accepted Answer

Mainnet carries real economic value. A testnet like Sepolia is functionally similar but its coin has no monetary value and is used for development.

Question 4

Wallet vs account?

Accepted Answer

A wallet is software holding keys and signing. The account is on-chain state (balance, nonce, code) addressed by a public identifier.

Question 5

Node vs validator?

Accepted Answer

A node stores and verifies chain data and relays messages. A validator (Ethereum) or miner (Bitcoin) additionally proposes or attests to blocks. Every validator runs a node; most nodes are not validators.

Question 6

RPC vs blockchain?

Accepted Answer

RPC is an API endpoint you use to talk to a node. It is access infrastructure, not the chain.

Question 7

Explorer vs blockchain?

Accepted Answer

An explorer is an indexed website reading chain data. It is a convenient view, not the source of truth.

Question 8

Gas vs ETH?

Accepted Answer

Gas measures computational work. ETH pays for it: fee = gas used × effective gas price.

Question 9

Hash vs encryption?

Accepted Answer

Hashing is one-way, keyless and fixed-length. Encryption is reversible with a key. They are not interchangeable.

Question 10

Private key vs password?

Accepted Answer

A password authenticates you to a service that can reset it. A private key mathematically authorises spending and cannot be reset or recovered by anyone.

Question 11

PoW vs mining reward?

Accepted Answer

Proof-of-work is the costly search that makes block production expensive. The reward (subsidy plus fees) is the incentive to pay that cost.

Question 12

PoW vs faucet mining?

Accepted Answer

Some faucets make your browser do small proof-of-work as anti-abuse. That is unrelated to a chain's consensus — Ethereum Sepolia uses proof-of-stake.

FAQ

General

BCM-C01 · Why Blockchain Exists

FAQ

General

Blockchain vs chain?

Coin vs token?

Mainnet vs testnet?

Wallet vs account?

Node vs validator?

RPC vs blockchain?

Explorer vs blockchain?

Gas vs ETH?

Hash vs encryption?

Private key vs password?

PoW vs mining reward?

PoW vs faucet mining?

Bitcoin PoW vs Ethereum PoS?

UTXO vs account model?

Block vs transaction?

What is the mempool?

What is a confirmation?

What is a fork?

What is a Merkle root?

What is a smart contract?

EOA vs contract account?

Is BCM crypto trading training?

BCM-C01 · Why Blockchain Exists

Is blockchain data encrypted?

Is hashing the same as encryption?

Is the mempool one global list?

Does every blockchain need a public cryptocurrency?

If a block takes 40 minutes, is it rejected?