What would happen if Venus was hit by a Chicxulub-like meteor? Would the dense atmosphere and high surface pressure and temperature lead to a different result compared to what happened here on Earth?
Question: Would the dense atmosphere and high surface pressure and temperature lead to a different result compared to what happened here on Earth?
Short Answer: No. There will not be any significant difference between impact on Earth and Venus by the Chicxulub impactor
The Chicxulub crater is a large asteroid-impact that is estimated to be caused by an asteroid named Chicxulub, that the crater was 150 kilometers wide in diameter (to be specific the impactor is just 11 kilometer wide), and its impact on Earth is the second known largest impact in Earth's history. Talking about the scenario of its impact on Venus, there are a lot of factors affecting the intensity of impact, the pressure, the angle of impact and also the Gravity of Venus is very similar to Earth but its atmosphere is incredibly dense compared to Earth, so like @CarlWitthoft said in the comment, the impact-velocity on Venus' surface will be less (slightly?) compared to what it did on Earth. Most of the debris caused on the Venus will tend to move back to space, but its gravity and its dense atmosphere will again put the debris back to the Venus. It is said that the Chicxulub asteroid impact caused mega-tsunamis on Earth, but you cannot see tsunamis on Venus, since there are no oceans, but there will be an immense seismic activity. The velocity and the temperature together will vaporize some mass of the asteroid, but this factor is negligible, thus the temperature will not have a significant impact on the intensity of impact.
The impact created winds in excess of 1,000 kilometers per hour (620 mph) near the blast's center. The impact, expansion of water after filling the crater, and related seismic activity spawned megatsunamis over 100 meters (330 ft) tall, with one simulation suggesting the immediate waves from the impact may have been up to 1.5 kilometers (~1 mi) tall. The waves scoured the sea floor, leaving ripples underneath what is now Louisiana with average wavelengths of 600 meters and average wave heights of 16 meters, the largest ripples documented. Material shifted by subsequent earthquakes and the waves reached all the way to what are now Texas and Florida, and may have disturbed sediments as far as 6000 kilometers from the impact site. The impact triggered a seismic event equivalent to a Magnitude 12 earthquake at the impact site, with shockwaves generating the equivalent of Magnitude 9 to as high as 11 on the Richter scale.
The seismic activity caused by the impact will be similar to that of Earth, for reference, will be around Magnitude 9 on Richter scale.
The composition of the asteroid mainly had carbonates, thus it will be accumulated in the Venus' atmosphere as Carbon-di-oxide along with sulfates and debris, will increase its temperature slightly by the green house effect
If it is taken that the Chicxulub Asteroid impacted the Venus at a velocity that it hit the Earth, it will not have a significant impact on Venus's Axial tilt, rotation speed unlike what the hypothetical Great impact had on Earth. Although its impact is said to have an energy of 100 million megatons of TNT, The average tilt of Venus can be changed less than 400th of a degree, and its rotation period should have a difference of just 600 milliseconds. And this "small "collision will not even have a small impact on its orbit.
Although this is still considered to be a moderate impact, the effects of these impacts will be short term on terrestrial planets like Venus and Earth.