Answer:
True statements are 2, 4, 5
Explanation:
They can be broken down by chemical means because we need to break chemical bonds between two (or more) atoms.
They are pure substance because one can't separate them by physical means.
When one separate compounds on two (or more) substances, there are two (or more) different species and they all act differently.
Answer:
B. The student conducted the reaction in an open beaker, which allowed one of the products, a gas, to escape.
Explanation:
Based on the law of conservation of mass, matter is neither created nor destroyed during the course of a chemical reaction.
By this premise, the mass of reactants and products must remain the same during the course of a reaction.
- Here we find that this is not the case.
- The mass of the product reported is less than the mass of the reactants.
- The problem is that the mass of the gas bubbles produced during the course of this reaction was not accounted for.
- This leaves a mass deficit already
Answer:- The speed of the satellite is 7.6 .
Solution:- It's a unit conversion problem that could be solved using dimensional analysis which is also known as train trail method.
The given speed of the satellite is 17000 miles per hour and we are asked to convert it to kilometers per second.
given:
1 Kilometer = 0.62 mile
1 hour = 3600 second
Let's use this given info and plug in the values to make the set up as:
= 7.616
We round the answer to two significant figures, since the given number(17000) has only two significant figures.
Hence, the speed of the satellite is 7.6 .
Answer
C. Difference in temperature
Explanation
According to thermodynamics, heat transfer occurs when heat from a high temperature reservoir moves to a low temperature reservoir. For heat to be transferred, the two objects should have different temperatures with one having more temperature than the other. Heat transfer in solids is by conduction, in fluids is by convection and by radiation.