The answer you are looking for is the second option, "<span>Matter can be divided into two groups: pure substances and mixtures."
A pure substance can describe a pure element or chemically bonded elements. A pure substance cannot be broken down into further substances. An example of these would be Fe (iron) or O2 (oxygen).
A mixture is a structure made from physically combining different non-bonded substances. An example of a mixture is blood.
Both pure substances and mixtures are types of matter.</span>
Answer:
The log will float on the water because its density is lower than the liquid, so it will stay at the top due to Archimedes' principle.
Answer:
a. positive
b. negative
c. positive
d. negative
Explanation:
In a exothermic reaction, heat is written as a product (del H is negative), whereas in an endothermic reaction heat is written on the reaction side (del H is positive).
For a, it is endothermic process. We know this because to go from solid to liquid you need to put energy into the system. When we put energy into a chemical system it is said to be an endothermic reaction.
For b, it is exothermic reaction. This is because you have to lose the extra energy to go from less ordered states (gas) to more ordered state (liquid). Gas is less ordered because its molecules are freely moving and such. Another way of thinking about this question is just putting the heat on product side and think if I was going in reverse direction I would put heat in product because I would need to add heat to liquid to turn to gas (and if heat is added to product side we know its exothermic). Two ways of thinking whichever you prefer.
The rest have similar explaination.
Answer:
"Nitrate" is a polyatomic ion forms A neutral compound when combined with group a1 monotonic ion in a 1:1
Explanation:
Nitrate is a polyatomic ion with the molecular formula NO⁻ ₃. Organic complexes that comprise the nitrate ester as a functional group are also named nitrates. Nitrates are shared apparatuses of fertilizers and explosives. Almost all nitrate salts are soluble in water. Usually nitrates that enter the body by eating or drinking leave the body without harm. These nitrites in the blood cause changes in hemoglobin, or the molecules that help move oxygen in the body. Nitrates can make it so that less oxygen is available for the body to function properly.
Answer:
here are several resons that fossil foraminifera are especially valuable for determining the relative ages of marine rock layers. They have been around since the Cambrian, over 500 million years ago. They show fairly continuous evolutionary development, so different species are found at different times.
