The alkene CH3 CHCH CH2 CH3 is named 2-butene. It is a four-carbon alkene with a double bond between the second and third carbon atoms in the chain. The name "2-butene" indicates the position of the double bond in the carbon chain. **

The skeletal formula of CH3 is simply a line representing the carbon atom with three hydrogen atoms attached to it. This is a simplified way of representing organic molecules where carbon atoms are not explicitly shown, and only the bonds and other atoms are depicted. In the case of CH3, the carbon atom is assumed to be at the end of the line with three hydrogen atoms attached to it. **

CH3 and H3C both represent a methyl group in organic chemistry, but the difference lies in the way they are written. CH3 is written with the carbon atom first, followed by the hydrogen atoms, while H3C is written with the hydrogen atoms first, followed by the carbon atom. Despite this difference in notation, both CH3 and H3C represent the same functional group in organic molecules. **

The gas heater may buzz due to a variety of reasons, such as a loose component within the heater, a malfunctioning fan motor, or a build-up of debris or dust in the system. Additionally, a clogged burner or gas valve could also cause the heater to buzz. It is important to have a professional technician inspect and diagnose the issue to ensure safe and proper functioning of the gas heater. **

Error code 018-0516 in Animal Crossing: New Leaf typically indicates a communication error between the game and the Nintendo 3DS console. This error can occur when there is a problem with the internet connection, such as a weak signal or network interference. To resolve this issue, try restarting your router, moving closer to the Wi-Fi source, or resetting your internet connection settings on the 3DS. **

The buzzing and humming sound from an electric convection heater is typically caused by the vibration of its internal components, such as the heating elements or the fan motor. When electricity flows through these components, it can cause them to vibrate, producing the buzzing and humming noise. Additionally, the expansion and contraction of the heater's metal casing as it heats up and cools down can also contribute to the noise. Overall, the buzzing and humming of an electric convection heater is a normal part of its operation and is not usually a cause for concern. **

No, the identity matrix is not an elementary matrix. An elementary matrix is a square matrix that can be obtained from the identity matrix by performing a single elementary row operation. The identity matrix is a special type of square matrix that has 1s on the main diagonal and 0s everywhere else. It cannot be obtained from the identity matrix by performing a single elementary row operation, so it is not considered an elementary matrix. **

Error code 018-0515 in Animal Crossing typically indicates a connectivity issue with the game's online features. This error code may appear when the game is unable to connect to the internet or when there are issues with the player's network connection. To resolve this error, players can try troubleshooting their internet connection, restarting their router, or contacting their internet service provider for assistance. Additionally, checking for any system or game updates may also help resolve the issue. **